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mariadb/sql/sql_select.cc
cmiller@zippy.cornsilk.net c34f3219b3 Merge bk-internal.mysql.com:/home/bk/mysql-4.1 
into  zippy.cornsilk.net:/home/cmiller/work/mysql/mysql-4.1-maint
2006-11-02 17:27:42 -05:00

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/* Copyright (C) 2000-2004 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* mysql_select and join optimization */
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#include "mysql_priv.h"
#include "sql_select.h"
#include <m_ctype.h>
#include <hash.h>
#include <ft_global.h>
const char *join_type_str[]={ "UNKNOWN","system","const","eq_ref","ref",
"MAYBE_REF","ALL","range","index","fulltext",
"ref_or_null","unique_subquery","index_subquery"
};
static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array);
static bool make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
DYNAMIC_ARRAY *keyuse);
static bool update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,
JOIN_TAB *join_tab,
uint tables, COND *conds,
table_map table_map, SELECT_LEX *select_lex);
static int sort_keyuse(KEYUSE *a,KEYUSE *b);
static void set_position(JOIN *join,uint index,JOIN_TAB *table,KEYUSE *key);
static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
table_map used_tables);
static void find_best_combination(JOIN *join,table_map rest_tables);
static void find_best(JOIN *join,table_map rest_tables,uint index,
double record_count,double read_time);
static uint cache_record_length(JOIN *join,uint index);
static double prev_record_reads(JOIN *join,table_map found_ref);
static bool get_best_combination(JOIN *join);
static store_key *get_store_key(THD *thd,
KEYUSE *keyuse, table_map used_tables,
KEY_PART_INFO *key_part, char *key_buff,
uint maybe_null);
static bool make_simple_join(JOIN *join,TABLE *tmp_table);
static bool make_join_select(JOIN *join,SQL_SELECT *select,COND *item);
static void make_join_readinfo(JOIN *join,uint options);
static bool only_eq_ref_tables(JOIN *join, ORDER *order, table_map tables);
static void update_depend_map(JOIN *join);
static void update_depend_map(JOIN *join, ORDER *order);
static ORDER *remove_const(JOIN *join,ORDER *first_order,COND *cond,
bool change_list, bool *simple_order);
static int return_zero_rows(JOIN *join, select_result *res,TABLE_LIST *tables,
List<Item> &fields, bool send_row,
uint select_options, const char *info,
Item *having, Procedure *proc,
SELECT_LEX_UNIT *unit);
static COND *optimize_cond(THD *thd, COND *conds,
Item::cond_result *cond_value);
static bool const_expression_in_where(COND *conds,Item *item, Item **comp_item);
static bool open_tmp_table(TABLE *table);
static bool create_myisam_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
ulong options);
static int do_select(JOIN *join,List<Item> *fields,TABLE *tmp_table,
Procedure *proc);
static int sub_select_cache(JOIN *join,JOIN_TAB *join_tab,bool end_of_records);
static int sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records);
static int flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skip_last);
static int end_send(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_send_group(JOIN *join, JOIN_TAB *join_tab,bool end_of_records);
static int end_write(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_update(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_unique_update(JOIN *join,JOIN_TAB *join_tab,
bool end_of_records);
static int end_write_group(JOIN *join, JOIN_TAB *join_tab,
bool end_of_records);
static int test_if_group_changed(List<Item_buff> &list);
static int join_read_const_table(JOIN_TAB *tab, POSITION *pos);
static int join_read_system(JOIN_TAB *tab);
static int join_read_const(JOIN_TAB *tab);
static int join_read_key(JOIN_TAB *tab);
static int join_read_always_key(JOIN_TAB *tab);
static int join_read_last_key(JOIN_TAB *tab);
static int join_no_more_records(READ_RECORD *info);
static int join_read_next(READ_RECORD *info);
static int join_init_quick_read_record(JOIN_TAB *tab);
static int test_if_quick_select(JOIN_TAB *tab);
static int join_init_read_record(JOIN_TAB *tab);
static int join_read_first(JOIN_TAB *tab);
static int join_read_next(READ_RECORD *info);
static int join_read_next_same(READ_RECORD *info);
static int join_read_last(JOIN_TAB *tab);
static int join_read_prev_same(READ_RECORD *info);
static int join_read_prev(READ_RECORD *info);
static int join_ft_read_first(JOIN_TAB *tab);
static int join_ft_read_next(READ_RECORD *info);
static int join_read_always_key_or_null(JOIN_TAB *tab);
static int join_read_next_same_or_null(READ_RECORD *info);
static COND *make_cond_for_table(COND *cond,table_map table,
table_map used_table);
static Item* part_of_refkey(TABLE *form,Field *field);
static uint find_shortest_key(TABLE *table, const key_map *usable_keys);
static bool test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,
ha_rows select_limit, bool no_changes);
static bool list_contains_unique_index(TABLE *table,
bool (*find_func) (Field *, void *), void *data);
static bool find_field_in_item_list (Field *field, void *data);
static bool find_field_in_order_list (Field *field, void *data);
static int create_sort_index(THD *thd, JOIN *join, ORDER *order,
ha_rows filesort_limit, ha_rows select_limit);
static int remove_duplicates(JOIN *join,TABLE *entry,List<Item> &fields,
Item *having);
static int remove_dup_with_compare(THD *thd, TABLE *entry, Field **field,
ulong offset,Item *having);
static int remove_dup_with_hash_index(THD *thd,TABLE *table,
uint field_count, Field **first_field,
ulong key_length,Item *having);
static int join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count);
static ulong used_blob_length(CACHE_FIELD **ptr);
static bool store_record_in_cache(JOIN_CACHE *cache);
static void reset_cache_read(JOIN_CACHE *cache);
static void reset_cache_write(JOIN_CACHE *cache);
static void read_cached_record(JOIN_TAB *tab);
static bool cmp_buffer_with_ref(JOIN_TAB *tab);
static bool setup_new_fields(THD *thd,TABLE_LIST *tables,List<Item> &fields,
List<Item> &all_fields,ORDER *new_order);
static ORDER *create_distinct_group(THD *thd, Item **ref_pointer_array,
ORDER *order, List<Item> &fields,
bool *all_order_by_fields_used);
static bool test_if_subpart(ORDER *a,ORDER *b);
static TABLE *get_sort_by_table(ORDER *a,ORDER *b,TABLE_LIST *tables);
static void calc_group_buffer(JOIN *join,ORDER *group);
static bool make_group_fields(JOIN *main_join, JOIN *curr_join);
static bool alloc_group_fields(JOIN *join,ORDER *group);
// Create list for using with tempory table
static bool change_to_use_tmp_fields(THD *thd, Item **ref_pointer_array,
List<Item> &new_list1,
List<Item> &new_list2,
uint elements, List<Item> &items);
// Create list for using with tempory table
static bool change_refs_to_tmp_fields(THD *thd, Item **ref_pointer_array,
List<Item> &new_list1,
List<Item> &new_list2,
uint elements, List<Item> &items);
static void init_tmptable_sum_functions(Item_sum **func);
static void update_tmptable_sum_func(Item_sum **func,TABLE *tmp_table);
static void copy_sum_funcs(Item_sum **func_ptr, Item_sum **end);
static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab);
static bool init_sum_functions(Item_sum **func, Item_sum **end);
static bool update_sum_func(Item_sum **func);
static void select_describe(JOIN *join, bool need_tmp_table,bool need_order,
bool distinct, const char *message=NullS);
static Item *remove_additional_cond(Item* conds);
/*
This handles SELECT with and without UNION
*/
int handle_select(THD *thd, LEX *lex, select_result *result)
{
int res;
register SELECT_LEX *select_lex = &lex->select_lex;
DBUG_ENTER("handle_select");
if (select_lex->next_select() || select_lex->master_unit()->fake_select_lex)
res=mysql_union(thd, lex, result, &lex->unit);
else
res= mysql_select(thd, &select_lex->ref_pointer_array,
(TABLE_LIST*) select_lex->table_list.first,
select_lex->with_wild, select_lex->item_list,
select_lex->where,
select_lex->order_list.elements +
select_lex->group_list.elements,
(ORDER*) select_lex->order_list.first,
(ORDER*) select_lex->group_list.first,
select_lex->having,
(ORDER*) lex->proc_list.first,
select_lex->options | thd->options,
result, &(lex->unit), &(lex->select_lex));
/* Don't set res if it's -1 as we may want this later */
DBUG_PRINT("info",("res: %d report_error: %d", res,
thd->net.report_error));
if (thd->net.report_error || res<0)
{
result->send_error(0, NullS);
result->abort();
res= 1; // Error sent to client
}
DBUG_RETURN(res);
}
/*
Function to setup clauses without sum functions
*/
inline int setup_without_group(THD *thd, Item **ref_pointer_array,
TABLE_LIST *tables,
List<Item> &fields,
List<Item> &all_fields,
COND **conds,
ORDER *order,
ORDER *group, bool *hidden_group_fields)
{
bool save_allow_sum_func;
int res;
DBUG_ENTER("setup_without_group");
save_allow_sum_func= thd->allow_sum_func;
thd->allow_sum_func= 0;
res= (setup_conds(thd, tables, conds) ||
setup_order(thd, ref_pointer_array, tables, fields, all_fields,
order) ||
setup_group(thd, ref_pointer_array, tables, fields, all_fields,
group, hidden_group_fields));
thd->allow_sum_func= save_allow_sum_func;
DBUG_RETURN(res);
}
/*****************************************************************************
Check fields, find best join, do the select and output fields.
mysql_select assumes that all tables are already opened
*****************************************************************************/
/*
Prepare of whole select (including sub queries in future).
return -1 on error
0 on success
*/
int
JOIN::prepare(Item ***rref_pointer_array,
TABLE_LIST *tables_init,
uint wild_num, COND *conds_init, uint og_num,
ORDER *order_init, ORDER *group_init,
Item *having_init,
ORDER *proc_param_init, SELECT_LEX *select_lex_arg,
SELECT_LEX_UNIT *unit_arg)
{
DBUG_ENTER("JOIN::prepare");
// to prevent double initialization on EXPLAIN
if (optimized)
DBUG_RETURN(0);
conds= conds_init;
order= order_init;
group_list= group_init;
having= having_init;
proc_param= proc_param_init;
tables_list= tables_init;
select_lex= select_lex_arg;
select_lex->join= this;
union_part= (unit_arg->first_select()->next_select() != 0);
/* Check that all tables, fields, conds and order are ok */
if (setup_tables(tables_list) ||
setup_wild(thd, tables_list, fields_list, &all_fields, wild_num) ||
select_lex->setup_ref_array(thd, og_num) ||
setup_fields(thd, (*rref_pointer_array), tables_list, fields_list, 1,
&all_fields, 1) ||
setup_without_group(thd, (*rref_pointer_array), tables_list, fields_list,
all_fields, &conds, order, group_list,
&hidden_group_fields))
DBUG_RETURN(-1); /* purecov: inspected */
ref_pointer_array= *rref_pointer_array;
if (having)
{
thd->where="having clause";
thd->allow_sum_func=1;
select_lex->having_fix_field= 1;
bool having_fix_rc= (!having->fixed &&
(having->fix_fields(thd, tables_list, &having) ||
having->check_cols(1)));
select_lex->having_fix_field= 0;
if (having_fix_rc || thd->net.report_error)
DBUG_RETURN(-1); /* purecov: inspected */
}
// Is it subselect
{
Item_subselect *subselect;
if ((subselect= select_lex->master_unit()->item))
{
Item_subselect::trans_res res;
if ((res= subselect->select_transformer(this)) !=
Item_subselect::RES_OK)
DBUG_RETURN((res == Item_subselect::RES_ERROR));
}
}
if (having && having->with_sum_func)
having->split_sum_func2(thd, ref_pointer_array, all_fields, &having);
if (setup_ftfuncs(select_lex)) /* should be after having->fix_fields */
DBUG_RETURN(-1);
/*
Check if one one uses a not constant column with group functions
and no GROUP BY.
TODO: Add check of calculation of GROUP functions and fields:
SELECT COUNT(*)+table.col1 from table1;
*/
{
if (!group_list)
{
uint flag=0;
List_iterator_fast<Item> it(fields_list);
Item *item;
while ((item= it++))
{
if (item->with_sum_func)
flag|=1;
else if (!(flag & 2) && !item->const_during_execution())
flag|=2;
}
if (flag == 3)
{
my_error(ER_MIX_OF_GROUP_FUNC_AND_FIELDS,MYF(0));
DBUG_RETURN(-1);
}
}
TABLE_LIST *table_ptr;
for (table_ptr= tables_list ; table_ptr ; table_ptr= table_ptr->next)
tables++;
}
{
/* Caclulate the number of groups */
send_group_parts= 0;
for (ORDER *group_tmp= group_list ; group_tmp ; group_tmp= group_tmp->next)
send_group_parts++;
}
procedure= setup_procedure(thd, proc_param, result, fields_list, &error);
if (error)
goto err; /* purecov: inspected */
if (procedure)
{
if (setup_new_fields(thd, tables_list, fields_list, all_fields,
procedure->param_fields))
goto err; /* purecov: inspected */
if (procedure->group)
{
if (!test_if_subpart(procedure->group,group_list))
{ /* purecov: inspected */
my_message(0,"Can't handle procedures with differents groups yet",
MYF(0)); /* purecov: inspected */
goto err; /* purecov: inspected */
}
}
#ifdef NOT_NEEDED
else if (!group_list && procedure->flags & PROC_GROUP)
{
my_message(0,"Select must have a group with this procedure",MYF(0));
goto err;
}
#endif
if (order && (procedure->flags & PROC_NO_SORT))
{ /* purecov: inspected */
my_message(0,"Can't use order with this procedure",MYF(0)); /* purecov: inspected */
goto err; /* purecov: inspected */
}
}
/* Init join struct */
count_field_types(&tmp_table_param, all_fields, 0);
ref_pointer_array_size= all_fields.elements*sizeof(Item*);
this->group= group_list != 0;
row_limit= ((select_distinct || order || group_list) ? HA_POS_ERROR :
unit_arg->select_limit_cnt);
/* select_limit is used to decide if we are likely to scan the whole table */
select_limit= unit_arg->select_limit_cnt;
if (having || (select_options & OPTION_FOUND_ROWS))
select_limit= HA_POS_ERROR;
do_send_rows = (unit_arg->select_limit_cnt) ? 1 : 0;
unit= unit_arg;
#ifdef RESTRICTED_GROUP
if (sum_func_count && !group_list && (func_count || field_count))
{
my_message(ER_WRONG_SUM_SELECT,ER(ER_WRONG_SUM_SELECT),MYF(0));
goto err;
}
#endif
/*
We must not yet prepare the result table if it is the same as one of the
source tables (INSERT SELECT). This is checked in mysql_execute_command()
and OPTION_BUFFER_RESULT is added to the select_options. A temporary
table is then used to hold the result. The preparation may disable
indexes on the result table, which may be used during the select, if it
is the same table (Bug #6034). Do the preparation after the select phase.
*/
if (! procedure && ! test(select_options & OPTION_BUFFER_RESULT) &&
result && result->prepare(fields_list, unit_arg))
goto err; /* purecov: inspected */
if (select_lex->olap == ROLLUP_TYPE && rollup_init())
goto err;
if (alloc_func_list())
goto err;
DBUG_RETURN(0); // All OK
err:
delete procedure; /* purecov: inspected */
procedure= 0;
DBUG_RETURN(-1); /* purecov: inspected */
}
/*
test if it is known for optimisation IN subquery
SYNOPSYS
JOIN::test_in_subselect
where - pointer for variable in which conditions should be
stored if subquery is known
RETURN
1 - known
0 - unknown
*/
bool JOIN::test_in_subselect(Item **where)
{
if (conds->type() == Item::FUNC_ITEM &&
((Item_func *)this->conds)->functype() == Item_func::EQ_FUNC &&
((Item_func *)conds)->arguments()[0]->type() == Item::REF_ITEM &&
((Item_func *)conds)->arguments()[1]->type() == Item::FIELD_ITEM)
{
join_tab->info= "Using index";
*where= 0;
return 1;
}
if (conds->type() == Item::COND_ITEM &&
((class Item_func *)this->conds)->functype() ==
Item_func::COND_AND_FUNC)
{
if ((*where= remove_additional_cond(conds)))
join_tab->info= "Using index; Using where";
else
join_tab->info= "Using index";
return 1;
}
return 0;
}
/*
global select optimisation.
return 0 - success
1 - error
error code saved in field 'error'
*/
int
JOIN::optimize()
{
DBUG_ENTER("JOIN::optimize");
// to prevent double initialization on EXPLAIN
if (optimized)
DBUG_RETURN(0);
optimized= 1;
// Ignore errors of execution if option IGNORE present
if (thd->lex->ignore)
thd->lex->current_select->no_error= 1;
#ifdef HAVE_REF_TO_FIELDS // Not done yet
/* Add HAVING to WHERE if possible */
if (having && !group_list && !sum_func_count)
{
if (!conds)
{
conds= having;
having= 0;
}
else if ((conds=new Item_cond_and(conds,having)))
{
conds->fix_fields(thd, tables_list, &conds);
conds->change_ref_to_fields(thd, tables_list);
conds->top_level_item();
having= 0;
}
}
#endif
conds= optimize_cond(thd, conds, &cond_value);
if (thd->net.report_error)
{
error= 1;
DBUG_PRINT("error",("Error from optimize_cond"));
DBUG_RETURN(1);
}
{
Item::cond_result having_value;
having= optimize_cond(thd, having, &having_value);
if (thd->net.report_error)
{
error= 1;
DBUG_PRINT("error",("Error from optimize_cond"));
DBUG_RETURN(1);
}
if (cond_value == Item::COND_FALSE || having_value == Item::COND_FALSE ||
(!unit->select_limit_cnt && !(select_options & OPTION_FOUND_ROWS)))
{ /* Impossible cond */
zero_result_cause= having_value == Item::COND_FALSE ?
"Impossible HAVING" : "Impossible WHERE";
error= 0;
DBUG_RETURN(0);
}
}
/* Optimize count(*), min() and max() */
if (tables_list && tmp_table_param.sum_func_count && ! group_list)
{
int res;
/*
opt_sum_query() returns -1 if no rows match to the WHERE conditions,
or 1 if all items were resolved, or 0, or an error number HA_ERR_...
*/
if ((res=opt_sum_query(tables_list, all_fields, conds)))
{
if (res > 1)
{
thd->fatal_error();
error= res;
DBUG_RETURN(1);
}
if (res < 0)
{
zero_result_cause= "No matching min/max row";
error=0;
DBUG_RETURN(0);
}
zero_result_cause= "Select tables optimized away";
tables_list= 0; // All tables resolved
/*
Extract all table-independent conditions and replace the WHERE
clause with them. All other conditions were computed by opt_sum_query
and the MIN/MAX/COUNT function(s) have been replaced by constants,
so there is no need to compute the whole WHERE clause again.
Notice that make_cond_for_table() will always succeed to remove all
computed conditions, because opt_sum_query() is applicable only to
conjunctions.
*/
if (conds)
{
COND *table_independent_conds=
make_cond_for_table(conds, PSEUDO_TABLE_BITS, 0);
DBUG_EXECUTE("where",
print_where(table_independent_conds,
"where after opt_sum_query()"););
conds= table_independent_conds;
}
}
}
if (!tables_list)
{
error= 0;
DBUG_RETURN(0);
}
error= -1; // Error is sent to client
sort_by_table= get_sort_by_table(order, group_list, tables_list);
/* Calculate how to do the join */
thd->proc_info= "statistics";
if (make_join_statistics(this, tables_list, conds, &keyuse) ||
thd->is_fatal_error)
{
DBUG_PRINT("error",("Error: make_join_statistics() failed"));
DBUG_RETURN(1);
}
/* Remove distinct if only const tables */
select_distinct= select_distinct && (const_tables != tables);
thd->proc_info= "preparing";
if (result->initialize_tables(this))
{
DBUG_PRINT("error",("Error: initialize_tables() failed"));
DBUG_RETURN(1); // error == -1
}
if (const_table_map != found_const_table_map &&
!(select_options & SELECT_DESCRIBE) &&
(!conds ||
!(conds->used_tables() & RAND_TABLE_BIT) ||
select_lex->master_unit() == &thd->lex->unit)) // upper level SELECT
{
zero_result_cause= "no matching row in const table";
DBUG_PRINT("error",("Error: %s", zero_result_cause));
error= 0;
DBUG_RETURN(0);
}
if (!(thd->options & OPTION_BIG_SELECTS) &&
best_read > (double) thd->variables.max_join_size &&
!(select_options & SELECT_DESCRIBE))
{ /* purecov: inspected */
my_message(ER_TOO_BIG_SELECT, ER(ER_TOO_BIG_SELECT), MYF(0));
error= -1;
DBUG_RETURN(1);
}
if (const_tables && !thd->locked_tables &&
!(select_options & SELECT_NO_UNLOCK))
mysql_unlock_some_tables(thd, table, const_tables);
if (!conds && outer_join)
{
/* Handle the case where we have an OUTER JOIN without a WHERE */
conds=new Item_int((longlong) 1,1); // Always true
}
select=make_select(*table, const_table_map,
const_table_map, conds, &error);
if (error)
{ /* purecov: inspected */
error= -1; /* purecov: inspected */
DBUG_PRINT("error",("Error: make_select() failed"));
DBUG_RETURN(1);
}
if (make_join_select(this, select, conds))
{
zero_result_cause=
"Impossible WHERE noticed after reading const tables";
DBUG_RETURN(0); // error == 0
}
error= -1; /* if goto err */
/* Optimize distinct away if possible */
{
ORDER *org_order= order;
order=remove_const(this, order,conds,1, &simple_order);
/*
If we are using ORDER BY NULL or ORDER BY const_expression,
return result in any order (even if we are using a GROUP BY)
*/
if (!order && org_order)
skip_sort_order= 1;
}
/*
Check if we can optimize away GROUP BY/DISTINCT.
We can do that if there are no aggregate functions and the
fields in DISTINCT clause (if present) and/or columns in GROUP BY
(if present) contain direct references to all key parts of
an unique index (in whatever order).
Note that the unique keys for DISTINCT and GROUP BY should not
be the same (as long as they are unique).
The FROM clause must contain a single non-constant table.
*/
if (tables - const_tables == 1 && (group_list || select_distinct) &&
!tmp_table_param.sum_func_count)
{
if (group_list &&
list_contains_unique_index(join_tab[const_tables].table,
find_field_in_order_list,
(void *) group_list))
{
group_list= 0;
group= 0;
}
if (select_distinct &&
list_contains_unique_index(join_tab[const_tables].table,
find_field_in_item_list,
(void *) &fields_list))
{
select_distinct= 0;
}
}
if (group_list || tmp_table_param.sum_func_count)
{
if (! hidden_group_fields && rollup.state == ROLLUP::STATE_NONE)
select_distinct=0;
}
else if (select_distinct && tables - const_tables == 1)
{
/*
We are only using one table. In this case we change DISTINCT to a
GROUP BY query if:
- The GROUP BY can be done through indexes (no sort) and the ORDER
BY only uses selected fields.
(In this case we can later optimize away GROUP BY and ORDER BY)
- We are scanning the whole table without LIMIT
This can happen if:
- We are using CALC_FOUND_ROWS
- We are using an ORDER BY that can't be optimized away.
We don't want to use this optimization when we are using LIMIT
because in this case we can just create a temporary table that
holds LIMIT rows and stop when this table is full.
*/
JOIN_TAB *tab= &join_tab[const_tables];
bool all_order_fields_used;
if (order)
skip_sort_order= test_if_skip_sort_order(tab, order, select_limit, 1);
if ((group_list=create_distinct_group(thd, select_lex->ref_pointer_array,
order, fields_list,
&all_order_fields_used)))
{
bool skip_group= (skip_sort_order &&
test_if_skip_sort_order(tab, group_list, select_limit,
1) != 0);
if ((skip_group && all_order_fields_used) ||
select_limit == HA_POS_ERROR ||
(order && !skip_sort_order))
{
/* Change DISTINCT to GROUP BY */
select_distinct= 0;
no_order= !order;
if (all_order_fields_used)
{
if (order && skip_sort_order)
{
/*
Force MySQL to read the table in sorted order to get result in
ORDER BY order.
*/
tmp_table_param.quick_group=0;
}
order=0;
}
group=1; // For end_write_group
}
else
group_list= 0;
}
else if (thd->is_fatal_error) // End of memory
DBUG_RETURN(1);
}
simple_group= 0;
{
ORDER *old_group_list;
group_list= remove_const(this, (old_group_list= group_list), conds,
rollup.state == ROLLUP::STATE_NONE,
&simple_group);
if (old_group_list && !group_list)
select_distinct= 0;
}
if (!group_list && group)
{
order=0; // The output has only one row
simple_order=1;
select_distinct= 0; // No need in distinct for 1 row
}
calc_group_buffer(this, group_list);
send_group_parts= tmp_table_param.group_parts; /* Save org parts */
if (procedure && procedure->group)
{
group_list= procedure->group= remove_const(this, procedure->group, conds,
1, &simple_group);
calc_group_buffer(this, group_list);
}
if (test_if_subpart(group_list, order) ||
(!group_list && tmp_table_param.sum_func_count))
order=0;
// Can't use sort on head table if using row cache
if (full_join)
{
if (group_list)
simple_group=0;
if (order)
simple_order=0;
}
/*
Check if we need to create a temporary table.
This has to be done if all tables are not already read (const tables)
and one of the following conditions holds:
- We are using DISTINCT (simple distinct's are already optimized away)
- We are using an ORDER BY or GROUP BY on fields not in the first table
- We are using different ORDER BY and GROUP BY orders
- The user wants us to buffer the result.
*/
need_tmp= (const_tables != tables &&
((select_distinct || !simple_order || !simple_group) ||
(group_list && order) ||
test(select_options & OPTION_BUFFER_RESULT)));
// No cache for MATCH
make_join_readinfo(this,
(select_options & (SELECT_DESCRIBE |
SELECT_NO_JOIN_CACHE)) |
(select_lex->ftfunc_list->elements ?
SELECT_NO_JOIN_CACHE : 0));
/* Perform FULLTEXT search before all regular searches */
if (!(select_options & SELECT_DESCRIBE))
init_ftfuncs(thd, select_lex, test(order));
/*
is this simple IN subquery?
*/
if (!group_list && !order &&
unit->item && unit->item->substype() == Item_subselect::IN_SUBS &&
tables == 1 && conds &&
!unit->first_select()->next_select())
{
if (!having)
{
Item *where= 0;
if (join_tab[0].type == JT_EQ_REF &&
join_tab[0].ref.items[0]->name == in_left_expr_name)
{
if (test_in_subselect(&where))
{
join_tab[0].type= JT_UNIQUE_SUBQUERY;
error= 0;
DBUG_RETURN(unit->item->
change_engine(new
subselect_uniquesubquery_engine(thd,
join_tab,
unit->item,
where)));
}
}
else if (join_tab[0].type == JT_REF &&
join_tab[0].ref.items[0]->name == in_left_expr_name)
{
if (test_in_subselect(&where))
{
join_tab[0].type= JT_INDEX_SUBQUERY;
error= 0;
DBUG_RETURN(unit->item->
change_engine(new
subselect_indexsubquery_engine(thd,
join_tab,
unit->item,
where,
0)));
}
}
} else if (join_tab[0].type == JT_REF_OR_NULL &&
join_tab[0].ref.items[0]->name == in_left_expr_name &&
having->type() == Item::FUNC_ITEM &&
((Item_func *) having)->functype() ==
Item_func::ISNOTNULLTEST_FUNC)
{
join_tab[0].type= JT_INDEX_SUBQUERY;
error= 0;
if ((conds= remove_additional_cond(conds)))
join_tab->info= "Using index; Using where";
else
join_tab->info= "Using index";
DBUG_RETURN(unit->item->
change_engine(new subselect_indexsubquery_engine(thd,
join_tab,
unit->item,
conds,
1)));
}
}
/*
Need to tell Innobase that to play it safe, it should fetch all
columns of the tables: this is because MySQL may build row
pointers for the rows, and for all columns of the primary key the
field->query_id has not necessarily been set to thd->query_id by
MySQL.
*/
#ifdef HAVE_INNOBASE_DB
if (need_tmp || select_distinct || group_list || order)
{
for (uint i_h = const_tables; i_h < tables; i_h++)
{
TABLE* table_h = join_tab[i_h].table;
table_h->file->extra(HA_EXTRA_RETRIEVE_PRIMARY_KEY);
}
}
#endif
DBUG_EXECUTE("info",TEST_join(this););
/*
Because filesort always does a full table scan or a quick range scan
we must add the removed reference to the select for the table.
We only need to do this when we have a simple_order or simple_group
as in other cases the join is done before the sort.
*/
if (const_tables != tables &&
(order || group_list) &&
join_tab[const_tables].type != JT_ALL &&
join_tab[const_tables].type != JT_FT &&
join_tab[const_tables].type != JT_REF_OR_NULL &&
(order && simple_order || group_list && simple_group))
{
if (add_ref_to_table_cond(thd,&join_tab[const_tables]))
DBUG_RETURN(1);
}
if (!(select_options & SELECT_BIG_RESULT) &&
((group_list && const_tables != tables &&
(!simple_group ||
!test_if_skip_sort_order(&join_tab[const_tables], group_list,
unit->select_limit_cnt, 0))) ||
select_distinct) &&
tmp_table_param.quick_group && !procedure)
{
need_tmp=1; simple_order=simple_group=0; // Force tmp table without sort
}
tmp_having= having;
if (select_options & SELECT_DESCRIBE)
{
error= 0;
DBUG_RETURN(0);
}
having= 0;
/* Create a tmp table if distinct or if the sort is too complicated */
if (need_tmp)
{
DBUG_PRINT("info",("Creating tmp table"));
thd->proc_info="Creating tmp table";
init_items_ref_array();
tmp_table_param.hidden_field_count= (all_fields.elements -
fields_list.elements);
ORDER *tmp_group= ((!simple_group && !procedure &&
!(test_flags & TEST_NO_KEY_GROUP)) ? group_list :
(ORDER*) 0);
/*
Pushing LIMIT to the temporary table creation is not applicable
when there is ORDER BY or GROUP BY or there is no GROUP BY, but
there are aggregate functions, because in all these cases we need
all result rows.
*/
ha_rows tmp_rows_limit= ((order == 0 || skip_sort_order ||
test(select_options & OPTION_BUFFER_RESULT)) &&
!tmp_group &&
!thd->lex->current_select->with_sum_func) ?
select_limit : HA_POS_ERROR;
if (!(exec_tmp_table1 =
create_tmp_table(thd, &tmp_table_param, all_fields,
tmp_group,
group_list ? 0 : select_distinct,
group_list && simple_group,
select_options,
tmp_rows_limit,
(char *) "")))
DBUG_RETURN(1);
/*
We don't have to store rows in temp table that doesn't match HAVING if:
- we are sorting the table and writing complete group rows to the
temp table.
- We are using DISTINCT without resolving the distinct as a GROUP BY
on all columns.
If having is not handled here, it will be checked before the row
is sent to the client.
*/
if (tmp_having &&
(sort_and_group || (exec_tmp_table1->distinct && !group_list)))
having= tmp_having;
/* if group or order on first table, sort first */
if (group_list && simple_group)
{
DBUG_PRINT("info",("Sorting for group"));
thd->proc_info="Sorting for group";
if (create_sort_index(thd, this, group_list,
HA_POS_ERROR, HA_POS_ERROR) ||
alloc_group_fields(this, group_list) ||
make_sum_func_list(all_fields, fields_list, 1))
DBUG_RETURN(1);
group_list=0;
}
else
{
if (make_sum_func_list(all_fields, fields_list, 0))
DBUG_RETURN(1);
if (!group_list && ! exec_tmp_table1->distinct && order && simple_order)
{
DBUG_PRINT("info",("Sorting for order"));
thd->proc_info="Sorting for order";
if (create_sort_index(thd, this, order,
HA_POS_ERROR, HA_POS_ERROR))
DBUG_RETURN(1);
order=0;
}
}
/*
Optimize distinct when used on some of the tables
SELECT DISTINCT t1.a FROM t1,t2 WHERE t1.b=t2.b
In this case we can stop scanning t2 when we have found one t1.a
*/
if (exec_tmp_table1->distinct)
{
table_map used_tables= thd->used_tables;
JOIN_TAB *last_join_tab= join_tab+tables-1;
do
{
if (used_tables & last_join_tab->table->map)
break;
last_join_tab->not_used_in_distinct=1;
} while (last_join_tab-- != join_tab);
/* Optimize "select distinct b from t1 order by key_part_1 limit #" */
if (order && skip_sort_order)
{
/* Should always succeed */
if (test_if_skip_sort_order(&join_tab[const_tables],
order, unit->select_limit_cnt, 0))
order=0;
}
}
if (thd->lex->subqueries)
{
if (!(tmp_join= (JOIN*)thd->alloc(sizeof(JOIN))))
DBUG_RETURN(-1);
error= 0; // Ensure that tmp_join.error= 0
restore_tmp();
}
}
error= 0;
DBUG_RETURN(0);
}
/*
Restore values in temporary join
*/
void JOIN::restore_tmp()
{
memcpy(tmp_join, this, (size_t) sizeof(JOIN));
}
int
JOIN::reinit()
{
DBUG_ENTER("JOIN::reinit");
/* TODO move to unit reinit */
unit->offset_limit_cnt =select_lex->offset_limit;
unit->select_limit_cnt =select_lex->select_limit+select_lex->offset_limit;
if (unit->select_limit_cnt < select_lex->select_limit)
unit->select_limit_cnt= HA_POS_ERROR; // no limit
if (unit->select_limit_cnt == HA_POS_ERROR)
select_lex->options&= ~OPTION_FOUND_ROWS;
if (!optimized && setup_tables(tables_list))
DBUG_RETURN(1);
/* Reset of sum functions */
first_record= 0;
if (exec_tmp_table1)
{
exec_tmp_table1->file->extra(HA_EXTRA_RESET_STATE);
exec_tmp_table1->file->delete_all_rows();
free_io_cache(exec_tmp_table1);
filesort_free_buffers(exec_tmp_table1);
}
if (exec_tmp_table2)
{
exec_tmp_table2->file->extra(HA_EXTRA_RESET_STATE);
exec_tmp_table2->file->delete_all_rows();
free_io_cache(exec_tmp_table2);
filesort_free_buffers(exec_tmp_table2);
}
if (items0)
set_items_ref_array(items0);
if (join_tab_save)
memcpy(join_tab, join_tab_save, sizeof(JOIN_TAB) * tables);
if (tmp_join)
restore_tmp();
if (sum_funcs)
{
Item_sum *func, **func_ptr= sum_funcs;
while ((func= *(func_ptr++)))
func->clear();
}
DBUG_RETURN(0);
}
bool
JOIN::save_join_tab()
{
if (!join_tab_save && select_lex->master_unit()->uncacheable)
{
if (!(join_tab_save= (JOIN_TAB*)thd->memdup((gptr) join_tab,
sizeof(JOIN_TAB) * tables)))
return 1;
}
return 0;
}
/*
Exec select
*/
void
JOIN::exec()
{
List<Item> *columns_list= &fields_list;
int tmp_error;
DBUG_ENTER("JOIN::exec");
error= 0;
if (procedure)
{
procedure_fields_list= fields_list;
if (procedure->change_columns(procedure_fields_list) ||
result->prepare(procedure_fields_list, unit))
{
thd->limit_found_rows= thd->examined_row_count= 0;
DBUG_VOID_RETURN;
}
columns_list= &procedure_fields_list;
}
else if (test(select_options & OPTION_BUFFER_RESULT) &&
result && result->prepare(fields_list, unit))
{
error= 1;
thd->limit_found_rows= thd->examined_row_count= 0;
DBUG_VOID_RETURN;
}
if (!tables_list && (tables || !select_lex->with_sum_func))
{ // Only test of functions
if (select_options & SELECT_DESCRIBE)
select_describe(this, FALSE, FALSE, FALSE,
(zero_result_cause?zero_result_cause:"No tables used"));
else
{
result->send_fields(*columns_list, 1);
/*
We have to test for 'conds' here as the WHERE may not be constant
even if we don't have any tables for prepared statements or if
conds uses something like 'rand()'.
*/
if (cond_value != Item::COND_FALSE &&
(!conds || conds->val_int()) &&
(!having || having->val_int()))
{
if (do_send_rows &&
(procedure ? (procedure->send_row(procedure_fields_list) ||
procedure->end_of_records()) : result->send_data(fields_list)))
error= 1;
else
{
error= (int) result->send_eof();
send_records= ((select_options & OPTION_FOUND_ROWS) ? 1 :
thd->sent_row_count);
}
}
else
{
error=(int) result->send_eof();
send_records= 0;
}
}
/* Single select (without union) always returns 0 or 1 row */
thd->limit_found_rows= send_records;
thd->examined_row_count= 0;
DBUG_VOID_RETURN;
}
/*
Don't reset the found rows count if there're no tables as
FOUND_ROWS() may be called. Never reset the examined row count here.
It must be accumulated from all join iterations of all join parts.
*/
if (tables)
thd->limit_found_rows= 0;
if (zero_result_cause)
{
(void) return_zero_rows(this, result, tables_list, *columns_list,
send_row_on_empty_set(),
select_options,
zero_result_cause,
having, procedure,
unit);
DBUG_VOID_RETURN;
}
if (select_options & SELECT_DESCRIBE)
{
/*
Check if we managed to optimize ORDER BY away and don't use temporary
table to resolve ORDER BY: in that case, we only may need to do
filesort for GROUP BY.
*/
if (!order && !no_order && (!skip_sort_order || !need_tmp))
{
/*
Reset 'order' to 'group_list' and reinit variables describing
'order'
*/
order= group_list;
simple_order= simple_group;
skip_sort_order= 0;
}
if (order &&
(const_tables == tables ||
((simple_order || skip_sort_order) &&
test_if_skip_sort_order(&join_tab[const_tables], order,
select_limit, 0))))
order=0;
having= tmp_having;
select_describe(this, need_tmp,
order != 0 && !skip_sort_order,
select_distinct,
!tables ? "No tables used" : NullS);
DBUG_VOID_RETURN;
}
JOIN *curr_join= this;
List<Item> *curr_all_fields= &all_fields;
List<Item> *curr_fields_list= &fields_list;
TABLE *curr_tmp_table= 0;
/*
Initialize examined rows here because the values from all join parts
must be accumulated in examined_row_count. Hence every join
iteration must count from zero.
*/
curr_join->examined_rows= 0;
/* Create a tmp table if distinct or if the sort is too complicated */
if (need_tmp)
{
if (tmp_join)
curr_join= tmp_join;
curr_tmp_table= exec_tmp_table1;
/* Copy data to the temporary table */
thd->proc_info= "Copying to tmp table";
if ((tmp_error= do_select(curr_join, (List<Item> *) 0, curr_tmp_table, 0)))
{
error= tmp_error;
DBUG_VOID_RETURN;
}
curr_tmp_table->file->info(HA_STATUS_VARIABLE);
if (curr_join->having)
curr_join->having= curr_join->tmp_having= 0; // Allready done
/* Change sum_fields reference to calculated fields in tmp_table */
curr_join->all_fields= *curr_all_fields;
if (!items1)
{
items1= items0 + all_fields.elements;
if (sort_and_group || curr_tmp_table->group)
{
if (change_to_use_tmp_fields(thd, items1,
tmp_fields_list1, tmp_all_fields1,
fields_list.elements, all_fields))
DBUG_VOID_RETURN;
}
else
{
if (change_refs_to_tmp_fields(thd, items1,
tmp_fields_list1, tmp_all_fields1,
fields_list.elements, all_fields))
DBUG_VOID_RETURN;
}
curr_join->tmp_all_fields1= tmp_all_fields1;
curr_join->tmp_fields_list1= tmp_fields_list1;
curr_join->items1= items1;
}
curr_all_fields= &tmp_all_fields1;
curr_fields_list= &tmp_fields_list1;
curr_join->set_items_ref_array(items1);
if (sort_and_group || curr_tmp_table->group)
{
curr_join->tmp_table_param.field_count+=
curr_join->tmp_table_param.sum_func_count+
curr_join->tmp_table_param.func_count;
curr_join->tmp_table_param.sum_func_count=
curr_join->tmp_table_param.func_count= 0;
}
else
{
curr_join->tmp_table_param.field_count+=
curr_join->tmp_table_param.func_count;
curr_join->tmp_table_param.func_count= 0;
}
// procedure can't be used inside subselect => we do nothing special for it
if (procedure)
procedure->update_refs();
if (curr_tmp_table->group)
{ // Already grouped
if (!curr_join->order && !curr_join->no_order && !skip_sort_order)
curr_join->order= curr_join->group_list; /* order by group */
curr_join->group_list= 0;
}
/*
If we have different sort & group then we must sort the data by group
and copy it to another tmp table
This code is also used if we are using distinct something
we haven't been able to store in the temporary table yet
like SEC_TO_TIME(SUM(...)).
*/
if (curr_join->group_list && (!test_if_subpart(curr_join->group_list,
curr_join->order) ||
curr_join->select_distinct) ||
(curr_join->select_distinct &&
curr_join->tmp_table_param.using_indirect_summary_function))
{ /* Must copy to another table */
DBUG_PRINT("info",("Creating group table"));
/* Free first data from old join */
curr_join->join_free(0);
if (make_simple_join(curr_join, curr_tmp_table))
DBUG_VOID_RETURN;
calc_group_buffer(curr_join, group_list);
count_field_types(&curr_join->tmp_table_param,
curr_join->tmp_all_fields1,
curr_join->select_distinct && !curr_join->group_list);
curr_join->tmp_table_param.hidden_field_count=
(curr_join->tmp_all_fields1.elements-
curr_join->tmp_fields_list1.elements);
if (exec_tmp_table2)
curr_tmp_table= exec_tmp_table2;
else
{
/* group data to new table */
if (!(curr_tmp_table=
exec_tmp_table2= create_tmp_table(thd,
&curr_join->tmp_table_param,
*curr_all_fields,
(ORDER*) 0,
curr_join->select_distinct &&
!curr_join->group_list,
1, curr_join->select_options,
HA_POS_ERROR,
(char *) "")))
DBUG_VOID_RETURN;
curr_join->exec_tmp_table2= exec_tmp_table2;
}
if (curr_join->group_list)
{
thd->proc_info= "Creating sort index";
if (curr_join->join_tab == join_tab && save_join_tab())
{
DBUG_VOID_RETURN;
}
if (create_sort_index(thd, curr_join, curr_join->group_list,
HA_POS_ERROR, HA_POS_ERROR) ||
make_group_fields(this, curr_join))
{
DBUG_VOID_RETURN;
}
}
thd->proc_info="Copying to group table";
tmp_error= -1;
if (curr_join != this)
{
if (sum_funcs2)
{
curr_join->sum_funcs= sum_funcs2;
curr_join->sum_funcs_end= sum_funcs_end2;
}
else
{
curr_join->alloc_func_list();
sum_funcs2= curr_join->sum_funcs;
sum_funcs_end2= curr_join->sum_funcs_end;
}
}
if (curr_join->make_sum_func_list(*curr_all_fields, *curr_fields_list,
1))
DBUG_VOID_RETURN;
curr_join->group_list= 0;
if ((tmp_error= do_select(curr_join, (List<Item> *) 0, curr_tmp_table,
0)))
{
error= tmp_error;
DBUG_VOID_RETURN;
}
end_read_record(&curr_join->join_tab->read_record);
curr_join->const_tables= curr_join->tables; // Mark free for join_free()
curr_join->join_tab[0].table= 0; // Table is freed
// No sum funcs anymore
if (!items2)
{
items2= items1 + all_fields.elements;
if (change_to_use_tmp_fields(thd, items2,
tmp_fields_list2, tmp_all_fields2,
fields_list.elements, tmp_all_fields1))
DBUG_VOID_RETURN;
curr_join->tmp_fields_list2= tmp_fields_list2;
curr_join->tmp_all_fields2= tmp_all_fields2;
}
curr_fields_list= &curr_join->tmp_fields_list2;
curr_all_fields= &curr_join->tmp_all_fields2;
curr_join->set_items_ref_array(items2);
curr_join->tmp_table_param.field_count+=
curr_join->tmp_table_param.sum_func_count;
curr_join->tmp_table_param.sum_func_count= 0;
}
if (curr_tmp_table->distinct)
curr_join->select_distinct=0; /* Each row is unique */
curr_join->join_free(0); /* Free quick selects */
if (curr_join->select_distinct && ! curr_join->group_list)
{
thd->proc_info="Removing duplicates";
if (curr_join->tmp_having)
curr_join->tmp_having->update_used_tables();
if (remove_duplicates(curr_join, curr_tmp_table,
*curr_fields_list, curr_join->tmp_having))
DBUG_VOID_RETURN;
curr_join->tmp_having=0;
curr_join->select_distinct=0;
}
curr_tmp_table->reginfo.lock_type= TL_UNLOCK;
if (make_simple_join(curr_join, curr_tmp_table))
DBUG_VOID_RETURN;
calc_group_buffer(curr_join, curr_join->group_list);
count_field_types(&curr_join->tmp_table_param, *curr_all_fields, 0);
}
if (procedure)
count_field_types(&curr_join->tmp_table_param, *curr_all_fields, 0);
if (curr_join->group || curr_join->tmp_table_param.sum_func_count ||
(procedure && (procedure->flags & PROC_GROUP)))
{
if (make_group_fields(this, curr_join))
{
DBUG_VOID_RETURN;
}
if (!items3)
{
if (!items0)
init_items_ref_array();
items3= ref_pointer_array + (all_fields.elements*4);
setup_copy_fields(thd, &curr_join->tmp_table_param,
items3, tmp_fields_list3, tmp_all_fields3,
curr_fields_list->elements, *curr_all_fields);
tmp_table_param.save_copy_funcs= curr_join->tmp_table_param.copy_funcs;
tmp_table_param.save_copy_field= curr_join->tmp_table_param.copy_field;
tmp_table_param.save_copy_field_end=
curr_join->tmp_table_param.copy_field_end;
curr_join->tmp_all_fields3= tmp_all_fields3;
curr_join->tmp_fields_list3= tmp_fields_list3;
}
else
{
curr_join->tmp_table_param.copy_funcs= tmp_table_param.save_copy_funcs;
curr_join->tmp_table_param.copy_field= tmp_table_param.save_copy_field;
curr_join->tmp_table_param.copy_field_end=
tmp_table_param.save_copy_field_end;
}
curr_fields_list= &tmp_fields_list3;
curr_all_fields= &tmp_all_fields3;
curr_join->set_items_ref_array(items3);
if (curr_join->make_sum_func_list(*curr_all_fields, *curr_fields_list,
1) || thd->is_fatal_error)
DBUG_VOID_RETURN;
}
if (curr_join->group_list || curr_join->order)
{
DBUG_PRINT("info",("Sorting for send_fields"));
thd->proc_info="Sorting result";
/* If we have already done the group, add HAVING to sorted table */
if (curr_join->tmp_having && ! curr_join->group_list &&
! curr_join->sort_and_group)
{
// Some tables may have been const
curr_join->tmp_having->update_used_tables();
JOIN_TAB *curr_table= &curr_join->join_tab[curr_join->const_tables];
table_map used_tables= (curr_join->const_table_map |
curr_table->table->map);
Item* sort_table_cond= make_cond_for_table(curr_join->tmp_having,
used_tables,
used_tables);
if (sort_table_cond)
{
if (!curr_table->select)
if (!(curr_table->select= new SQL_SELECT))
DBUG_VOID_RETURN;
if (!curr_table->select->cond)
curr_table->select->cond= sort_table_cond;
else // This should never happen
{
if (!(curr_table->select->cond=
new Item_cond_and(curr_table->select->cond,
sort_table_cond)))
DBUG_VOID_RETURN;
/*
Item_cond_and do not need fix_fields for execution, its parameters
are fixed or do not need fix_fields, too
*/
curr_table->select->cond->quick_fix_field();
}
curr_table->select_cond= curr_table->select->cond;
curr_table->select_cond->top_level_item();
DBUG_EXECUTE("where",print_where(curr_table->select->cond,
"select and having"););
curr_join->tmp_having= make_cond_for_table(curr_join->tmp_having,
~ (table_map) 0,
~used_tables);
DBUG_EXECUTE("where",print_where(curr_join->tmp_having,
"having after sort"););
}
}
{
if (group)
curr_join->select_limit= HA_POS_ERROR;
else
{
/*
We can abort sorting after thd->select_limit rows if we there is no
WHERE clause for any tables after the sorted one.
*/
JOIN_TAB *curr_table= &curr_join->join_tab[curr_join->const_tables+1];
JOIN_TAB *end_table= &curr_join->join_tab[curr_join->tables];
for (; curr_table < end_table ; curr_table++)
{
/*
table->keyuse is set in the case there was an original WHERE clause
on the table that was optimized away.
table->on_expr tells us that it was a LEFT JOIN and there will be
at least one row generated from the table.
*/
if (curr_table->select_cond ||
(curr_table->keyuse && !curr_table->on_expr))
{
/* We have to sort all rows */
curr_join->select_limit= HA_POS_ERROR;
break;
}
}
}
if (curr_join->join_tab == join_tab && save_join_tab())
{
DBUG_VOID_RETURN;
}
/*
Here we sort rows for ORDER BY/GROUP BY clause, if the optimiser
chose FILESORT to be faster than INDEX SCAN or there is no
suitable index present.
Note, that create_sort_index calls test_if_skip_sort_order and may
finally replace sorting with index scan if there is a LIMIT clause in
the query. XXX: it's never shown in EXPLAIN!
OPTION_FOUND_ROWS supersedes LIMIT and is taken into account.
*/
if (create_sort_index(thd, curr_join,
curr_join->group_list ?
curr_join->group_list : curr_join->order,
curr_join->select_limit,
(select_options & OPTION_FOUND_ROWS ?
HA_POS_ERROR : unit->select_limit_cnt)))
DBUG_VOID_RETURN;
}
}
curr_join->having= curr_join->tmp_having;
thd->proc_info="Sending data";
error= thd->net.report_error ? -1 :
do_select(curr_join, curr_fields_list, NULL, procedure);
thd->limit_found_rows= curr_join->send_records;
/* Accumulate the counts from all join iterations of all join parts. */
thd->examined_row_count+= curr_join->examined_rows;
DBUG_PRINT("counts", ("thd->examined_row_count: %lu",
(ulong) thd->examined_row_count));
DBUG_VOID_RETURN;
}
/*
Clean up join. Return error that hold JOIN.
*/
int
JOIN::cleanup()
{
DBUG_ENTER("JOIN::cleanup");
select_lex->join= 0;
if (tmp_join)
{
if (join_tab != tmp_join->join_tab)
{
JOIN_TAB *tab, *end;
for (tab= join_tab, end= tab+tables ; tab != end ; tab++)
{
tab->cleanup();
}
}
tmp_join->tmp_join= 0;
tmp_table_param.copy_field=0;
DBUG_RETURN(tmp_join->cleanup());
}
lock=0; // It's faster to unlock later
join_free(1);
if (exec_tmp_table1)
free_tmp_table(thd, exec_tmp_table1);
if (exec_tmp_table2)
free_tmp_table(thd, exec_tmp_table2);
delete select;
delete_dynamic(&keyuse);
delete procedure;
for (SELECT_LEX_UNIT *lex_unit= select_lex->first_inner_unit();
lex_unit != 0;
lex_unit= lex_unit->next_unit())
{
error|= lex_unit->cleanup();
}
DBUG_RETURN(error);
}
int
mysql_select(THD *thd, Item ***rref_pointer_array,
TABLE_LIST *tables, uint wild_num, List<Item> &fields,
COND *conds, uint og_num, ORDER *order, ORDER *group,
Item *having, ORDER *proc_param, ulong select_options,
select_result *result, SELECT_LEX_UNIT *unit,
SELECT_LEX *select_lex)
{
int err;
bool free_join= 1;
DBUG_ENTER("mysql_select");
JOIN *join;
if (select_lex->join != 0)
{
join= select_lex->join;
// is it single SELECT in derived table, called in derived table creation
if (select_lex->linkage != DERIVED_TABLE_TYPE ||
(select_options & SELECT_DESCRIBE))
{
if (select_lex->linkage != GLOBAL_OPTIONS_TYPE)
{
//here is EXPLAIN of subselect or derived table
if (join->change_result(result))
{
DBUG_RETURN(-1);
}
}
else
{
if (join->prepare(rref_pointer_array, tables, wild_num,
conds, og_num, order, group, having, proc_param,
select_lex, unit))
{
goto err;
}
}
}
free_join= 0;
join->select_options= select_options;
}
else
{
if (!(join= new JOIN(thd, fields, select_options, result)))
DBUG_RETURN(-1);
thd->proc_info="init";
thd->used_tables=0; // Updated by setup_fields
if (join->prepare(rref_pointer_array, tables, wild_num,
conds, og_num, order, group, having, proc_param,
select_lex, unit))
{
goto err;
}
}
if ((err= join->optimize()))
{
goto err; // 1
}
if (thd->lex->describe & DESCRIBE_EXTENDED)
{
join->conds_history= join->conds;
join->having_history= (join->having?join->having:join->tmp_having);
}
if (thd->net.report_error)
goto err;
join->exec();
if (thd->lex->describe & DESCRIBE_EXTENDED)
{
select_lex->where= join->conds_history;
select_lex->having= join->having_history;
}
err:
if (free_join)
{
thd->proc_info="end";
err= join->cleanup();
if (thd->net.report_error)
err= -1;
delete join;
DBUG_RETURN(err);
}
DBUG_RETURN(join->error);
}
/*****************************************************************************
Create JOIN_TABS, make a guess about the table types,
Approximate how many records will be used in each table
*****************************************************************************/
static ha_rows get_quick_record_count(THD *thd, SQL_SELECT *select,
TABLE *table,
const key_map *keys,ha_rows limit)
{
int error;
DBUG_ENTER("get_quick_record_count");
if (select)
{
select->head=table;
table->reginfo.impossible_range=0;
if ((error= select->test_quick_select(thd, *(key_map *)keys,(table_map) 0,
limit, 0)) == 1)
DBUG_RETURN(select->quick->records);
if (error == -1)
{
table->reginfo.impossible_range=1;
DBUG_RETURN(0);
}
DBUG_PRINT("warning",("Couldn't use record count on const keypart"));
}
DBUG_RETURN(HA_POS_ERROR); /* This shouldn't happend */
}
/*
Calculate the best possible join and initialize the join structure
RETURN VALUES
0 ok
1 Fatal error
*/
static bool
make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
DYNAMIC_ARRAY *keyuse_array)
{
int error;
uint i,table_count,const_count,key;
table_map found_const_table_map, all_table_map, found_ref, refs;
key_map const_ref, eq_part;
TABLE **table_vector;
JOIN_TAB *stat,*stat_end,*s,**stat_ref;
KEYUSE *keyuse,*start_keyuse;
table_map outer_join=0;
JOIN_TAB *stat_vector[MAX_TABLES+1];
DBUG_ENTER("make_join_statistics");
table_count=join->tables;
stat=(JOIN_TAB*) join->thd->calloc(sizeof(JOIN_TAB)*table_count);
stat_ref=(JOIN_TAB**) join->thd->alloc(sizeof(JOIN_TAB*)*MAX_TABLES);
table_vector=(TABLE**) join->thd->alloc(sizeof(TABLE*)*(table_count*2));
if (!stat || !stat_ref || !table_vector)
DBUG_RETURN(1); // Eom /* purecov: inspected */
join->best_ref=stat_vector;
stat_end=stat+table_count;
found_const_table_map= all_table_map=0;
const_count=0;
for (s=stat,i=0 ; tables ; s++,tables=tables->next,i++)
{
TABLE *table;
stat_vector[i]=s;
s->keys.init();
s->const_keys.init();
s->checked_keys.init();
s->needed_reg.init();
table_vector[i]=s->table=table=tables->table;
error= table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
if(error)
{
table->file->print_error(error, MYF(0));
DBUG_RETURN(1);
}
table->quick_keys.clear_all();
table->reginfo.join_tab=s;
table->reginfo.not_exists_optimize=0;
bzero((char*) table->const_key_parts, sizeof(key_part_map)*table->keys);
all_table_map|= table->map;
s->join=join;
s->info=0; // For describe
if ((s->on_expr=tables->on_expr))
{
/* Left join */
if (!table->file->records)
{ // Empty table
s->key_dependent=s->dependent=0; // Ignore LEFT JOIN depend.
set_position(join,const_count++,s,(KEYUSE*) 0);
continue;
}
s->key_dependent=s->dependent=
s->on_expr->used_tables() & ~(table->map);
if (table->outer_join & JOIN_TYPE_LEFT)
s->dependent|=stat_vector[i-1]->dependent | table_vector[i-1]->map;
if (tables->outer_join & JOIN_TYPE_RIGHT)
s->dependent|=tables->next->table->map;
outer_join|=table->map;
continue;
}
if (tables->straight) // We don't have to move this
s->dependent= table_vector[i-1]->map | stat_vector[i-1]->dependent;
else
s->dependent=(table_map) 0;
s->key_dependent=(table_map) 0;
if ((table->system || table->file->records <= 1) && ! s->dependent &&
!(table->file->table_flags() & HA_NOT_EXACT_COUNT) &&
!table->fulltext_searched)
{
set_position(join,const_count++,s,(KEYUSE*) 0);
}
}
stat_vector[i]=0;
join->outer_join=outer_join;
/*
If outer join: Re-arrange tables in stat_vector so that outer join
tables are after all tables it is dependent of.
For example: SELECT * from A LEFT JOIN B ON B.c=C.c, C WHERE A.C=C.C
Will shift table B after table C.
*/
if (outer_join)
{
table_map used_tables=0L;
for (i=0 ; i < join->tables-1 ; i++)
{
if (stat_vector[i]->dependent & ~used_tables)
{
JOIN_TAB *save= stat_vector[i];
uint j;
for (j=i+1;
j < join->tables && stat_vector[j]->dependent & ~used_tables;
j++)
{
JOIN_TAB *tmp=stat_vector[j]; // Move element up
stat_vector[j]=save;
save=tmp;
}
if (j == join->tables)
{
join->tables=0; // Don't use join->table
my_error(ER_WRONG_OUTER_JOIN,MYF(0));
DBUG_RETURN(1);
}
stat_vector[i]=stat_vector[j];
stat_vector[j]=save;
}
used_tables|= stat_vector[i]->table->map;
}
}
if (conds || outer_join)
if (update_ref_and_keys(join->thd, keyuse_array, stat, join->tables,
conds, ~outer_join, join->select_lex))
DBUG_RETURN(1);
/* Read tables with 0 or 1 rows (system tables) */
join->const_table_map= 0;
for (POSITION *p_pos=join->positions, *p_end=p_pos+const_count;
p_pos < p_end ;
p_pos++)
{
int tmp;
s= p_pos->table;
s->type=JT_SYSTEM;
join->const_table_map|=s->table->map;
if ((tmp=join_read_const_table(s, p_pos)))
{
if (tmp > 0)
DBUG_RETURN(1); // Fatal error
}
else
found_const_table_map|= s->table->map;
}
/* loop until no more const tables are found */
int ref_changed;
do
{
ref_changed = 0;
found_ref=0;
/*
We only have to loop from stat_vector + const_count as
set_position() will move all const_tables first in stat_vector
*/
for (JOIN_TAB **pos=stat_vector+const_count ; (s= *pos) ; pos++)
{
TABLE *table=s->table;
if (s->dependent) // If dependent on some table
{
// All dep. must be constants
if (s->dependent & ~(found_const_table_map))
continue;
if (table->file->records <= 1L &&
!(table->file->table_flags() & HA_NOT_EXACT_COUNT))
{ // system table
int tmp= 0;
s->type=JT_SYSTEM;
join->const_table_map|=table->map;
set_position(join,const_count++,s,(KEYUSE*) 0);
if ((tmp= join_read_const_table(s,join->positions+const_count-1)))
{
if (tmp > 0)
DBUG_RETURN(1); // Fatal error
}
else
found_const_table_map|= table->map;
continue;
}
}
/* check if table can be read by key or table only uses const refs */
if ((keyuse=s->keyuse))
{
s->type= JT_REF;
while (keyuse->table == table)
{
start_keyuse=keyuse;
key=keyuse->key;
s->keys.set_bit(key); // QQ: remove this ?
refs=0;
const_ref.clear_all();
eq_part.clear_all();
do
{
if (keyuse->val->type() != Item::NULL_ITEM && !keyuse->optimize)
{
if (!((~found_const_table_map) & keyuse->used_tables))
const_ref.set_bit(keyuse->keypart);
else
refs|=keyuse->used_tables;
eq_part.set_bit(keyuse->keypart);
}
keyuse++;
} while (keyuse->table == table && keyuse->key == key);
if (eq_part.is_prefix(table->key_info[key].key_parts) &&
((table->key_info[key].flags & (HA_NOSAME | HA_END_SPACE_KEY)) ==
HA_NOSAME) &&
!table->fulltext_searched)
{
if (const_ref == eq_part)
{ // Found everything for ref.
int tmp;
ref_changed = 1;
s->type= JT_CONST;
join->const_table_map|=table->map;
set_position(join,const_count++,s,start_keyuse);
if (create_ref_for_key(join, s, start_keyuse,
found_const_table_map))
DBUG_RETURN(1);
if ((tmp=join_read_const_table(s,
join->positions+const_count-1)))
{
if (tmp > 0)
DBUG_RETURN(1); // Fatal error
}
else
found_const_table_map|= table->map;
break;
}
else
found_ref|= refs; // Table is const if all refs are const
}
}
}
}
} while (join->const_table_map & found_ref && ref_changed);
/* Calc how many (possible) matched records in each table */
for (s=stat ; s < stat_end ; s++)
{
if (s->type == JT_SYSTEM || s->type == JT_CONST)
{
/* Only one matching row */
s->found_records=s->records=s->read_time=1; s->worst_seeks=1.0;
continue;
}
/* Approximate found rows and time to read them */
s->found_records=s->records=s->table->file->records;
s->read_time=(ha_rows) s->table->file->scan_time();
/*
Set a max range of how many seeks we can expect when using keys
This is can't be to high as otherwise we are likely to use
table scan.
*/
s->worst_seeks= min((double) s->found_records / 10,
(double) s->read_time*3);
if (s->worst_seeks < 2.0) // Fix for small tables
s->worst_seeks=2.0;
if (! s->const_keys.is_clear_all())
{
ha_rows records;
SQL_SELECT *select;
select= make_select(s->table, found_const_table_map,
found_const_table_map,
s->on_expr ? s->on_expr : conds,
&error);
records= get_quick_record_count(join->thd, select, s->table,
&s->const_keys, join->row_limit);
s->quick=select->quick;
s->needed_reg=select->needed_reg;
select->quick=0;
if (records == 0 && s->table->reginfo.impossible_range)
{
/*
Impossible WHERE or ON expression
In case of ON, we mark that the we match one empty NULL row.
In case of WHERE, don't set found_const_table_map to get the
caller to abort with a zero row result.
*/
join->const_table_map|= s->table->map;
set_position(join,const_count++,s,(KEYUSE*) 0);
s->type= JT_CONST;
if (s->on_expr)
{
/* Generate empty row */
s->info= "Impossible ON condition";
found_const_table_map|= s->table->map;
s->type= JT_CONST;
mark_as_null_row(s->table); // All fields are NULL
}
}
if (records != HA_POS_ERROR)
{
s->found_records=records;
s->read_time= (ha_rows) (s->quick ? s->quick->read_time : 0.0);
}
delete select;
}
}
/* Find best combination and return it */
join->join_tab=stat;
join->map2table=stat_ref;
join->table= join->all_tables=table_vector;
join->const_tables=const_count;
join->found_const_table_map=found_const_table_map;
if (join->const_tables != join->tables)
{
optimize_keyuse(join, keyuse_array);
find_best_combination(join,all_table_map & ~join->const_table_map);
}
else
{
memcpy((gptr) join->best_positions,(gptr) join->positions,
sizeof(POSITION)*join->const_tables);
join->best_read=1.0;
}
DBUG_RETURN(join->thd->killed || get_best_combination(join));
}
/*****************************************************************************
Check with keys are used and with tables references with tables
Updates in stat:
keys Bitmap of all used keys
const_keys Bitmap of all keys with may be used with quick_select
keyuse Pointer to possible keys
*****************************************************************************/
typedef struct key_field_t { // Used when finding key fields
Field *field;
Item *val; // May be empty if diff constant
uint level;
uint optimize;
bool eq_func;
/*
If true, the condition this struct represents will not be satisfied
when val IS NULL.
*/
bool null_rejecting;
} KEY_FIELD;
/* Values in optimize */
#define KEY_OPTIMIZE_EXISTS 1
#define KEY_OPTIMIZE_REF_OR_NULL 2
/*
Merge new key definitions to old ones, remove those not used in both
This is called for OR between different levels
To be able to do 'ref_or_null' we merge a comparison of a column
and 'column IS NULL' to one test. This is useful for sub select queries
that are internally transformed to something like:
SELECT * FROM t1 WHERE t1.key=outer_ref_field or t1.key IS NULL
KEY_FIELD::null_rejecting is processed as follows:
result has null_rejecting=true if it is set for both ORed references.
for example:
(t2.key = t1.field OR t2.key = t1.field) -> null_rejecting=true
(t2.key = t1.field OR t2.key <=> t1.field) -> null_rejecting=false
*/
static KEY_FIELD *
merge_key_fields(KEY_FIELD *start,KEY_FIELD *new_fields,KEY_FIELD *end,
uint and_level)
{
if (start == new_fields)
return start; // Impossible or
if (new_fields == end)
return start; // No new fields, skip all
KEY_FIELD *first_free=new_fields;
/* Mark all found fields in old array */
for (; new_fields != end ; new_fields++)
{
for (KEY_FIELD *old=start ; old != first_free ; old++)
{
if (old->field == new_fields->field)
{
if (new_fields->val->used_tables())
{
/*
If the value matches, we can use the key reference.
If not, we keep it until we have examined all new values
*/
if (old->val->eq(new_fields->val, old->field->binary()))
{
old->level= and_level;
old->optimize= ((old->optimize & new_fields->optimize &
KEY_OPTIMIZE_EXISTS) |
((old->optimize | new_fields->optimize) &
KEY_OPTIMIZE_REF_OR_NULL));
old->null_rejecting= (old->null_rejecting &&
new_fields->null_rejecting);
}
}
else if (old->eq_func && new_fields->eq_func &&
old->val->eq(new_fields->val, old->field->binary()))
{
old->level= and_level;
old->optimize= ((old->optimize & new_fields->optimize &
KEY_OPTIMIZE_EXISTS) |
((old->optimize | new_fields->optimize) &
KEY_OPTIMIZE_REF_OR_NULL));
old->null_rejecting= (old->null_rejecting &&
new_fields->null_rejecting);
}
else if (old->eq_func && new_fields->eq_func &&
((!old->val->used_tables() && old->val->is_null()) ||
new_fields->val->is_null()))
{
/* field = expression OR field IS NULL */
old->level= and_level;
old->optimize= KEY_OPTIMIZE_REF_OR_NULL;
/*
Remember the NOT NULL value unless the value does not depend
on other tables.
*/
if (!old->val->used_tables() && old->val->is_null())
old->val= new_fields->val;
/* The referred expression can be NULL: */
old->null_rejecting= 0;
}
else
{
/*
We are comparing two different const. In this case we can't
use a key-lookup on this so it's better to remove the value
and let the range optimzier handle it
*/
if (old == --first_free) // If last item
break;
*old= *first_free; // Remove old value
old--; // Retry this value
}
}
}
}
/* Remove all not used items */
for (KEY_FIELD *old=start ; old != first_free ;)
{
if (old->level != and_level)
{ // Not used in all levels
if (old == --first_free)
break;
*old= *first_free; // Remove old value
continue;
}
old++;
}
return first_free;
}
/*
Add a possible key to array of possible keys if it's usable as a key
SYNPOSIS
add_key_field()
key_fields Pointer to add key, if usable
and_level And level, to be stored in KEY_FIELD
field Field used in comparision
eq_func True if we used =, <=> or IS NULL
value Value used for comparison with field
usable_tables Tables which can be used for key optimization
NOTES
If we are doing a NOT NULL comparison on a NOT NULL field in a outer join
table, we store this to be able to do not exists optimization later.
RETURN
*key_fields is incremented if we stored a key in the array
*/
static void
add_key_field(KEY_FIELD **key_fields,uint and_level, Item_func *cond,
Field *field,bool eq_func,Item **value, uint num_values,
table_map usable_tables)
{
uint exists_optimize= 0;
if (!(field->flags & PART_KEY_FLAG))
{
// Don't remove column IS NULL on a LEFT JOIN table
if (!eq_func || (*value)->type() != Item::NULL_ITEM ||
!field->table->maybe_null || field->null_ptr)
return; // Not a key. Skip it
exists_optimize= KEY_OPTIMIZE_EXISTS;
}
else
{
table_map used_tables=0;
bool optimizable=0;
for (uint i=0; i<num_values; i++)
{
used_tables|=(value[i])->used_tables();
if (!((value[i])->used_tables() & (field->table->map | RAND_TABLE_BIT)))
optimizable=1;
}
if (!optimizable)
return;
if (!(usable_tables & field->table->map))
{
if (!eq_func || (*value)->type() != Item::NULL_ITEM ||
!field->table->maybe_null || field->null_ptr)
return; // Can't use left join optimize
exists_optimize= KEY_OPTIMIZE_EXISTS;
}
else
{
JOIN_TAB *stat=field->table->reginfo.join_tab;
key_map possible_keys=field->key_start;
possible_keys.intersect(field->table->keys_in_use_for_query);
stat[0].keys.merge(possible_keys); // Add possible keys
/*
Save the following cases:
Field op constant
Field LIKE constant where constant doesn't start with a wildcard
Field = field2 where field2 is in a different table
Field op formula
Field IS NULL
Field IS NOT NULL
Field BETWEEN ...
Field IN ...
*/
stat[0].key_dependent|=used_tables;
bool is_const=1;
for (uint i=0; i<num_values; i++)
is_const&= value[i]->const_item();
if (is_const)
stat[0].const_keys.merge(possible_keys);
/*
We can't always use indexes when comparing a string index to a
number. cmp_type() is checked to allow compare of dates to numbers.
eq_func is NEVER true when num_values > 1
*/
if (!eq_func)
return;
if (field->result_type() == STRING_RESULT)
{
if ((*value)->result_type() != STRING_RESULT)
{
if (field->cmp_type() != (*value)->result_type())
return;
}
else
{
/*
We can't use indexes if the effective collation
of the operation differ from the field collation.
We can also not used index on a text column, as the column may
contain 'x' 'x\t' 'x ' and 'read_next_same' will stop after
'x' when searching for WHERE col='x '
*/
if (field->cmp_type() == STRING_RESULT &&
(((Field_str*)field)->charset() != cond->compare_collation() ||
((*value)->type() != Item::NULL_ITEM &&
(field->flags & BLOB_FLAG) && !field->binary())))
return;
}
}
}
}
DBUG_ASSERT(num_values == 1);
/*
For the moment eq_func is always true. This slot is reserved for future
extensions where we want to remembers other things than just eq comparisons
*/
DBUG_ASSERT(eq_func);
/* Store possible eq field */
(*key_fields)->field= field;
(*key_fields)->eq_func= eq_func;
(*key_fields)->val= *value;
(*key_fields)->level= and_level;
(*key_fields)->optimize= exists_optimize;
/*
If the condition has form "tbl.keypart = othertbl.field" and
othertbl.field can be NULL, there will be no matches if othertbl.field
has NULL value.
We use null_rejecting in add_not_null_conds() to add
'othertbl.field IS NOT NULL' to tab->select_cond.
*/
(*key_fields)->null_rejecting= ((cond->functype() == Item_func::EQ_FUNC) &&
((*value)->type() == Item::FIELD_ITEM) &&
((Item_field*)*value)->field->maybe_null());
(*key_fields)++;
}
/*
SYNOPSIS
add_key_fields()
key_fields Add KEY_FIELD entries to this array (and move the
pointer)
and_level AND-level (a value that is different for every n-way
AND operation)
cond Condition to analyze
usable_tables Value to pass to add_key_field
*/
static void
add_key_fields(KEY_FIELD **key_fields,uint *and_level,
COND *cond, table_map usable_tables)
{
if (cond->type() == Item_func::COND_ITEM)
{
List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
KEY_FIELD *org_key_fields= *key_fields;
if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
{
Item *item;
while ((item=li++))
add_key_fields(key_fields,and_level,item,usable_tables);
for (; org_key_fields != *key_fields ; org_key_fields++)
org_key_fields->level= *and_level;
}
else
{
(*and_level)++;
add_key_fields(key_fields,and_level,li++,usable_tables);
Item *item;
while ((item=li++))
{
KEY_FIELD *start_key_fields= *key_fields;
(*and_level)++;
add_key_fields(key_fields,and_level,item,usable_tables);
*key_fields=merge_key_fields(org_key_fields,start_key_fields,
*key_fields,++(*and_level));
}
}
return;
}
/* If item is of type 'field op field/constant' add it to key_fields */
if (cond->type() != Item::FUNC_ITEM)
return;
Item_func *cond_func= (Item_func*) cond;
switch (cond_func->select_optimize()) {
case Item_func::OPTIMIZE_NONE:
break;
case Item_func::OPTIMIZE_KEY:
// BETWEEN, IN, NOT
if (cond_func->key_item()->real_item()->type() == Item::FIELD_ITEM &&
!(cond_func->used_tables() & OUTER_REF_TABLE_BIT))
add_key_field(key_fields,*and_level,cond_func,
((Item_field*)(cond_func->key_item()->real_item()))->field,
cond_func->argument_count() == 2 &&
cond_func->functype() == Item_func::IN_FUNC &&
!((Item_func_in*)cond_func)->negated,
cond_func->arguments()+1, cond_func->argument_count()-1,
usable_tables);
break;
case Item_func::OPTIMIZE_OP:
{
bool equal_func=(cond_func->functype() == Item_func::EQ_FUNC ||
cond_func->functype() == Item_func::EQUAL_FUNC);
if (cond_func->arguments()[0]->real_item()->type() == Item::FIELD_ITEM &&
!(cond_func->arguments()[0]->used_tables() & OUTER_REF_TABLE_BIT))
{
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[0])->real_item())
->field,
equal_func,
cond_func->arguments()+1, 1, usable_tables);
}
if (cond_func->arguments()[1]->real_item()->type() == Item::FIELD_ITEM &&
cond_func->functype() != Item_func::LIKE_FUNC &&
!(cond_func->arguments()[1]->used_tables() & OUTER_REF_TABLE_BIT))
{
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[1])->real_item())
->field,
equal_func,
cond_func->arguments(),1,usable_tables);
}
break;
}
case Item_func::OPTIMIZE_NULL:
/* column_name IS [NOT] NULL */
if (cond_func->arguments()[0]->real_item()->type() == Item::FIELD_ITEM &&
!(cond_func->used_tables() & OUTER_REF_TABLE_BIT))
{
Item *tmp=new Item_null;
if (unlikely(!tmp)) // Should never be true
return;
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[0])->real_item())
->field,
cond_func->functype() == Item_func::ISNULL_FUNC,
&tmp, 1, usable_tables);
}
break;
}
return;
}
/*
Add all keys with uses 'field' for some keypart
If field->and_level != and_level then only mark key_part as const_part
*/
static uint
max_part_bit(key_part_map bits)
{
uint found;
for (found=0; bits & 1 ; found++,bits>>=1) ;
return found;
}
static void
add_key_part(DYNAMIC_ARRAY *keyuse_array,KEY_FIELD *key_field)
{
Field *field=key_field->field;
TABLE *form= field->table;
KEYUSE keyuse;
if (key_field->eq_func && !(key_field->optimize & KEY_OPTIMIZE_EXISTS))
{
for (uint key=0 ; key < form->keys ; key++)
{
if (!(form->keys_in_use_for_query.is_set(key)))
continue;
if (form->key_info[key].flags & HA_FULLTEXT)
continue; // ToDo: ft-keys in non-ft queries. SerG
uint key_parts= (uint) form->key_info[key].key_parts;
for (uint part=0 ; part < key_parts ; part++)
{
if (field->eq(form->key_info[key].key_part[part].field))
{
keyuse.table= field->table;
keyuse.val = key_field->val;
keyuse.key = key;
keyuse.keypart=part;
keyuse.keypart_map= (key_part_map) 1 << part;
keyuse.used_tables=key_field->val->used_tables();
keyuse.optimize= key_field->optimize & KEY_OPTIMIZE_REF_OR_NULL;
keyuse.null_rejecting= key_field->null_rejecting;
VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
}
}
}
}
}
#define FT_KEYPART (MAX_REF_PARTS+10)
static void
add_ft_keys(DYNAMIC_ARRAY *keyuse_array,
JOIN_TAB *stat,COND *cond,table_map usable_tables)
{
Item_func_match *cond_func=NULL;
if (!cond)
return;
if (cond->type() == Item::FUNC_ITEM)
{
Item_func *func=(Item_func *)cond;
Item_func::Functype functype= func->functype();
if (functype == Item_func::FT_FUNC)
cond_func=(Item_func_match *)cond;
else if (func->arg_count == 2)
{
Item_func *arg0=(Item_func *)(func->arguments()[0]),
*arg1=(Item_func *)(func->arguments()[1]);
if (arg1->const_item() &&
((functype == Item_func::GE_FUNC && arg1->val()> 0) ||
(functype == Item_func::GT_FUNC && arg1->val()>=0)) &&
arg0->type() == Item::FUNC_ITEM &&
arg0->functype() == Item_func::FT_FUNC)
cond_func=(Item_func_match *) arg0;
else if (arg0->const_item() &&
((functype == Item_func::LE_FUNC && arg0->val()> 0) ||
(functype == Item_func::LT_FUNC && arg0->val()>=0)) &&
arg1->type() == Item::FUNC_ITEM &&
arg1->functype() == Item_func::FT_FUNC)
cond_func=(Item_func_match *) arg1;
}
}
else if (cond->type() == Item::COND_ITEM)
{
List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
{
Item *item;
while ((item=li++))
add_ft_keys(keyuse_array,stat,item,usable_tables);
}
}
if (!cond_func || cond_func->key == NO_SUCH_KEY ||
!(usable_tables & cond_func->table->map))
return;
KEYUSE keyuse;
keyuse.table= cond_func->table;
keyuse.val = cond_func;
keyuse.key = cond_func->key;
keyuse.keypart= FT_KEYPART;
keyuse.used_tables=cond_func->key_item()->used_tables();
keyuse.optimize= 0;
keyuse.keypart_map= 0;
VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
}
static int
sort_keyuse(KEYUSE *a,KEYUSE *b)
{
int res;
if (a->table->tablenr != b->table->tablenr)
return (int) (a->table->tablenr - b->table->tablenr);
if (a->key != b->key)
return (int) (a->key - b->key);
if (a->keypart != b->keypart)
return (int) (a->keypart - b->keypart);
// Place const values before other ones
if ((res= test((a->used_tables & ~OUTER_REF_TABLE_BIT)) -
test((b->used_tables & ~OUTER_REF_TABLE_BIT))))
return res;
/* Place rows that are not 'OPTIMIZE_REF_OR_NULL' first */
return (int) ((a->optimize & KEY_OPTIMIZE_REF_OR_NULL) -
(b->optimize & KEY_OPTIMIZE_REF_OR_NULL));
}
/*
Update keyuse array with all possible keys we can use to fetch rows
SYNOPSIS
update_ref_and_keys()
thd
keyuse OUT Put here ordered array of KEYUSE structures
join_tab Array in tablenr_order
tables Number of tables in join
cond WHERE condition (note that the function analyzes
join_tab[i]->on_expr too)
normal_tables tables not inner w.r.t some outer join (ones for which
we can make ref access based the WHERE clause)
select_lex current SELECT
RETURN
0 - OK
1 - Out of memory.
*/
static bool
update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
uint tables, COND *cond, table_map normal_tables,
SELECT_LEX *select_lex)
{
uint and_level,i,found_eq_constant;
KEY_FIELD *key_fields, *end, *field;
if (!(key_fields=(KEY_FIELD*)
thd->alloc(sizeof(key_fields[0])*
(thd->lex->current_select->cond_count+1)*2)))
return TRUE; /* purecov: inspected */
and_level= 0;
field= end= key_fields;
if (my_init_dynamic_array(keyuse,sizeof(KEYUSE),20,64))
return TRUE;
if (cond)
{
add_key_fields(&end,&and_level,cond,normal_tables);
for (; field != end ; field++)
{
add_key_part(keyuse,field);
/* Mark that we can optimize LEFT JOIN */
if (field->val->type() == Item::NULL_ITEM &&
!field->field->real_maybe_null())
field->field->table->reginfo.not_exists_optimize=1;
}
}
for (i=0 ; i < tables ; i++)
{
if (join_tab[i].on_expr)
{
add_key_fields(&end,&and_level,join_tab[i].on_expr,
join_tab[i].table->map);
}
}
/* fill keyuse with found key parts */
for ( ; field != end ; field++)
add_key_part(keyuse,field);
if (select_lex->ftfunc_list->elements)
{
add_ft_keys(keyuse,join_tab,cond,normal_tables);
}
/*
Special treatment for ft-keys.
Remove the following things from KEYUSE:
- ref if there is a keypart which is a ref and a const.
- keyparts without previous keyparts.
*/
if (keyuse->elements)
{
KEYUSE end,*prev,*save_pos,*use;
qsort(keyuse->buffer,keyuse->elements,sizeof(KEYUSE),
(qsort_cmp) sort_keyuse);
bzero((char*) &end,sizeof(end)); /* Add for easy testing */
VOID(insert_dynamic(keyuse,(gptr) &end));
use=save_pos=dynamic_element(keyuse,0,KEYUSE*);
prev=&end;
found_eq_constant=0;
for (i=0 ; i < keyuse->elements-1 ; i++,use++)
{
if (!use->used_tables)
use->table->const_key_parts[use->key]|= use->keypart_map;
if (use->keypart != FT_KEYPART)
{
if (use->key == prev->key && use->table == prev->table)
{
if (prev->keypart+1 < use->keypart ||
prev->keypart == use->keypart && found_eq_constant)
continue; /* remove */
}
else if (use->keypart != 0) // First found must be 0
continue;
}
*save_pos= *use;
prev=use;
found_eq_constant= !use->used_tables;
/* Save ptr to first use */
if (!use->table->reginfo.join_tab->keyuse)
use->table->reginfo.join_tab->keyuse=save_pos;
use->table->reginfo.join_tab->checked_keys.set_bit(use->key);
save_pos++;
}
i=(uint) (save_pos-(KEYUSE*) keyuse->buffer);
VOID(set_dynamic(keyuse,(gptr) &end,i));
keyuse->elements=i;
}
return FALSE;
}
/*
Update some values in keyuse for faster find_best_combination() loop
*/
static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array)
{
KEYUSE *end,*keyuse= dynamic_element(keyuse_array, 0, KEYUSE*);
for (end= keyuse+ keyuse_array->elements ; keyuse < end ; keyuse++)
{
table_map map;
/*
If we find a ref, assume this table matches a proportional
part of this table.
For example 100 records matching a table with 5000 records
gives 5000/100 = 50 records per key
Constant tables are ignored.
To avoid bad matches, we don't make ref_table_rows less than 100.
*/
keyuse->ref_table_rows= ~(ha_rows) 0; // If no ref
if (keyuse->used_tables &
(map= (keyuse->used_tables & ~join->const_table_map &
~OUTER_REF_TABLE_BIT)))
{
uint tablenr;
for (tablenr=0 ; ! (map & 1) ; map>>=1, tablenr++) ;
if (map == 1) // Only one table
{
TABLE *tmp_table=join->all_tables[tablenr];
keyuse->ref_table_rows= max(tmp_table->file->records, 100);
}
}
/*
Outer reference (external field) is constant for single executing
of subquery
*/
if (keyuse->used_tables == OUTER_REF_TABLE_BIT)
keyuse->ref_table_rows= 1;
}
}
/*****************************************************************************
Go through all combinations of not marked tables and find the one
which uses least records
*****************************************************************************/
/* Save const tables first as used tables */
static void
set_position(JOIN *join,uint idx,JOIN_TAB *table,KEYUSE *key)
{
join->positions[idx].table= table;
join->positions[idx].key=key;
join->positions[idx].records_read=1.0; /* This is a const table */
/* Move the const table as down as possible in best_ref */
JOIN_TAB **pos=join->best_ref+idx+1;
JOIN_TAB *next=join->best_ref[idx];
for (;next != table ; pos++)
{
JOIN_TAB *tmp=pos[0];
pos[0]=next;
next=tmp;
}
join->best_ref[idx]=table;
}
static void
find_best_combination(JOIN *join, table_map rest_tables)
{
DBUG_ENTER("find_best_combination");
join->best_read=DBL_MAX;
find_best(join,rest_tables, join->const_tables,1.0,0.0);
DBUG_VOID_RETURN;
}
static void
find_best(JOIN *join,table_map rest_tables,uint idx,double record_count,
double read_time)
{
ha_rows rec;
double tmp;
THD *thd= join->thd;
if (!rest_tables)
{
DBUG_PRINT("best",("read_time: %g record_count: %g",read_time,
record_count));
read_time+=record_count/(double) TIME_FOR_COMPARE;
if (join->sort_by_table &&
join->sort_by_table !=
join->positions[join->const_tables].table->table)
read_time+=record_count; // We have to make a temp table
if (read_time < join->best_read)
{
memcpy((gptr) join->best_positions,(gptr) join->positions,
sizeof(POSITION)*idx);
join->best_read=read_time;
}
return;
}
if (read_time+record_count/(double) TIME_FOR_COMPARE >= join->best_read)
return; /* Found better before */
JOIN_TAB *s;
double best_record_count=DBL_MAX,best_read_time=DBL_MAX;
for (JOIN_TAB **pos=join->best_ref+idx ; (s=*pos) ; pos++)
{
table_map real_table_bit=s->table->map;
if ((rest_tables & real_table_bit) && !(rest_tables & s->dependent))
{
double best,best_time,records;
best=best_time=records=DBL_MAX;
KEYUSE *best_key=0;
uint best_max_key_part=0;
my_bool found_constraint= 0;
if (s->keyuse)
{ /* Use key if possible */
TABLE *table=s->table;
KEYUSE *keyuse,*start_key=0;
double best_records=DBL_MAX;
uint max_key_part=0;
/* Test how we can use keys */
rec= s->records/MATCHING_ROWS_IN_OTHER_TABLE; // Assumed records/key
for (keyuse=s->keyuse ; keyuse->table == table ;)
{
key_part_map found_part=0;
table_map found_ref=0;
uint key=keyuse->key;
KEY *keyinfo=table->key_info+key;
bool ft_key=(keyuse->keypart == FT_KEYPART);
uint found_ref_or_null= 0;
/* Calculate how many key segments of the current key we can use */
start_key=keyuse;
do
{
uint keypart=keyuse->keypart;
table_map best_part_found_ref= 0;
double best_prev_record_reads= DBL_MAX;
do
{
if (!(rest_tables & keyuse->used_tables) &&
!(found_ref_or_null & keyuse->optimize))
{
found_part|=keyuse->keypart_map;
double tmp= prev_record_reads(join,
(found_ref |
keyuse->used_tables));
if (tmp < best_prev_record_reads)
{
best_part_found_ref= keyuse->used_tables;
best_prev_record_reads= tmp;
}
if (rec > keyuse->ref_table_rows)
rec= keyuse->ref_table_rows;
/*
If there is one 'key_column IS NULL' expression, we can
use this ref_or_null optimisation of this field
*/
found_ref_or_null|= (keyuse->optimize &
KEY_OPTIMIZE_REF_OR_NULL);
}
keyuse++;
} while (keyuse->table == table && keyuse->key == key &&
keyuse->keypart == keypart);
found_ref|= best_part_found_ref;
} while (keyuse->table == table && keyuse->key == key);
/*
Assume that that each key matches a proportional part of table.
*/
if (!found_part && !ft_key)
continue; // Nothing usable found
if (rec < MATCHING_ROWS_IN_OTHER_TABLE)
rec= MATCHING_ROWS_IN_OTHER_TABLE; // Fix for small tables
/*
ft-keys require special treatment
*/
if (ft_key)
{
/*
Really, there should be records=0.0 (yes!)
but 1.0 would be probably safer
*/
tmp=prev_record_reads(join,found_ref);
records=1.0;
}
else
{
found_constraint= 1;
/*
Check if we found full key
*/
if (found_part == PREV_BITS(uint,keyinfo->key_parts) &&
!found_ref_or_null)
{ /* use eq key */
max_key_part= (uint) ~0;
if ((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY |
HA_END_SPACE_KEY)) == HA_NOSAME)
{
tmp=prev_record_reads(join,found_ref);
records=1.0;
}
else
{
if (!found_ref)
{ // We found a const key
if (table->quick_keys.is_set(key))
records= (double) table->quick_rows[key];
else
{
/* quick_range couldn't use key! */
records= (double) s->records/rec;
}
}
else
{
if (!(records=keyinfo->rec_per_key[keyinfo->key_parts-1]))
{ // Prefere longer keys
records=
((double) s->records / (double) rec *
(1.0 +
((double) (table->max_key_length-keyinfo->key_length) /
(double) table->max_key_length)));
if (records < 2.0)
records=2.0; // Can't be as good as a unique
}
}
/* Limit the number of matched rows */
tmp= records;
set_if_smaller(tmp, (double) thd->variables.max_seeks_for_key);
if (table->used_keys.is_set(key))
{
/* we can use only index tree */
uint keys_per_block= table->file->block_size/2/
(keyinfo->key_length+table->file->ref_length)+1;
tmp=record_count*(tmp+keys_per_block-1)/keys_per_block;
}
else
tmp=record_count*min(tmp,s->worst_seeks);
}
}
else
{
/*
Use as much key-parts as possible and a uniq key is better
than a not unique key
Set tmp to (previous record count) * (records / combination)
*/
if ((found_part & 1) &&
(!(table->file->index_flags(key,0,0) & HA_ONLY_WHOLE_INDEX) ||
found_part == PREV_BITS(uint,keyinfo->key_parts)))
{
max_key_part=max_part_bit(found_part);
/*
Check if quick_range could determinate how many rows we
will match
*/
if (table->quick_keys.is_set(key) &&
table->quick_key_parts[key] == max_key_part)
tmp=records= (double) table->quick_rows[key];
else
{
/* Check if we have statistic about the distribution */
if ((records=keyinfo->rec_per_key[max_key_part-1]))
tmp=records;
else
{
/*
Assume that the first key part matches 1% of the file
and that the hole key matches 10 (duplicates) or 1
(unique) records.
Assume also that more key matches proportionally more
records
This gives the formula:
records= (x * (b-a) + a*c-b)/(c-1)
b = records matched by whole key
a = records matched by first key part (10% of all records?)
c = number of key parts in key
x = used key parts (1 <= x <= c)
*/
double rec_per_key;
rec_per_key= keyinfo->rec_per_key[keyinfo->key_parts-1] ?
(double) keyinfo->rec_per_key[keyinfo->key_parts-1] :
(double) s->records/rec+1;
if (!s->records)
tmp=0;
else if (rec_per_key/(double) s->records >= 0.01)
tmp=rec_per_key;
else
{
double a=s->records*0.01;
tmp=(max_key_part * (rec_per_key - a) +
a*keyinfo->key_parts - rec_per_key)/
(keyinfo->key_parts-1);
set_if_bigger(tmp,1.0);
}
records=(ulong) tmp;
}
/*
If quick_select was used on a part of this key, we know
the maximum number of rows that the key can match.
*/
if (table->quick_keys.is_set(key) &&
table->quick_key_parts[key] <= max_key_part &&
records > (double) table->quick_rows[key])
tmp= records= (double) table->quick_rows[key];
else if (found_ref_or_null)
{
/* We need to do two key searches to find key */
tmp*= 2.0;
records*= 2.0;
}
}
/* Limit the number of matched rows */
set_if_smaller(tmp, (double) thd->variables.max_seeks_for_key);
if (table->used_keys.is_set(key))
{
/* we can use only index tree */
uint keys_per_block= table->file->block_size/2/
(keyinfo->key_length+table->file->ref_length)+1;
tmp=record_count*(tmp+keys_per_block-1)/keys_per_block;
}
else
tmp=record_count*min(tmp,s->worst_seeks);
}
else
tmp=best_time; // Do nothing
}
} /* not ft_key */
if (tmp < best_time - records/(double) TIME_FOR_COMPARE)
{
best_time=tmp + records/(double) TIME_FOR_COMPARE;
best=tmp;
best_records=records;
best_key=start_key;
best_max_key_part=max_key_part;
}
}
records=best_records;
}
/*
Don't test table scan if it can't be better.
Prefer key lookup if we would use the same key for scanning.
Don't do a table scan on InnoDB tables, if we can read the used
parts of the row from any of the used index.
This is because table scans uses index and we would not win
anything by using a table scan.
*/
if ((records >= s->found_records || best > s->read_time) &&
!(s->quick && best_key && s->quick->index == best_key->key &&
best_max_key_part >= s->table->quick_key_parts[best_key->key]) &&
!((s->table->file->table_flags() & HA_TABLE_SCAN_ON_INDEX) &&
! s->table->used_keys.is_clear_all() && best_key) &&
!(s->table->force_index && best_key))
{ // Check full join
ha_rows rnd_records= s->found_records;
/*
If there is a restriction on the table, assume that 25% of the
rows can be skipped on next part.
This is to force tables that this table depends on before this
table
*/
if (found_constraint)
rnd_records-= rnd_records/4;
/*
Range optimizer never proposes a RANGE if it isn't better
than FULL: so if RANGE is present, it's always preferred to FULL.
Here we estimate its cost.
*/
if (s->quick)
{
/*
For each record we:
- read record range through 'quick'
- skip rows which does not satisfy WHERE constraints
*/
tmp= record_count *
(s->quick->read_time +
(s->found_records - rnd_records)/(double) TIME_FOR_COMPARE);
}
else
{
/* Estimate cost of reading table. */
tmp= s->table->file->scan_time();
if (s->on_expr) // Can't use join cache
{
/*
For each record we have to:
- read the whole table record
- skip rows which does not satisfy join condition
*/
tmp= record_count *
(tmp +
(s->records - rnd_records)/(double) TIME_FOR_COMPARE);
}
else
{
/* We read the table as many times as join buffer becomes full. */
tmp*= (1.0 + floor((double) cache_record_length(join,idx) *
record_count /
(double) thd->variables.join_buff_size));
/*
We don't make full cartesian product between rows in the scanned
table and existing records because we skip all rows from the
scanned table, which does not satisfy join condition when
we read the table (see flush_cached_records for details). Here we
take into account cost to read and skip these records.
*/
tmp+= (s->records - rnd_records)/(double) TIME_FOR_COMPARE;
}
}
/*
We estimate the cost of evaluating WHERE clause for found records
as record_count * rnd_records / TIME_FOR_COMPARE. This cost plus
tmp give us total cost of using TABLE SCAN
*/
if (best == DBL_MAX ||
(tmp + record_count/(double) TIME_FOR_COMPARE*rnd_records <
best + record_count/(double) TIME_FOR_COMPARE*records))
{
/*
If the table has a range (s->quick is set) make_join_select()
will ensure that this will be used
*/
best=tmp;
records= rows2double(rnd_records);
best_key=0;
}
}
join->positions[idx].records_read= records;
join->positions[idx].key=best_key;
join->positions[idx].table= s;
if (!best_key && idx == join->const_tables &&
s->table == join->sort_by_table &&
join->unit->select_limit_cnt >= records)
join->sort_by_table= (TABLE*) 1; // Must use temporary table
/*
Go to the next level only if there hasn't been a better key on
this level! This will cut down the search for a lot simple cases!
*/
double current_record_count=record_count*records;
double current_read_time=read_time+best;
if (best_record_count > current_record_count ||
best_read_time > current_read_time ||
idx == join->const_tables && s->table == join->sort_by_table)
{
if (best_record_count >= current_record_count &&
best_read_time >= current_read_time &&
(!(s->key_dependent & rest_tables) || records < 2.0))
{
best_record_count=current_record_count;
best_read_time=current_read_time;
}
swap_variables(JOIN_TAB*, join->best_ref[idx], *pos);
find_best(join,rest_tables & ~real_table_bit,idx+1,
current_record_count,current_read_time);
if (thd->killed)
return;
swap_variables(JOIN_TAB*, join->best_ref[idx], *pos);
}
if (join->select_options & SELECT_STRAIGHT_JOIN)
break; // Don't test all combinations
}
}
}
/*
Find how much space the prevous read not const tables takes in cache
*/
static void calc_used_field_length(THD *thd, JOIN_TAB *join_tab)
{
uint null_fields,blobs,fields,rec_length;
null_fields=blobs=fields=rec_length=0;
Field **f_ptr,*field;
for (f_ptr=join_tab->table->field ; (field= *f_ptr) ; f_ptr++)
{
if (field->query_id == thd->query_id)
{
uint flags=field->flags;
fields++;
rec_length+=field->pack_length();
if (flags & BLOB_FLAG)
blobs++;
if (!(flags & NOT_NULL_FLAG))
null_fields++;
}
}
if (null_fields)
rec_length+=(join_tab->table->null_fields+7)/8;
if (join_tab->table->maybe_null)
rec_length+=sizeof(my_bool);
if (blobs)
{
uint blob_length=(uint) (join_tab->table->file->mean_rec_length-
(join_tab->table->reclength- rec_length));
rec_length+=(uint) max(4,blob_length);
}
join_tab->used_fields=fields;
join_tab->used_fieldlength=rec_length;
join_tab->used_blobs=blobs;
}
static uint
cache_record_length(JOIN *join,uint idx)
{
uint length=0;
JOIN_TAB **pos,**end;
THD *thd=join->thd;
for (pos=join->best_ref+join->const_tables,end=join->best_ref+idx ;
pos != end ;
pos++)
{
JOIN_TAB *join_tab= *pos;
if (!join_tab->used_fieldlength) /* Not calced yet */
calc_used_field_length(thd, join_tab);
length+=join_tab->used_fieldlength;
}
return length;
}
static double
prev_record_reads(JOIN *join,table_map found_ref)
{
double found=1.0;
found_ref&= ~OUTER_REF_TABLE_BIT;
for (POSITION *pos=join->positions ; found_ref ; pos++)
{
if (pos->table->table->map & found_ref)
{
found_ref&= ~pos->table->table->map;
found*=pos->records_read;
}
}
return found;
}
/*****************************************************************************
Set up join struct according to best position.
*****************************************************************************/
static bool
get_best_combination(JOIN *join)
{
uint i,tablenr;
table_map used_tables;
JOIN_TAB *join_tab,*j;
KEYUSE *keyuse;
uint table_count;
THD *thd=join->thd;
table_count=join->tables;
if (!(join->join_tab=join_tab=
(JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB)*table_count)))
return TRUE;
join->full_join=0;
used_tables= OUTER_REF_TABLE_BIT; // Outer row is already read
for (j=join_tab, tablenr=0 ; tablenr < table_count ; tablenr++,j++)
{
TABLE *form;
*j= *join->best_positions[tablenr].table;
form=join->table[tablenr]=j->table;
used_tables|= form->map;
form->reginfo.join_tab=j;
if (!j->on_expr)
form->reginfo.not_exists_optimize=0; // Only with LEFT JOIN
if (j->type == JT_CONST)
continue; // Handled in make_join_stat..
j->ref.key = -1;
j->ref.key_parts=0;
if (j->type == JT_SYSTEM)
continue;
if (j->keys.is_clear_all() || !(keyuse= join->best_positions[tablenr].key))
{
j->type=JT_ALL;
if (tablenr != join->const_tables)
join->full_join=1;
}
else if (create_ref_for_key(join, j, keyuse, used_tables))
return TRUE; // Something went wrong
}
for (i=0 ; i < table_count ; i++)
join->map2table[join->join_tab[i].table->tablenr]=join->join_tab+i;
update_depend_map(join);
return 0;
}
static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
table_map used_tables)
{
KEYUSE *keyuse=org_keyuse;
bool ftkey=(keyuse->keypart == FT_KEYPART);
THD *thd= join->thd;
uint keyparts,length,key;
TABLE *table;
KEY *keyinfo;
/* Use best key from find_best */
table=j->table;
key=keyuse->key;
keyinfo=table->key_info+key;
if (ftkey)
{
Item_func_match *ifm=(Item_func_match *)keyuse->val;
length=0;
keyparts=1;
ifm->join_key=1;
}
else
{
keyparts=length=0;
uint found_part_ref_or_null= 0;
/*
Calculate length for the used key
Stop if there is a missing key part or when we find second key_part
with KEY_OPTIMIZE_REF_OR_NULL
*/
do
{
if (!(~used_tables & keyuse->used_tables))
{
if (keyparts == keyuse->keypart &&
!(found_part_ref_or_null & keyuse->optimize))
{
keyparts++;
length+= keyinfo->key_part[keyuse->keypart].store_length;
found_part_ref_or_null|= keyuse->optimize;
}
}
keyuse++;
} while (keyuse->table == table && keyuse->key == key);
} /* not ftkey */
/* set up fieldref */
keyinfo=table->key_info+key;
j->ref.key_parts=keyparts;
j->ref.key_length=length;
j->ref.key=(int) key;
if (!(j->ref.key_buff= (byte*) thd->calloc(ALIGN_SIZE(length)*2)) ||
!(j->ref.key_copy= (store_key**) thd->alloc((sizeof(store_key*) *
(keyparts+1)))) ||
!(j->ref.items= (Item**) thd->alloc(sizeof(Item*)*keyparts)))
{
return TRUE;
}
j->ref.key_buff2=j->ref.key_buff+ALIGN_SIZE(length);
j->ref.key_err=1;
j->ref.null_rejecting= 0;
keyuse=org_keyuse;
store_key **ref_key= j->ref.key_copy;
byte *key_buff=j->ref.key_buff, *null_ref_key= 0;
bool keyuse_uses_no_tables= TRUE;
if (ftkey)
{
j->ref.items[0]=((Item_func*)(keyuse->val))->key_item();
if (keyuse->used_tables)
return TRUE; // not supported yet. SerG
j->type=JT_FT;
}
else
{
uint i;
for (i=0 ; i < keyparts ; keyuse++,i++)
{
while (keyuse->keypart != i ||
((~used_tables) & keyuse->used_tables))
keyuse++; /* Skip other parts */
uint maybe_null= test(keyinfo->key_part[i].null_bit);
j->ref.items[i]=keyuse->val; // Save for cond removal
if (keyuse->null_rejecting)
j->ref.null_rejecting |= 1 << i;
keyuse_uses_no_tables= keyuse_uses_no_tables && !keyuse->used_tables;
if (!keyuse->used_tables &&
!(join->select_options & SELECT_DESCRIBE))
{ // Compare against constant
store_key_item tmp(thd, keyinfo->key_part[i].field,
(char*)key_buff + maybe_null,
maybe_null ? (char*) key_buff : 0,
keyinfo->key_part[i].length, keyuse->val);
if (thd->is_fatal_error)
return TRUE;
tmp.copy();
}
else
*ref_key++= get_store_key(thd,
keyuse,join->const_table_map,
&keyinfo->key_part[i],
(char*) key_buff,maybe_null);
/*
Remeber if we are going to use REF_OR_NULL
But only if field _really_ can be null i.e. we force JT_REF
instead of JT_REF_OR_NULL in case if field can't be null
*/
if ((keyuse->optimize & KEY_OPTIMIZE_REF_OR_NULL) && maybe_null)
null_ref_key= key_buff;
key_buff+=keyinfo->key_part[i].store_length;
}
} /* not ftkey */
*ref_key=0; // end_marker
if (j->type == JT_FT)
return 0;
if (j->type == JT_CONST)
j->table->const_table= 1;
else if (((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY |
HA_END_SPACE_KEY)) != HA_NOSAME) ||
keyparts != keyinfo->key_parts || null_ref_key)
{
/* Must read with repeat */
j->type= null_ref_key ? JT_REF_OR_NULL : JT_REF;
j->ref.null_ref_key= null_ref_key;
}
else if (keyuse_uses_no_tables)
{
/*
This happen if we are using a constant expression in the ON part
of an LEFT JOIN.
SELECT * FROM a LEFT JOIN b ON b.key=30
Here we should not mark the table as a 'const' as a field may
have a 'normal' value or a NULL value.
*/
j->type=JT_CONST;
}
else
j->type=JT_EQ_REF;
return 0;
}
static store_key *
get_store_key(THD *thd, KEYUSE *keyuse, table_map used_tables,
KEY_PART_INFO *key_part, char *key_buff, uint maybe_null)
{
if (!((~used_tables) & keyuse->used_tables)) // if const item
{
return new store_key_const_item(thd,
key_part->field,
key_buff + maybe_null,
maybe_null ? key_buff : 0,
key_part->length,
keyuse->val);
}
else if (keyuse->val->type() == Item::FIELD_ITEM)
return new store_key_field(thd,
key_part->field,
key_buff + maybe_null,
maybe_null ? key_buff : 0,
key_part->length,
((Item_field*) keyuse->val)->field,
keyuse->val->full_name());
return new store_key_item(thd,
key_part->field,
key_buff + maybe_null,
maybe_null ? key_buff : 0,
key_part->length,
keyuse->val);
}
/*
This function is only called for const items on fields which are keys
returns 1 if there was some conversion made when the field was stored.
*/
bool
store_val_in_field(Field *field, Item *item, enum_check_fields check_flag)
{
bool error;
THD *thd=current_thd;
ha_rows cuted_fields=thd->cuted_fields;
/*
we should restore old value of count_cuted_fields because
store_val_in_field can be called from mysql_insert
with select_insert, which make count_cuted_fields= 1
*/
enum_check_fields old_count_cuted_fields= thd->count_cuted_fields;
thd->count_cuted_fields= check_flag;
error= item->save_in_field(field, 1);
thd->count_cuted_fields= old_count_cuted_fields;
return error || cuted_fields != thd->cuted_fields;
}
static bool
make_simple_join(JOIN *join,TABLE *tmp_table)
{
TABLE **tableptr;
JOIN_TAB *join_tab;
if (!(tableptr=(TABLE**) join->thd->alloc(sizeof(TABLE*))) ||
!(join_tab=(JOIN_TAB*) join->thd->alloc(sizeof(JOIN_TAB))))
return TRUE;
join->join_tab=join_tab;
join->table=tableptr; tableptr[0]=tmp_table;
join->tables=1;
join->const_tables=0;
join->const_table_map=0;
join->tmp_table_param.field_count= join->tmp_table_param.sum_func_count=
join->tmp_table_param.func_count=0;
join->tmp_table_param.copy_field=join->tmp_table_param.copy_field_end=0;
join->first_record=join->sort_and_group=0;
join->send_records=(ha_rows) 0;
join->group=0;
join->row_limit=join->unit->select_limit_cnt;
join->do_send_rows = (join->row_limit) ? 1 : 0;
join_tab->cache.buff=0; /* No caching */
join_tab->table=tmp_table;
join_tab->select=0;
join_tab->select_cond=0;
join_tab->quick=0;
join_tab->type= JT_ALL; /* Map through all records */
join_tab->keys.init();
join_tab->keys.set_all(); /* test everything in quick */
join_tab->info=0;
join_tab->on_expr=0;
join_tab->ref.key = -1;
join_tab->not_used_in_distinct=0;
join_tab->read_first_record= join_init_read_record;
join_tab->join=join;
bzero((char*) &join_tab->read_record,sizeof(join_tab->read_record));
tmp_table->status=0;
tmp_table->null_row=0;
return FALSE;
}
inline void add_cond_and_fix(Item **e1, Item *e2)
{
if (*e1)
{
Item *res;
if ((res= new Item_cond_and(*e1, e2)))
{
*e1= res;
res->quick_fix_field();
}
}
else
*e1= e2;
}
/*
Add to join_tab->select_cond[i] "table.field IS NOT NULL" conditions we've
inferred from ref/eq_ref access performed.
SYNOPSIS
add_not_null_conds()
join Join to process
NOTES
This function is a part of "Early NULL-values filtering for ref access"
optimization.
Example of this optimization:
For query SELECT * FROM t1,t2 WHERE t2.key=t1.field
and plan " any-access(t1), ref(t2.key=t1.field) "
add "t1.field IS NOT NULL" to t1's table condition.
Description of the optimization:
We look through equalities choosen to perform ref/eq_ref access,
pick equalities that have form "tbl.part_of_key = othertbl.field"
(where othertbl is a non-const table and othertbl.field may be NULL)
and add them to conditions on correspoding tables (othertbl in this
example).
Exception from that is the case when referred_tab->join != join.
I.e. don't add NOT NULL constraints from any embedded subquery.
Consider this query:
SELECT A.f2 FROM t1 LEFT JOIN t2 A ON A.f2 = f1
WHERE A.f3=(SELECT MIN(f3) FROM t2 C WHERE A.f4 = C.f4) OR A.f3 IS NULL;
Here condition A.f3 IS NOT NULL is going to be added to the WHERE
condition of the embedding query.
Another example:
SELECT * FROM t10, t11 WHERE (t10.a < 10 OR t10.a IS NULL)
AND t11.b <=> t10.b AND (t11.a = (SELECT MAX(a) FROM t12
WHERE t12.b = t10.a ));
Here condition t10.a IS NOT NULL is going to be added.
In both cases addition of NOT NULL condition will erroneously reject
some rows of the result set.
referred_tab->join != join constraint would disallow such additions.
This optimization doesn't affect the choices that ref, range, or join
optimizer make. This was intentional because this was added after 4.1
was GA.
Implementation overview
1. update_ref_and_keys() accumulates info about null-rejecting
predicates in in KEY_FIELD::null_rejecting
1.1 add_key_part saves these to KEYUSE.
2. create_ref_for_key copies them to TABLE_REF.
3. add_not_null_conds adds "x IS NOT NULL" to join_tab->select_cond of
appropiate JOIN_TAB members.
*/
static void add_not_null_conds(JOIN *join)
{
DBUG_ENTER("add_not_null_conds");
for (uint i=join->const_tables ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
if ((tab->type == JT_REF || tab->type == JT_REF_OR_NULL) &&
!tab->table->maybe_null)
{
for (uint keypart= 0; keypart < tab->ref.key_parts; keypart++)
{
if (tab->ref.null_rejecting & (1 << keypart))
{
Item *item= tab->ref.items[keypart];
Item *notnull;
DBUG_ASSERT(item->type() == Item::FIELD_ITEM);
Item_field *not_null_item= (Item_field*)item;
JOIN_TAB *referred_tab= not_null_item->field->table->reginfo.join_tab;
/*
For UPDATE queries such as:
UPDATE t1 SET t1.f2=(SELECT MAX(t2.f4) FROM t2 WHERE t2.f3=t1.f1);
not_null_item is the t1.f1, but it's referred_tab is 0.
*/
if (!referred_tab || referred_tab->join != join)
continue;
if (!(notnull= new Item_func_isnotnull(not_null_item)))
DBUG_VOID_RETURN;
/*
We need to do full fix_fields() call here in order to have correct
notnull->const_item(). This is needed e.g. by test_quick_select
when it is called from make_join_select after this function is
called.
*/
if (notnull->fix_fields(join->thd, join->tables_list, &notnull))
DBUG_VOID_RETURN;
DBUG_EXECUTE("where",print_where(notnull,
referred_tab->table->table_name););
add_cond_and_fix(&referred_tab->select_cond, notnull);
}
}
}
}
DBUG_VOID_RETURN;
}
static bool
make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
{
DBUG_ENTER("make_join_select");
if (select)
{
add_not_null_conds(join);
table_map used_tables;
if (join->tables > 1)
cond->update_used_tables(); // Tablenr may have changed
if (join->const_tables == join->tables &&
join->thd->lex->current_select->master_unit() ==
&join->thd->lex->unit) // not upper level SELECT
join->const_table_map|=RAND_TABLE_BIT;
{ // Check const tables
COND *const_cond=
make_cond_for_table(cond,join->const_table_map,(table_map) 0);
DBUG_EXECUTE("where",print_where(const_cond,"constants"););
if (const_cond && !const_cond->val_int())
{
DBUG_PRINT("info",("Found impossible WHERE condition"));
DBUG_RETURN(1); // Impossible const condition
}
}
used_tables=((select->const_tables=join->const_table_map) |
OUTER_REF_TABLE_BIT | RAND_TABLE_BIT);
for (uint i=join->const_tables ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
table_map current_map= tab->table->map;
/*
Following force including random expression in last table condition.
It solve problem with select like SELECT * FROM t1 WHERE rand() > 0.5
*/
if (i == join->tables-1)
current_map|= OUTER_REF_TABLE_BIT | RAND_TABLE_BIT;
bool use_quick_range=0;
used_tables|=current_map;
if (tab->type == JT_REF && tab->quick &&
(uint) tab->ref.key == tab->quick->index &&
tab->ref.key_length < tab->quick->max_used_key_length)
{
/* Range uses longer key; Use this instead of ref on key */
tab->type=JT_ALL;
use_quick_range=1;
tab->use_quick=1;
tab->ref.key= -1;
tab->ref.key_parts=0; // Don't use ref key.
join->best_positions[i].records_read= rows2double(tab->quick->records);
}
COND *tmp=make_cond_for_table(cond,used_tables,current_map);
if (!tmp && tab->quick)
{ // Outer join
/*
Hack to handle the case where we only refer to a table
in the ON part of an OUTER JOIN.
*/
tmp=new Item_int((longlong) 1,1); // Always true
}
if (tmp)
{
SQL_SELECT *sel=tab->select=(SQL_SELECT*)
join->thd->memdup((gptr) select, sizeof(SQL_SELECT));
if (!sel)
DBUG_RETURN(1); // End of memory
add_cond_and_fix(&tab->select_cond, tmp);
sel->cond= tab->select_cond;
sel->head=tab->table;
DBUG_EXECUTE("where",print_where(tmp,tab->table->table_name););
if (tab->quick)
{
/* Use quick key read if it's a constant and it's not used
with key reading */
if (tab->needed_reg.is_clear_all() && tab->type != JT_EQ_REF
&& tab->type != JT_FT && (tab->type != JT_REF ||
(uint) tab->ref.key == tab->quick->index))
{
sel->quick=tab->quick; // Use value from get_quick_...
sel->quick_keys.clear_all();
sel->needed_reg.clear_all();
}
else
{
delete tab->quick;
}
tab->quick=0;
}
uint ref_key=(uint) sel->head->reginfo.join_tab->ref.key+1;
if (i == join->const_tables && ref_key)
{
if (!tab->const_keys.is_clear_all() &&
tab->table->reginfo.impossible_range)
DBUG_RETURN(1);
}
else if (tab->type == JT_ALL && ! use_quick_range)
{
if (!tab->const_keys.is_clear_all() &&
tab->table->reginfo.impossible_range)
DBUG_RETURN(1); // Impossible range
/*
We plan to scan all rows.
Check again if we should use an index.
We could have used an column from a previous table in
the index if we are using limit and this is the first table
*/
if ((!tab->keys.is_subset(tab->const_keys) && i > 0) ||
(!tab->const_keys.is_clear_all() && i == join->const_tables &&
join->unit->select_limit_cnt <
join->best_positions[i].records_read &&
!(join->select_options & OPTION_FOUND_ROWS)))
{
/* Join with outer join condition */
COND *orig_cond=sel->cond;
sel->cond= and_conds(sel->cond, tab->on_expr);
/*
We can't call sel->cond->fix_fields,
as it will break tab->on_expr if it's AND condition
(fix_fields currently removes extra AND/OR levels).
Yet attributes of the just built condition are not needed.
Thus we call sel->cond->quick_fix_field for safety.
*/
if (sel->cond && !sel->cond->fixed)
sel->cond->quick_fix_field();
if (sel->test_quick_select(join->thd, tab->keys,
used_tables & ~ current_map,
(join->select_options &
OPTION_FOUND_ROWS ?
HA_POS_ERROR :
join->unit->select_limit_cnt), 0) < 0)
{
/*
Before reporting "Impossible WHERE" for the whole query
we have to check isn't it only "impossible ON" instead
*/
sel->cond=orig_cond;
if (!tab->on_expr ||
sel->test_quick_select(join->thd, tab->keys,
used_tables & ~ current_map,
(join->select_options &
OPTION_FOUND_ROWS ?
HA_POS_ERROR :
join->unit->select_limit_cnt),0) < 0)
DBUG_RETURN(1); // Impossible WHERE
}
else
sel->cond=orig_cond;
/* Fix for EXPLAIN */
if (sel->quick)
join->best_positions[i].records_read= sel->quick->records;
}
else
{
sel->needed_reg=tab->needed_reg;
sel->quick_keys.clear_all();
}
if (!sel->quick_keys.is_subset(tab->checked_keys) ||
!sel->needed_reg.is_subset(tab->checked_keys))
{
tab->keys=sel->quick_keys;
tab->keys.merge(sel->needed_reg);
tab->use_quick= (!sel->needed_reg.is_clear_all() &&
(select->quick_keys.is_clear_all() ||
(select->quick &&
(select->quick->records >= 100L)))) ?
2 : 1;
sel->read_tables= used_tables & ~current_map;
}
if (i != join->const_tables && tab->use_quick != 2)
{ /* Read with cache */
if ((tmp=make_cond_for_table(cond,
join->const_table_map |
current_map,
current_map)))
{
DBUG_EXECUTE("where",print_where(tmp,"cache"););
tab->cache.select=(SQL_SELECT*)
join->thd->memdup((gptr) sel, sizeof(SQL_SELECT));
tab->cache.select->cond=tmp;
tab->cache.select->read_tables=join->const_table_map;
}
}
}
}
}
}
DBUG_RETURN(0);
}
static void
make_join_readinfo(JOIN *join, uint options)
{
uint i;
bool statistics= test(!(join->select_options & SELECT_DESCRIBE));
bool ordered_set= 0;
DBUG_ENTER("make_join_readinfo");
for (i=join->const_tables ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
TABLE *table=tab->table;
tab->read_record.table= table;
tab->read_record.file=table->file;
tab->next_select=sub_select; /* normal select */
/*
Determine if the set is already ordered for ORDER BY, so it can
disable join cache because it will change the ordering of the results.
Code handles sort table that is at any location (not only first after
the const tables) despite the fact that it's currently prohibited.
*/
if (!ordered_set &&
(table == join->sort_by_table &&
(!join->order || join->skip_sort_order ||
test_if_skip_sort_order(tab, join->order, join->select_limit,
1))
) ||
(join->sort_by_table == (TABLE *) 1 && i != join->const_tables))
ordered_set= 1;
switch (tab->type) {
case JT_SYSTEM: // Only happens with left join
table->status=STATUS_NO_RECORD;
tab->read_first_record= join_read_system;
tab->read_record.read_record= join_no_more_records;
break;
case JT_CONST: // Only happens with left join
table->status=STATUS_NO_RECORD;
tab->read_first_record= join_read_const;
tab->read_record.read_record= join_no_more_records;
if (table->used_keys.is_set(tab->ref.key) &&
!table->no_keyread)
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
break;
case JT_EQ_REF:
table->status=STATUS_NO_RECORD;
if (tab->select)
{
delete tab->select->quick;
tab->select->quick=0;
}
delete tab->quick;
tab->quick=0;
tab->read_first_record= join_read_key;
tab->read_record.read_record= join_no_more_records;
if (table->used_keys.is_set(tab->ref.key) &&
!table->no_keyread)
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
break;
case JT_REF_OR_NULL:
case JT_REF:
table->status=STATUS_NO_RECORD;
if (tab->select)
{
delete tab->select->quick;
tab->select->quick=0;
}
delete tab->quick;
tab->quick=0;
if (table->used_keys.is_set(tab->ref.key) &&
!table->no_keyread)
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
if (tab->type == JT_REF)
{
tab->read_first_record= join_read_always_key;
tab->read_record.read_record= join_read_next_same;
}
else
{
tab->read_first_record= join_read_always_key_or_null;
tab->read_record.read_record= join_read_next_same_or_null;
}
break;
case JT_FT:
table->status=STATUS_NO_RECORD;
tab->read_first_record= join_ft_read_first;
tab->read_record.read_record= join_ft_read_next;
break;
case JT_ALL:
/*
If previous table use cache
If the incoming data set is already sorted don't use cache.
*/
table->status=STATUS_NO_RECORD;
if (i != join->const_tables && !(options & SELECT_NO_JOIN_CACHE) &&
tab->use_quick != 2 && !tab->on_expr && !ordered_set)
{
if ((options & SELECT_DESCRIBE) ||
!join_init_cache(join->thd,join->join_tab+join->const_tables,
i-join->const_tables))
{
tab[-1].next_select=sub_select_cache; /* Patch previous */
}
}
/* These init changes read_record */
if (tab->use_quick == 2)
{
join->thd->server_status|=SERVER_QUERY_NO_GOOD_INDEX_USED;
tab->read_first_record= join_init_quick_read_record;
if (statistics)
statistic_increment(select_range_check_count, &LOCK_status);
}
else
{
tab->read_first_record= join_init_read_record;
if (i == join->const_tables)
{
if (tab->select && tab->select->quick)
{
if (statistics)
statistic_increment(select_range_count, &LOCK_status);
}
else
{
join->thd->server_status|=SERVER_QUERY_NO_INDEX_USED;
if (statistics)
statistic_increment(select_scan_count, &LOCK_status);
}
}
else
{
if (tab->select && tab->select->quick)
{
if (statistics)
statistic_increment(select_full_range_join_count, &LOCK_status);
}
else
{
join->thd->server_status|=SERVER_QUERY_NO_INDEX_USED;
if (statistics)
statistic_increment(select_full_join_count, &LOCK_status);
}
}
if (!table->no_keyread)
{
if (tab->select && tab->select->quick &&
table->used_keys.is_set(tab->select->quick->index))
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
else if (!table->used_keys.is_clear_all() &&
!(tab->select && tab->select->quick))
{ // Only read index tree
tab->index=find_shortest_key(table, & table->used_keys);
tab->read_first_record= join_read_first;
tab->type=JT_NEXT; // Read with index_first / index_next
}
}
}
break;
default:
DBUG_PRINT("error",("Table type %d found",tab->type)); /* purecov: deadcode */
break; /* purecov: deadcode */
case JT_UNKNOWN:
case JT_MAYBE_REF:
abort(); /* purecov: deadcode */
}
}
join->join_tab[join->tables-1].next_select=0; /* Set by do_select */
DBUG_VOID_RETURN;
}
/*
Give error if we some tables are done with a full join
SYNOPSIS
error_if_full_join()
join Join condition
USAGE
This is used by multi_table_update and multi_table_delete when running
in safe mode
RETURN VALUES
0 ok
1 Error (full join used)
*/
bool error_if_full_join(JOIN *join)
{
for (JOIN_TAB *tab=join->join_tab, *end=join->join_tab+join->tables;
tab < end;
tab++)
{
if (tab->type == JT_ALL && (!tab->select || !tab->select->quick))
{
my_error(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE,MYF(0));
return(1);
}
}
return(0);
}
/*
cleanup JOIN_TAB
SYNOPSIS
JOIN_TAB::cleanup()
*/
void JOIN_TAB::cleanup()
{
delete select;
select= 0;
delete quick;
quick= 0;
x_free(cache.buff);
cache.buff= 0;
if (table)
{
if (table->key_read)
{
table->key_read= 0;
table->file->extra(HA_EXTRA_NO_KEYREAD);
}
table->file->ha_index_or_rnd_end();
/*
We need to reset this for next select
(Tested in part_of_refkey)
*/
table->reginfo.join_tab= 0;
}
end_read_record(&read_record);
}
/*
Free resources of given join
SYNOPSIS
JOIN::join_free()
fill - true if we should free all resources, call with full==1 should be
last, before it this function can be called with full==0
NOTE: with subquery this function definitely will be called several times,
but even for simple query it can be called several times.
*/
void
JOIN::join_free(bool full)
{
JOIN_TAB *tab,*end;
DBUG_ENTER("JOIN::join_free");
full= full || (!select_lex->uncacheable &&
!thd->lex->subqueries &&
!thd->lex->describe); // do not cleanup too early on EXPLAIN
if (table)
{
/*
Only a sorted table may be cached. This sorted table is always the
first non const table in join->table
*/
if (tables > const_tables) // Test for not-const tables
{
free_io_cache(table[const_tables]);
filesort_free_buffers(table[const_tables]);
}
for (SELECT_LEX_UNIT *unit= select_lex->first_inner_unit(); unit;
unit= unit->next_unit())
{
JOIN *join;
for (SELECT_LEX *sl= unit->first_select_in_union(); sl;
sl= sl->next_select())
if ((join= sl->join))
join->join_free(full);
}
if (full)
{
for (tab= join_tab, end= tab+tables; tab != end; tab++)
tab->cleanup();
table= 0;
tables= 0;
}
else
{
for (tab= join_tab, end= tab+tables; tab != end; tab++)
{
if (tab->table)
tab->table->file->ha_index_or_rnd_end();
}
}
}
/*
We are not using tables anymore
Unlock all tables. We may be in an INSERT .... SELECT statement.
*/
if (full && lock && thd->lock && !(select_options & SELECT_NO_UNLOCK) &&
!select_lex->subquery_in_having)
{
// TODO: unlock tables even if the join isn't top level select in the tree
if (select_lex == (thd->lex->unit.fake_select_lex ?
thd->lex->unit.fake_select_lex : &thd->lex->select_lex))
{
mysql_unlock_read_tables(thd, lock); // Don't free join->lock
lock=0;
}
}
if (full)
{
group_fields.delete_elements();
/*
We can't call delete_elements() on copy_funcs as this will cause
problems in free_elements() as some of the elements are then deleted.
*/
tmp_table_param.copy_funcs.empty();
/*
If we have tmp_join and 'this' JOIN is not tmp_join and
tmp_table_param.copy_field's of them are equal then we have to remove
pointer to tmp_table_param.copy_field from tmp_join, because it qill
be removed in tmp_table_param.cleanup().
*/
if (tmp_join &&
tmp_join != this &&
tmp_join->tmp_table_param.copy_field ==
tmp_table_param.copy_field)
{
tmp_join->tmp_table_param.copy_field=
tmp_join->tmp_table_param.save_copy_field= 0;
}
tmp_table_param.cleanup();
}
DBUG_VOID_RETURN;
}
/*****************************************************************************
Remove the following expressions from ORDER BY and GROUP BY:
Constant expressions
Expression that only uses tables that are of type EQ_REF and the reference
is in the ORDER list or if all refereed tables are of the above type.
In the following, the X field can be removed:
SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t1.a,t2.X
SELECT * FROM t1,t2,t3 WHERE t1.a=t2.a AND t2.b=t3.b ORDER BY t1.a,t3.X
These can't be optimized:
SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t2.X,t1.a
SELECT * FROM t1,t2 WHERE t1.a=t2.a AND t1.b=t2.b ORDER BY t1.a,t2.c
SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t2.b,t1.a
*****************************************************************************/
static bool
eq_ref_table(JOIN *join, ORDER *start_order, JOIN_TAB *tab)
{
if (tab->cached_eq_ref_table) // If cached
return tab->eq_ref_table;
tab->cached_eq_ref_table=1;
if (tab->type == JT_CONST) // We can skip const tables
return (tab->eq_ref_table=1); /* purecov: inspected */
if (tab->type != JT_EQ_REF || tab->table->maybe_null)
return (tab->eq_ref_table=0); // We must use this
Item **ref_item=tab->ref.items;
Item **end=ref_item+tab->ref.key_parts;
uint found=0;
table_map map=tab->table->map;
for (; ref_item != end ; ref_item++)
{
if (! (*ref_item)->const_item())
{ // Not a const ref
ORDER *order;
for (order=start_order ; order ; order=order->next)
{
if ((*ref_item)->eq(order->item[0],0))
break;
}
if (order)
{
found++;
DBUG_ASSERT(!(order->used & map));
order->used|=map;
continue; // Used in ORDER BY
}
if (!only_eq_ref_tables(join,start_order, (*ref_item)->used_tables()))
return (tab->eq_ref_table=0);
}
}
/* Check that there was no reference to table before sort order */
for (; found && start_order ; start_order=start_order->next)
{
if (start_order->used & map)
{
found--;
continue;
}
if (start_order->depend_map & map)
return (tab->eq_ref_table=0);
}
return tab->eq_ref_table=1;
}
static bool
only_eq_ref_tables(JOIN *join,ORDER *order,table_map tables)
{
if (specialflag & SPECIAL_SAFE_MODE)
return 0; // skip this optimize /* purecov: inspected */
for (JOIN_TAB **tab=join->map2table ; tables ; tab++, tables>>=1)
{
if (tables & 1 && !eq_ref_table(join, order, *tab))
return 0;
}
return 1;
}
/* Update the dependency map for the tables */
static void update_depend_map(JOIN *join)
{
JOIN_TAB *join_tab=join->join_tab, *end=join_tab+join->tables;
for (; join_tab != end ; join_tab++)
{
TABLE_REF *ref= &join_tab->ref;
table_map depend_map=0;
Item **item=ref->items;
uint i;
for (i=0 ; i < ref->key_parts ; i++,item++)
depend_map|=(*item)->used_tables();
ref->depend_map=depend_map & ~OUTER_REF_TABLE_BIT;
depend_map&= ~OUTER_REF_TABLE_BIT;
for (JOIN_TAB **tab=join->map2table;
depend_map ;
tab++,depend_map>>=1 )
{
if (depend_map & 1)
ref->depend_map|=(*tab)->ref.depend_map;
}
}
}
/* Update the dependency map for the sort order */
static void update_depend_map(JOIN *join, ORDER *order)
{
for (; order ; order=order->next)
{
table_map depend_map;
order->item[0]->update_used_tables();
order->depend_map=depend_map=order->item[0]->used_tables();
// Not item_sum(), RAND() and no reference to table outside of sub select
if (!(order->depend_map & (OUTER_REF_TABLE_BIT | RAND_TABLE_BIT)))
{
for (JOIN_TAB **tab=join->map2table;
depend_map ;
tab++, depend_map>>=1)
{
if (depend_map & 1)
order->depend_map|=(*tab)->ref.depend_map;
}
}
}
}
/*
Remove all constants and check if ORDER only contains simple expressions
SYNOPSIS
remove_const()
join Join handler
first_order List of SORT or GROUP order
cond WHERE statement
change_list Set to 1 if we should remove things from list
If this is not set, then only simple_order is
calculated
simple_order Set to 1 if we are only using simple expressions
RETURN
Returns new sort order
simple_order is set to 1 if sort_order only uses fields from head table
and the head table is not a LEFT JOIN table
*/
static ORDER *
remove_const(JOIN *join,ORDER *first_order, COND *cond,
bool change_list, bool *simple_order)
{
if (join->tables == join->const_tables)
return change_list ? 0 : first_order; // No need to sort
ORDER *order,**prev_ptr;
table_map first_table= join->join_tab[join->const_tables].table->map;
table_map not_const_tables= ~join->const_table_map;
table_map ref;
DBUG_ENTER("remove_const");
prev_ptr= &first_order;
*simple_order= join->join_tab[join->const_tables].on_expr ? 0 : 1;
/* NOTE: A variable of not_const_tables ^ first_table; breaks gcc 2.7 */
update_depend_map(join, first_order);
for (order=first_order; order ; order=order->next)
{
table_map order_tables=order->item[0]->used_tables();
if (order->item[0]->with_sum_func)
*simple_order=0; // Must do a temp table to sort
else if (!(order_tables & not_const_tables))
{
DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
continue; // skip const item
}
else
{
if (order_tables & (RAND_TABLE_BIT | OUTER_REF_TABLE_BIT))
*simple_order=0;
else
{
Item *comp_item=0;
if (cond && const_expression_in_where(cond,order->item[0], &comp_item))
{
DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
continue;
}
if ((ref=order_tables & (not_const_tables ^ first_table)))
{
if (!(order_tables & first_table) &&
only_eq_ref_tables(join,first_order, ref))
{
DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
continue;
}
*simple_order=0; // Must do a temp table to sort
}
}
}
if (change_list)
*prev_ptr= order; // use this entry
prev_ptr= &order->next;
}
if (change_list)
*prev_ptr=0;
if (prev_ptr == &first_order) // Nothing to sort/group
*simple_order=1;
DBUG_PRINT("exit",("simple_order: %d",(int) *simple_order));
DBUG_RETURN(first_order);
}
static int
return_zero_rows(JOIN *join, select_result *result,TABLE_LIST *tables,
List<Item> &fields, bool send_row, uint select_options,
const char *info, Item *having, Procedure *procedure,
SELECT_LEX_UNIT *unit)
{
DBUG_ENTER("return_zero_rows");
if (select_options & SELECT_DESCRIBE)
{
select_describe(join, FALSE, FALSE, FALSE, info);
DBUG_RETURN(0);
}
join->join_free(0);
if (send_row)
{
for (TABLE_LIST *table=tables; table ; table=table->next)
mark_as_null_row(table->table); // All fields are NULL
if (having && having->val_int() == 0)
send_row=0;
}
if (!(result->send_fields(fields,1)))
{
if (send_row)
{
List_iterator_fast<Item> it(fields);
Item *item;
while ((item= it++))
item->no_rows_in_result();
result->send_data(fields);
}
result->send_eof(); // Should be safe
}
/* Update results for FOUND_ROWS */
join->thd->limit_found_rows= join->thd->examined_row_count= 0;
DBUG_RETURN(0);
}
/*
used only in JOIN::clear
*/
static void clear_tables(JOIN *join)
{
/*
must clear only the non-const tables, as const tables
are not re-calculated.
*/
for (uint i=join->const_tables ; i < join->tables ; i++)
mark_as_null_row(join->table[i]); // All fields are NULL
}
/*****************************************************************************
Make som simple condition optimization:
If there is a test 'field = const' change all refs to 'field' to 'const'
Remove all dummy tests 'item = item', 'const op const'.
Remove all 'item is NULL', when item can never be null!
item->marker should be 0 for all items on entry
Return in cond_value FALSE if condition is impossible (1 = 2)
*****************************************************************************/
class COND_CMP :public ilink {
public:
static void *operator new(size_t size) {return (void*) sql_alloc((uint) size); }
static void operator delete(void *ptr __attribute__((unused)),
size_t size __attribute__((unused))) {} /*lint -e715 */
Item *and_level;
Item_func *cmp_func;
COND_CMP(Item *a,Item_func *b) :and_level(a),cmp_func(b) {}
};
#ifdef __GNUC__
template class I_List<COND_CMP>;
template class I_List_iterator<COND_CMP>;
template class List<Item_func_match>;
template class List_iterator<Item_func_match>;
#endif
/*
change field = field to field = const for each found field = const in the
and_level
*/
static void
change_cond_ref_to_const(THD *thd, I_List<COND_CMP> *save_list,
Item *and_father, Item *cond,
Item *field, Item *value)
{
if (cond->type() == Item::COND_ITEM)
{
bool and_level= ((Item_cond*) cond)->functype() ==
Item_func::COND_AND_FUNC;
List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
Item *item;
while ((item=li++))
change_cond_ref_to_const(thd, save_list,and_level ? cond : item, item,
field, value);
return;
}
if (cond->eq_cmp_result() == Item::COND_OK)
return; // Not a boolean function
Item_bool_func2 *func= (Item_bool_func2*) cond;
Item **args= func->arguments();
Item *left_item= args[0];
Item *right_item= args[1];
Item_func::Functype functype= func->functype();
if (right_item->eq(field,0) && left_item != value &&
(left_item->result_type() != STRING_RESULT ||
value->result_type() != STRING_RESULT ||
left_item->collation.collation == value->collation.collation))
{
Item *tmp=value->new_item();
tmp->collation.set(right_item->collation);
if (tmp)
{
thd->change_item_tree(args + 1, tmp);
func->update_used_tables();
if ((functype == Item_func::EQ_FUNC || functype == Item_func::EQUAL_FUNC)
&& and_father != cond && !left_item->const_item())
{
cond->marker=1;
COND_CMP *tmp2;
if ((tmp2=new COND_CMP(and_father,func)))
save_list->push_back(tmp2);
}
func->set_cmp_func();
}
}
else if (left_item->eq(field,0) && right_item != value &&
(right_item->result_type() != STRING_RESULT ||
value->result_type() != STRING_RESULT ||
right_item->collation.collation == value->collation.collation))
{
Item *tmp=value->new_item();
tmp->collation.set(left_item->collation);
if (tmp)
{
thd->change_item_tree(args, tmp);
value= tmp;
func->update_used_tables();
if ((functype == Item_func::EQ_FUNC || functype == Item_func::EQUAL_FUNC)
&& and_father != cond && !right_item->const_item())
{
args[0]= args[1]; // For easy check
thd->change_item_tree(args + 1, value);
cond->marker=1;
COND_CMP *tmp2;
if ((tmp2=new COND_CMP(and_father,func)))
save_list->push_back(tmp2);
}
func->set_cmp_func();
}
}
}
/*
Remove additional condition inserted by IN/ALL/ANY transformation
SYNOPSIS
remove_additional_cond()
conds - condition for processing
RETURN VALUES
new conditions
*/
static Item *remove_additional_cond(Item* conds)
{
if (conds->name == in_additional_cond)
return 0;
if (conds->type() == Item::COND_ITEM)
{
Item_cond *cnd= (Item_cond*) conds;
List_iterator<Item> li(*(cnd->argument_list()));
Item *item;
while ((item= li++))
{
if (item->name == in_additional_cond)
{
li.remove();
if (cnd->argument_list()->elements == 1)
return cnd->argument_list()->head();
return conds;
}
}
}
return conds;
}
static void
propagate_cond_constants(THD *thd, I_List<COND_CMP> *save_list,
COND *and_father, COND *cond)
{
if (cond->type() == Item::COND_ITEM)
{
bool and_level= ((Item_cond*) cond)->functype() ==
Item_func::COND_AND_FUNC;
List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
Item *item;
I_List<COND_CMP> save;
while ((item=li++))
{
propagate_cond_constants(thd, &save,and_level ? cond : item, item);
}
if (and_level)
{ // Handle other found items
I_List_iterator<COND_CMP> cond_itr(save);
COND_CMP *cond_cmp;
while ((cond_cmp=cond_itr++))
{
Item **args= cond_cmp->cmp_func->arguments();
if (!args[0]->const_item())
change_cond_ref_to_const(thd, &save,cond_cmp->and_level,
cond_cmp->and_level, args[0], args[1]);
}
}
}
else if (and_father != cond && !cond->marker) // In a AND group
{
if (cond->type() == Item::FUNC_ITEM &&
(((Item_func*) cond)->functype() == Item_func::EQ_FUNC ||
((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC))
{
Item_func_eq *func=(Item_func_eq*) cond;
Item **args= func->arguments();
bool left_const= args[0]->const_item();
bool right_const= args[1]->const_item();
if (!(left_const && right_const) &&
args[0]->result_type() == args[1]->result_type())
{
if (right_const)
{
resolve_const_item(thd, &args[1], args[0]);
func->update_used_tables();
change_cond_ref_to_const(thd, save_list, and_father, and_father,
args[0], args[1]);
}
else if (left_const)
{
resolve_const_item(thd, &args[0], args[1]);
func->update_used_tables();
change_cond_ref_to_const(thd, save_list, and_father, and_father,
args[1], args[0]);
}
}
}
}
}
static COND *
optimize_cond(THD *thd, COND *conds, Item::cond_result *cond_value)
{
SELECT_LEX *select= thd->lex->current_select;
DBUG_ENTER("optimize_cond");
if (conds)
{
DBUG_EXECUTE("where", print_where(conds, "original"););
/* change field = field to field = const for each found field = const */
propagate_cond_constants(thd, (I_List<COND_CMP> *) 0, conds, conds);
/*
Remove all instances of item == item
Remove all and-levels where CONST item != CONST item
*/
DBUG_EXECUTE("where", print_where(conds, "after const change"););
conds= remove_eq_conds(thd, conds, cond_value);
DBUG_EXECUTE("info", print_where(conds, "after remove"););
}
else
*cond_value= Item::COND_TRUE;
DBUG_RETURN(conds);
}
/*
Remove const and eq items. Return new item, or NULL if no condition
cond_value is set to according:
COND_OK query is possible (field = constant)
COND_TRUE always true ( 1 = 1 )
COND_FALSE always false ( 1 = 2 )
*/
COND *
remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
{
if (cond->type() == Item::COND_ITEM)
{
bool and_level= ((Item_cond*) cond)->functype()
== Item_func::COND_AND_FUNC;
List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
Item::cond_result tmp_cond_value;
bool should_fix_fields=0;
*cond_value=Item::COND_UNDEF;
Item *item;
while ((item=li++))
{
Item *new_item=remove_eq_conds(thd, item, &tmp_cond_value);
if (!new_item)
li.remove();
else if (item != new_item)
{
VOID(li.replace(new_item));
should_fix_fields=1;
}
if (*cond_value == Item::COND_UNDEF)
*cond_value=tmp_cond_value;
switch (tmp_cond_value) {
case Item::COND_OK: // Not TRUE or FALSE
if (and_level || *cond_value == Item::COND_FALSE)
*cond_value=tmp_cond_value;
break;
case Item::COND_FALSE:
if (and_level)
{
*cond_value=tmp_cond_value;
return (COND*) 0; // Always false
}
break;
case Item::COND_TRUE:
if (!and_level)
{
*cond_value= tmp_cond_value;
return (COND*) 0; // Always true
}
break;
case Item::COND_UNDEF: // Impossible
break; /* purecov: deadcode */
}
}
if (should_fix_fields)
cond->update_used_tables();
if (!((Item_cond*) cond)->argument_list()->elements ||
*cond_value != Item::COND_OK)
return (COND*) 0;
if (((Item_cond*) cond)->argument_list()->elements == 1)
{ // Remove list
item= ((Item_cond*) cond)->argument_list()->head();
((Item_cond*) cond)->argument_list()->empty();
return item;
}
}
else if (cond->type() == Item::FUNC_ITEM &&
((Item_func*) cond)->functype() == Item_func::ISNULL_FUNC)
{
/*
Handles this special case for some ODBC applications:
The are requesting the row that was just updated with a auto_increment
value with this construct:
SELECT * from table_name where auto_increment_column IS NULL
This will be changed to:
SELECT * from table_name where auto_increment_column = LAST_INSERT_ID
*/
Item_func_isnull *func=(Item_func_isnull*) cond;
Item **args= func->arguments();
if (args[0]->type() == Item::FIELD_ITEM)
{
Field *field=((Item_field*) args[0])->field;
if (field->flags & AUTO_INCREMENT_FLAG && !field->table->maybe_null &&
(thd->options & OPTION_AUTO_IS_NULL) &&
thd->current_insert_id && thd->substitute_null_with_insert_id)
{
#ifdef HAVE_QUERY_CACHE
query_cache_abort(&thd->net);
#endif
COND *new_cond;
if ((new_cond= new Item_func_eq(args[0],
new Item_int("last_insert_id()",
thd->current_insert_id,
21))))
{
/*
Set THD::last_insert_id_used manually, as this statement
uses LAST_INSERT_ID() in a sense, and should issue
LAST_INSERT_ID_EVENT.
*/
thd->last_insert_id_used= TRUE;
cond=new_cond;
cond->fix_fields(thd, 0, &cond);
}
thd->substitute_null_with_insert_id= FALSE; // Clear for next request
}
/* fix to replace 'NULL' dates with '0' (shreeve@uci.edu) */
else if (((field->type() == FIELD_TYPE_DATE) ||
(field->type() == FIELD_TYPE_DATETIME)) &&
(field->flags & NOT_NULL_FLAG) &&
!field->table->maybe_null)
{
COND *new_cond;
if ((new_cond= new Item_func_eq(args[0],new Item_int("0", 0, 2))))
{
cond=new_cond;
cond->fix_fields(thd, 0, &cond);
}
}
}
}
else if (cond->const_item())
{
*cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
return (COND*) 0;
}
else if ((*cond_value= cond->eq_cmp_result()) != Item::COND_OK)
{ // boolan compare function
Item *left_item= ((Item_func*) cond)->arguments()[0];
Item *right_item= ((Item_func*) cond)->arguments()[1];
if (left_item->eq(right_item,1))
{
if (!left_item->maybe_null ||
((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC)
return (COND*) 0; // Compare of identical items
}
}
*cond_value=Item::COND_OK;
return cond; // Point at next and level
}
/*
Return 1 if the item is a const value in all the WHERE clause
*/
static bool
const_expression_in_where(COND *cond, Item *comp_item, Item **const_item)
{
if (cond->type() == Item::COND_ITEM)
{
bool and_level= (((Item_cond*) cond)->functype()
== Item_func::COND_AND_FUNC);
List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
Item *item;
while ((item=li++))
{
bool res=const_expression_in_where(item, comp_item, const_item);
if (res) // Is a const value
{
if (and_level)
return 1;
}
else if (!and_level)
return 0;
}
return and_level ? 0 : 1;
}
else if (cond->eq_cmp_result() != Item::COND_OK)
{ // boolan compare function
Item_func* func= (Item_func*) cond;
if (func->functype() != Item_func::EQUAL_FUNC &&
func->functype() != Item_func::EQ_FUNC)
return 0;
Item *left_item= ((Item_func*) cond)->arguments()[0];
Item *right_item= ((Item_func*) cond)->arguments()[1];
if (left_item->eq(comp_item,1))
{
if (right_item->const_item())
{
if (*const_item)
return right_item->eq(*const_item, 1);
*const_item=right_item;
return 1;
}
}
else if (right_item->eq(comp_item,1))
{
if (left_item->const_item())
{
if (*const_item)
return left_item->eq(*const_item, 1);
*const_item=left_item;
return 1;
}
}
}
return 0;
}
/****************************************************************************
Create internal temporary table
****************************************************************************/
/*
Create field for temporary table from given field
SYNOPSIS
create_tmp_field_from_field()
thd Thread handler
org_field field from which new field will be created
name New field name
item Item to create a field for
table Temporary table
item !=NULL if item->result_field should point to new field.
This is relevant for how fill_record() is going to work:
If item != NULL then fill_record() will update
the record in the original table.
If item == NULL then fill_record() will update
the temporary table
convert_blob_length If >0 create a varstring(convert_blob_length) field
instead of blob.
RETURN
0 on error
new_created field
*/
static Field* create_tmp_field_from_field(THD *thd, Field* org_field,
const char *name, TABLE *table,
Item_field *item,
uint convert_blob_length)
{
Field *new_field;
if (convert_blob_length && org_field->flags & BLOB_FLAG)
new_field= new Field_varstring(convert_blob_length, org_field->maybe_null(),
org_field->field_name, table,
org_field->charset());
else
new_field= org_field->new_field(thd->mem_root, table);
if (new_field)
{
if (item)
item->result_field= new_field;
else
new_field->field_name= name;
if (org_field->maybe_null() || (item && item->maybe_null))
new_field->flags&= ~NOT_NULL_FLAG; // Because of outer join
if (org_field->type() == FIELD_TYPE_VAR_STRING)
table->db_create_options|= HA_OPTION_PACK_RECORD;
}
return new_field;
}
/*
Create field for temporary table using type of given item
SYNOPSIS
create_tmp_field_from_item()
thd Thread handler
item Item to create a field for
table Temporary table
copy_func If set and item is a function, store copy of item
in this array
modify_item 1 if item->result_field should point to new item.
This is relevent for how fill_record() is going to
work:
If modify_item is 1 then fill_record() will update
the record in the original table.
If modify_item is 0 then fill_record() will update
the temporary table
convert_blob_length If >0 create a varstring(convert_blob_length) field
instead of blob.
RETURN
0 on error
new_created field
*/
static Field* create_tmp_field_from_item(THD *thd, Item *item, TABLE *table,
Item ***copy_func, bool modify_item,
uint convert_blob_length)
{
bool maybe_null=item->maybe_null;
Field *new_field;
LINT_INIT(new_field);
switch (item->result_type()) {
case REAL_RESULT:
new_field=new Field_double(item->max_length, maybe_null,
item->name, table, item->decimals);
break;
case INT_RESULT:
new_field=new Field_longlong(item->max_length, maybe_null,
item->name, table, item->unsigned_flag);
break;
case STRING_RESULT:
DBUG_ASSERT(item->collation.collation);
enum enum_field_types type;
/*
DATE/TIME fields have STRING_RESULT result type. To preserve
type they needed to be handled separately.
*/
if ((type= item->field_type()) == MYSQL_TYPE_DATETIME ||
type == MYSQL_TYPE_TIME || type == MYSQL_TYPE_DATE)
new_field= item->tmp_table_field_from_field_type(table);
else if (item->max_length/item->collation.collation->mbmaxlen >
CONVERT_IF_BIGGER_TO_BLOB)
{
if (convert_blob_length)
new_field= new Field_varstring(convert_blob_length, maybe_null,
item->name, table,
item->collation.collation);
else
new_field= new Field_blob(item->max_length, maybe_null, item->name,
table, item->collation.collation);
}
else
new_field= new Field_string(item->max_length, maybe_null, item->name,
table, item->collation.collation);
break;
case ROW_RESULT:
default:
// This case should never be choosen
DBUG_ASSERT(0);
new_field= 0; // to satisfy compiler (uninitialized variable)
break;
}
if (copy_func && item->is_result_field())
*((*copy_func)++) = item; // Save for copy_funcs
if (modify_item)
item->set_result_field(new_field);
return new_field;
}
/*
Create field for temporary table
SYNOPSIS
create_tmp_field()
thd Thread handler
table Temporary table
item Item to create a field for
type Type of item (normally item->type)
copy_func If set and item is a function, store copy of item
in this array
from_field if field will be created using other field as example,
pointer example field will be written here
group 1 if we are going to do a relative group by on result
modify_item 1 if item->result_field should point to new item.
This is relevent for how fill_record() is going to
work:
If modify_item is 1 then fill_record() will update
the record in the original table.
If modify_item is 0 then fill_record() will update
the temporary table
convert_blob_length If >0 create a varstring(convert_blob_length) field
instead of blob.
RETURN
0 on error
new_created field
*/
Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
Item ***copy_func, Field **from_field,
bool group, bool modify_item, uint convert_blob_length,
bool make_copy_field)
{
switch (type) {
case Item::SUM_FUNC_ITEM:
{
Item_sum *item_sum=(Item_sum*) item;
bool maybe_null=item_sum->maybe_null;
switch (item_sum->sum_func()) {
case Item_sum::AVG_FUNC: /* Place for sum & count */
if (group)
return new Field_string(sizeof(double)+sizeof(longlong),
0, item->name,table,&my_charset_bin);
else
return new Field_double(item_sum->max_length,maybe_null,
item->name, table, item_sum->decimals);
case Item_sum::VARIANCE_FUNC: /* Place for sum & count */
case Item_sum::STD_FUNC:
if (group)
return new Field_string(sizeof(double)*2+sizeof(longlong),
0, item->name,table,&my_charset_bin);
else
return new Field_double(item_sum->max_length, maybe_null,
item->name,table,item_sum->decimals);
case Item_sum::UNIQUE_USERS_FUNC:
return new Field_long(9,maybe_null,item->name,table,1);
case Item_sum::MIN_FUNC:
case Item_sum::MAX_FUNC:
if (item_sum->args[0]->type() == Item::FIELD_ITEM)
{
*from_field= ((Item_field*) item_sum->args[0])->field;
return create_tmp_field_from_field(thd, *from_field, item->name, table,
NULL, convert_blob_length);
}
/* fall through */
default:
switch (item_sum->result_type()) {
case REAL_RESULT:
return new Field_double(item_sum->max_length,maybe_null,
item->name,table,item_sum->decimals);
case INT_RESULT:
return new Field_longlong(item_sum->max_length,maybe_null,
item->name,table,item->unsigned_flag);
case STRING_RESULT:
if (item_sum->max_length/item_sum->collation.collation->mbmaxlen >
CONVERT_IF_BIGGER_TO_BLOB)
{
if (convert_blob_length)
return new Field_varstring(convert_blob_length, maybe_null,
item->name, table,
item->collation.collation);
else
return new Field_blob(item_sum->max_length, maybe_null, item->name,
table, item->collation.collation);
}
return new Field_string(item_sum->max_length,maybe_null,
item->name,table,item->collation.collation);
case ROW_RESULT:
default:
// This case should never be choosen
DBUG_ASSERT(0);
thd->fatal_error();
return 0;
}
}
/* We never come here */
}
case Item::FIELD_ITEM:
case Item::DEFAULT_VALUE_ITEM:
{
Item_field *field= (Item_field*) item;
return create_tmp_field_from_field(thd, (*from_field= field->field),
item->name, table,
modify_item ? (Item_field*) item : NULL,
convert_blob_length);
}
case Item::FUNC_ITEM:
case Item::COND_ITEM:
case Item::FIELD_AVG_ITEM:
case Item::FIELD_STD_ITEM:
case Item::SUBSELECT_ITEM:
/* The following can only happen with 'CREATE TABLE ... SELECT' */
case Item::PROC_ITEM:
case Item::INT_ITEM:
case Item::REAL_ITEM:
case Item::STRING_ITEM:
case Item::REF_ITEM:
case Item::NULL_ITEM:
case Item::VARBIN_ITEM:
if (make_copy_field)
{
DBUG_ASSERT(((Item_result_field*)item)->result_field);
*from_field= ((Item_result_field*)item)->result_field;
}
return create_tmp_field_from_item(thd, item, table, (make_copy_field ? 0 :
copy_func), modify_item,
convert_blob_length);
case Item::TYPE_HOLDER:
return ((Item_type_holder *)item)->make_field_by_type(table);
default: // Dosen't have to be stored
return 0;
}
}
/*
Create a temp table according to a field list.
Set distinct if duplicates could be removed
Given fields field pointers are changed to point at tmp_table
for send_fields
*/
TABLE *
create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
ORDER *group, bool distinct, bool save_sum_fields,
ulong select_options, ha_rows rows_limit,
char *table_alias)
{
TABLE *table;
uint i,field_count,reclength,null_count,null_pack_length,
hidden_null_count, hidden_null_pack_length, hidden_field_count,
blob_count,group_null_items;
bool using_unique_constraint=0;
bool not_all_columns= !(select_options & TMP_TABLE_ALL_COLUMNS);
char *tmpname,path[FN_REFLEN];
byte *pos,*group_buff;
uchar *null_flags;
Field **reg_field, **from_field, **blob_field;
Copy_field *copy=0;
KEY *keyinfo;
KEY_PART_INFO *key_part_info;
Item **copy_func;
MI_COLUMNDEF *recinfo;
uint temp_pool_slot=MY_BIT_NONE;
bool force_copy_fields= param->force_copy_fields;
DBUG_ENTER("create_tmp_table");
DBUG_PRINT("enter",("distinct: %d save_sum_fields: %d rows_limit: %lu group: %d",
(int) distinct, (int) save_sum_fields,
(ulong) rows_limit,test(group)));
statistic_increment(created_tmp_tables, &LOCK_status);
if (use_temp_pool)
temp_pool_slot = bitmap_set_next(&temp_pool);
if (temp_pool_slot != MY_BIT_NONE) // we got a slot
sprintf(path, "%s_%lx_%i", tmp_file_prefix,
current_pid, temp_pool_slot);
else // if we run out of slots or we are not using tempool
sprintf(path,"%s%lx_%lx_%x", tmp_file_prefix,current_pid,
thd->thread_id, thd->tmp_table++);
fn_format(path, path, mysql_tmpdir, "", MY_REPLACE_EXT|MY_UNPACK_FILENAME);
if (lower_case_table_names)
my_casedn_str(files_charset_info, path);
if (group)
{
if (!param->quick_group)
group=0; // Can't use group key
else for (ORDER *tmp=group ; tmp ; tmp=tmp->next)
{
(*tmp->item)->marker=4; // Store null in key
if ((*tmp->item)->max_length >= MAX_CHAR_WIDTH)
using_unique_constraint=1;
}
if (param->group_length >= MAX_BLOB_WIDTH)
using_unique_constraint=1;
if (group)
distinct=0; // Can't use distinct
}
field_count=param->field_count+param->func_count+param->sum_func_count;
hidden_field_count=param->hidden_field_count;
if (!my_multi_malloc(MYF(MY_WME),
&table,sizeof(*table),
&reg_field, sizeof(Field*)*(field_count+1),
&blob_field, sizeof(Field*)*(field_count+1),
&from_field, sizeof(Field*)*field_count,
&copy_func,sizeof(*copy_func)*(param->func_count+1),
&param->keyinfo,sizeof(*param->keyinfo),
&key_part_info,
sizeof(*key_part_info)*(param->group_parts+1),
&param->start_recinfo,
sizeof(*param->recinfo)*(field_count*2+4),
&tmpname,(uint) strlen(path)+1,
&group_buff,group && ! using_unique_constraint ?
param->group_length : 0,
NullS))
{
if (temp_pool_slot != MY_BIT_NONE)
bitmap_clear_bit(&temp_pool, temp_pool_slot);
DBUG_RETURN(NULL); /* purecov: inspected */
}
if (!(param->copy_field=copy=new Copy_field[field_count]))
{
if (temp_pool_slot != MY_BIT_NONE)
bitmap_clear_bit(&temp_pool, temp_pool_slot);
my_free((gptr) table,MYF(0)); /* purecov: inspected */
DBUG_RETURN(NULL); /* purecov: inspected */
}
param->items_to_copy= copy_func;
strmov(tmpname,path);
/* make table according to fields */
bzero((char*) table,sizeof(*table));
bzero((char*) reg_field,sizeof(Field*)*(field_count+1));
bzero((char*) from_field,sizeof(Field*)*field_count);
table->field=reg_field;
table->blob_field= (Field_blob**) blob_field;
table->real_name=table->path=tmpname;
table->table_name= table_alias;
table->reginfo.lock_type=TL_WRITE; /* Will be updated */
table->db_stat=HA_OPEN_KEYFILE+HA_OPEN_RNDFILE;
table->blob_ptr_size=mi_portable_sizeof_char_ptr;
table->map=1;
table->tmp_table= TMP_TABLE;
table->db_low_byte_first=1; // True for HEAP and MyISAM
table->temp_pool_slot = temp_pool_slot;
table->copy_blobs= 1;
table->in_use= thd;
table->keys_for_keyread.init();
table->keys_in_use.init();
table->read_only_keys.init();
table->quick_keys.init();
table->used_keys.init();
table->keys_in_use_for_query.init();
/* Calculate which type of fields we will store in the temporary table */
reclength=blob_count=null_count=hidden_null_count=group_null_items=0;
param->using_indirect_summary_function=0;
List_iterator_fast<Item> li(fields);
Item *item;
Field **tmp_from_field=from_field;
while ((item=li++))
{
Item::Type type=item->type();
if (not_all_columns)
{
if (item->with_sum_func && type != Item::SUM_FUNC_ITEM)
{
/*
Mark that the we have ignored an item that refers to a summary
function. We need to know this if someone is going to use
DISTINCT on the result.
*/
param->using_indirect_summary_function=1;
continue;
}
if (item->const_item() && (int) hidden_field_count <= 0)
continue; // We don't have to store this
}
if (type == Item::SUM_FUNC_ITEM && !group && !save_sum_fields)
{ /* Can't calc group yet */
((Item_sum*) item)->result_field=0;
for (i=0 ; i < ((Item_sum*) item)->arg_count ; i++)
{
Item **argp= ((Item_sum*) item)->args + i;
Item *arg= *argp;
if (!arg->const_item())
{
Field *new_field=
create_tmp_field(thd, table, arg, arg->type(), &copy_func,
tmp_from_field, group != 0,not_all_columns,
param->convert_blob_length, 0);
if (!new_field)
goto err; // Should be OOM
tmp_from_field++;
*(reg_field++)= new_field;
reclength+=new_field->pack_length();
if (new_field->flags & BLOB_FLAG)
{
*blob_field++= new_field;
blob_count++;
}
thd->change_item_tree(argp, new Item_field(new_field));
if (!(new_field->flags & NOT_NULL_FLAG))
{
null_count++;
/*
new_field->maybe_null() is still false, it will be
changed below. But we have to setup Item_field correctly
*/
(*argp)->maybe_null=1;
}
}
}
}
else
{
/*
The last parameter to create_tmp_field() is a bit tricky:
We need to set it to 0 in union, to get fill_record() to modify the
temporary table.
We need to set it to 1 on multi-table-update and in select to
write rows to the temporary table.
We here distinguish between UNION and multi-table-updates by the fact
that in the later case group is set to the row pointer.
*/
Field *new_field= create_tmp_field(thd, table, item, type, &copy_func,
tmp_from_field, group != 0,
!force_copy_fields &&
(not_all_columns || group !=0),
param->convert_blob_length,
force_copy_fields);
if (!new_field)
{
if (thd->is_fatal_error)
goto err; // Got OOM
continue; // Some kindf of const item
}
if (type == Item::SUM_FUNC_ITEM)
((Item_sum *) item)->result_field= new_field;
tmp_from_field++;
reclength+=new_field->pack_length();
if (!(new_field->flags & NOT_NULL_FLAG))
null_count++;
if (new_field->flags & BLOB_FLAG)
{
*blob_field++= new_field;
blob_count++;
}
if (item->marker == 4 && item->maybe_null)
{
group_null_items++;
new_field->flags|= GROUP_FLAG;
}
*(reg_field++) =new_field;
}
if (!--hidden_field_count)
{
hidden_null_count=null_count;
/*
We need to update hidden_field_count as we may have stored group
functions with constant arguments
*/
param->hidden_field_count= (uint) (reg_field - table->field);
}
}
DBUG_ASSERT(field_count >= (uint) (reg_field - table->field));
field_count= (uint) (reg_field - table->field);
*blob_field= 0; // End marker
/* If result table is small; use a heap */
if (blob_count || using_unique_constraint ||
(select_options & (OPTION_BIG_TABLES | SELECT_SMALL_RESULT)) ==
OPTION_BIG_TABLES ||(select_options & TMP_TABLE_FORCE_MYISAM))
{
table->file=get_new_handler(table,table->db_type=DB_TYPE_MYISAM);
if (group &&
(param->group_parts > table->file->max_key_parts() ||
param->group_length > table->file->max_key_length()))
using_unique_constraint=1;
}
else
{
table->file=get_new_handler(table,table->db_type=DB_TYPE_HEAP);
}
if (!using_unique_constraint)
reclength+= group_null_items; // null flag is stored separately
table->blob_fields=blob_count;
if (blob_count == 0)
{
/* We need to ensure that first byte is not 0 for the delete link */
if (param->hidden_field_count)
hidden_null_count++;
else
null_count++;
}
hidden_null_pack_length=(hidden_null_count+7)/8;
null_pack_length=hidden_null_count+(null_count+7)/8;
reclength+=null_pack_length;
if (!reclength)
reclength=1; // Dummy select
table->fields=field_count;
table->reclength=reclength;
{
uint alloc_length=ALIGN_SIZE(reclength+MI_UNIQUE_HASH_LENGTH+1);
table->rec_buff_length=alloc_length;
if (!(table->record[0]= (byte *) my_malloc(alloc_length*3, MYF(MY_WME))))
goto err;
table->record[1]= table->record[0]+alloc_length;
table->default_values= table->record[1]+alloc_length;
}
copy_func[0]=0; // End marker
recinfo=param->start_recinfo;
null_flags=(uchar*) table->record[0];
pos=table->record[0]+ null_pack_length;
if (null_pack_length)
{
bzero((byte*) recinfo,sizeof(*recinfo));
recinfo->type=FIELD_NORMAL;
recinfo->length=null_pack_length;
recinfo++;
bfill(null_flags,null_pack_length,255); // Set null fields
table->null_flags= (uchar*) table->record[0];
table->null_fields= null_count+ hidden_null_count;
table->null_bytes= null_pack_length;
}
null_count= (blob_count == 0) ? 1 : 0;
hidden_field_count=param->hidden_field_count;
for (i=0,reg_field=table->field; i < field_count; i++,reg_field++,recinfo++)
{
Field *field= *reg_field;
uint length;
bzero((byte*) recinfo,sizeof(*recinfo));
if (!(field->flags & NOT_NULL_FLAG))
{
if (field->flags & GROUP_FLAG && !using_unique_constraint)
{
/*
We have to reserve one byte here for NULL bits,
as this is updated by 'end_update()'
*/
*pos++=0; // Null is stored here
recinfo->length=1;
recinfo->type=FIELD_NORMAL;
recinfo++;
bzero((byte*) recinfo,sizeof(*recinfo));
}
else
{
recinfo->null_bit= 1 << (null_count & 7);
recinfo->null_pos= null_count/8;
}
field->move_field((char*) pos,null_flags+null_count/8,
1 << (null_count & 7));
null_count++;
}
else
field->move_field((char*) pos,(uchar*) 0,0);
field->reset();
if (from_field[i])
{ /* Not a table Item */
copy->set(field,from_field[i],save_sum_fields);
copy++;
}
length=field->pack_length();
pos+= length;
/* Make entry for create table */
recinfo->length=length;
if (field->flags & BLOB_FLAG)
recinfo->type= (int) FIELD_BLOB;
else if (!field->zero_pack() &&
(field->type() == FIELD_TYPE_STRING ||
field->type() == FIELD_TYPE_VAR_STRING) &&
length >= 10 && blob_count)
recinfo->type=FIELD_SKIP_ENDSPACE;
else
recinfo->type=FIELD_NORMAL;
if (!--hidden_field_count)
null_count=(null_count+7) & ~7; // move to next byte
// fix table name in field entry
field->table_name= table->table_name;
}
param->copy_field_end=copy;
param->recinfo=recinfo;
store_record(table,default_values); // Make empty default record
if (thd->variables.tmp_table_size == ~(ulong) 0) // No limit
table->max_rows= ~(ha_rows) 0;
else
table->max_rows=(((table->db_type == DB_TYPE_HEAP) ?
min(thd->variables.tmp_table_size,
thd->variables.max_heap_table_size) :
thd->variables.tmp_table_size)/ table->reclength);
set_if_bigger(table->max_rows,1); // For dummy start options
/*
Push the LIMIT clause to the temporary table creation, so that we
materialize only up to 'rows_limit' records instead of all result records.
*/
set_if_smaller(table->max_rows, rows_limit);
param->end_write_records= rows_limit;
keyinfo=param->keyinfo;
if (group)
{
DBUG_PRINT("info",("Creating group key in temporary table"));
table->group=group; /* Table is grouped by key */
param->group_buff=group_buff;
table->keys=1;
table->uniques= test(using_unique_constraint);
table->key_info=keyinfo;
keyinfo->key_part=key_part_info;
keyinfo->flags=HA_NOSAME;
keyinfo->usable_key_parts=keyinfo->key_parts= param->group_parts;
keyinfo->key_length=0;
keyinfo->rec_per_key=0;
keyinfo->algorithm= HA_KEY_ALG_UNDEF;
ORDER *cur_group= group;
for (; cur_group ; cur_group= cur_group->next, key_part_info++)
{
Field *field=(*cur_group->item)->get_tmp_table_field();
bool maybe_null=(*cur_group->item)->maybe_null;
key_part_info->null_bit=0;
key_part_info->field= field;
key_part_info->offset= field->offset();
key_part_info->length= (uint16) field->pack_length();
key_part_info->type= (uint8) field->key_type();
key_part_info->key_type =
((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
(ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT) ?
0 : FIELDFLAG_BINARY;
if (!using_unique_constraint)
{
cur_group->buff=(char*) group_buff;
if (!(cur_group->field=field->new_field(thd->mem_root,table)))
goto err; /* purecov: inspected */
if (maybe_null)
{
/*
To be able to group on NULL, we reserve place in group_buff
for the NULL flag just before the column.
The field data is after this flag.
The NULL flag is updated by 'end_update()' and 'end_write()'
*/
keyinfo->flags|= HA_NULL_ARE_EQUAL; // def. that NULL == NULL
key_part_info->null_bit=field->null_bit;
key_part_info->null_offset= (uint) (field->null_ptr -
(uchar*) table->record[0]);
cur_group->field->move_field((char*) ++cur_group->buff);
group_buff++;
}
else
cur_group->field->move_field((char*) group_buff);
group_buff+= key_part_info->length;
}
keyinfo->key_length+= key_part_info->length;
}
}
if (distinct && field_count != param->hidden_field_count)
{
/*
Create an unique key or an unique constraint over all columns
that should be in the result. In the temporary table, there are
'param->hidden_field_count' extra columns, whose null bits are stored
in the first 'hidden_null_pack_length' bytes of the row.
*/
DBUG_PRINT("info",("hidden_field_count: %d", param->hidden_field_count));
null_pack_length-=hidden_null_pack_length;
keyinfo->key_parts= ((field_count-param->hidden_field_count)+
test(null_pack_length));
table->distinct=1;
table->keys=1;
if (blob_count)
{
using_unique_constraint=1;
table->uniques=1;
}
if (!(key_part_info= (KEY_PART_INFO*)
sql_calloc((keyinfo->key_parts)*sizeof(KEY_PART_INFO))))
goto err;
table->key_info=keyinfo;
keyinfo->key_part=key_part_info;
keyinfo->flags=HA_NOSAME | HA_NULL_ARE_EQUAL;
keyinfo->key_length=(uint16) reclength;
keyinfo->name=(char*) "tmp";
keyinfo->algorithm= HA_KEY_ALG_UNDEF;
keyinfo->rec_per_key=0;
if (null_pack_length)
{
key_part_info->null_bit=0;
key_part_info->offset=hidden_null_pack_length;
key_part_info->length=null_pack_length;
key_part_info->field=new Field_string((char*) table->record[0],
(uint32) key_part_info->length,
(uchar*) 0,
(uint) 0,
Field::NONE,
NullS, table, &my_charset_bin);
key_part_info->key_type=FIELDFLAG_BINARY;
key_part_info->type= HA_KEYTYPE_BINARY;
key_part_info++;
}
/* Create a distinct key over the columns we are going to return */
for (i=param->hidden_field_count, reg_field=table->field + i ;
i < field_count;
i++, reg_field++, key_part_info++)
{
key_part_info->null_bit=0;
key_part_info->field= *reg_field;
key_part_info->offset= (*reg_field)->offset();
key_part_info->length= (uint16) (*reg_field)->pack_length();
key_part_info->type= (uint8) (*reg_field)->key_type();
key_part_info->key_type =
((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
(ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT) ?
0 : FIELDFLAG_BINARY;
}
}
if (thd->is_fatal_error) // If end of memory
goto err; /* purecov: inspected */
table->db_record_offset=1;
if (table->db_type == DB_TYPE_MYISAM)
{
if (create_myisam_tmp_table(table,param,select_options))
goto err;
}
if (!open_tmp_table(table))
DBUG_RETURN(table);
err:
/*
Hack to ensure that free_blobs() doesn't fail if blob_field is not yet
complete
*/
*table->blob_field= 0;
free_tmp_table(thd,table); /* purecov: inspected */
if (temp_pool_slot != MY_BIT_NONE)
bitmap_clear_bit(&temp_pool, temp_pool_slot);
DBUG_RETURN(NULL); /* purecov: inspected */
}
static bool open_tmp_table(TABLE *table)
{
int error;
if ((error=table->file->ha_open(table->real_name,O_RDWR,HA_OPEN_TMP_TABLE)))
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
table->db_stat=0;
return(1);
}
(void) table->file->extra(HA_EXTRA_QUICK); /* Faster */
return(0);
}
static bool create_myisam_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
ulong options)
{
int error;
MI_KEYDEF keydef;
MI_UNIQUEDEF uniquedef;
KEY *keyinfo=param->keyinfo;
DBUG_ENTER("create_myisam_tmp_table");
if (table->keys)
{ // Get keys for ni_create
bool using_unique_constraint=0;
HA_KEYSEG *seg= (HA_KEYSEG*) sql_calloc(sizeof(*seg) *
keyinfo->key_parts);
if (!seg)
goto err;
if (keyinfo->key_length >= table->file->max_key_length() ||
keyinfo->key_parts > table->file->max_key_parts() ||
table->uniques)
{
/* Can't create a key; Make a unique constraint instead of a key */
table->keys=0;
table->uniques=1;
using_unique_constraint=1;
bzero((char*) &uniquedef,sizeof(uniquedef));
uniquedef.keysegs=keyinfo->key_parts;
uniquedef.seg=seg;
uniquedef.null_are_equal=1;
/* Create extra column for hash value */
bzero((byte*) param->recinfo,sizeof(*param->recinfo));
param->recinfo->type= FIELD_CHECK;
param->recinfo->length=MI_UNIQUE_HASH_LENGTH;
param->recinfo++;
table->reclength+=MI_UNIQUE_HASH_LENGTH;
}
else
{
/* Create an unique key */
bzero((char*) &keydef,sizeof(keydef));
keydef.flag=HA_NOSAME | HA_BINARY_PACK_KEY | HA_PACK_KEY;
keydef.keysegs= keyinfo->key_parts;
keydef.seg= seg;
}
for (uint i=0; i < keyinfo->key_parts ; i++,seg++)
{
Field *field=keyinfo->key_part[i].field;
seg->flag= 0;
seg->language= field->charset()->number;
seg->length= keyinfo->key_part[i].length;
seg->start= keyinfo->key_part[i].offset;
if (field->flags & BLOB_FLAG)
{
seg->type=
((keyinfo->key_part[i].key_type & FIELDFLAG_BINARY) ?
HA_KEYTYPE_VARBINARY : HA_KEYTYPE_VARTEXT);
seg->bit_start=seg->length - table->blob_ptr_size;
seg->flag= HA_BLOB_PART;
seg->length=0; // Whole blob in unique constraint
}
else
{
seg->type=
((keyinfo->key_part[i].key_type & FIELDFLAG_BINARY) ?
HA_KEYTYPE_BINARY : HA_KEYTYPE_TEXT);
if (!(field->flags & ZEROFILL_FLAG) &&
(field->type() == FIELD_TYPE_STRING ||
field->type() == FIELD_TYPE_VAR_STRING) &&
keyinfo->key_part[i].length > 4)
seg->flag|=HA_SPACE_PACK;
}
if (!(field->flags & NOT_NULL_FLAG))
{
seg->null_bit= field->null_bit;
seg->null_pos= (uint) (field->null_ptr - (uchar*) table->record[0]);
/*
We are using a GROUP BY on something that contains NULL
In this case we have to tell MyISAM that two NULL should
on INSERT be compared as equal
*/
if (!using_unique_constraint)
keydef.flag|= HA_NULL_ARE_EQUAL;
}
}
}
MI_CREATE_INFO create_info;
bzero((char*) &create_info,sizeof(create_info));
if ((options & (OPTION_BIG_TABLES | SELECT_SMALL_RESULT)) ==
OPTION_BIG_TABLES)
create_info.data_file_length= ~(ulonglong) 0;
if ((error=mi_create(table->real_name,table->keys,&keydef,
(uint) (param->recinfo-param->start_recinfo),
param->start_recinfo,
table->uniques, &uniquedef,
&create_info,
HA_CREATE_TMP_TABLE)))
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
table->db_stat=0;
goto err;
}
statistic_increment(created_tmp_disk_tables, &LOCK_status);
table->db_record_offset=1;
DBUG_RETURN(0);
err:
DBUG_RETURN(1);
}
void
free_tmp_table(THD *thd, TABLE *entry)
{
const char *save_proc_info;
DBUG_ENTER("free_tmp_table");
DBUG_PRINT("enter",("table: %s",entry->table_name));
save_proc_info=thd->proc_info;
thd->proc_info="removing tmp table";
free_blobs(entry);
if (entry->file)
{
if (entry->db_stat)
{
(void) entry->file->close();
}
/*
We can't call ha_delete_table here as the table may created in mixed case
here and we have to ensure that delete_table gets the table name in
the original case.
*/
if (!(test_flags & TEST_KEEP_TMP_TABLES) || entry->db_type == DB_TYPE_HEAP)
entry->file->delete_table(entry->real_name);
delete entry->file;
}
/* free blobs */
for (Field **ptr=entry->field ; *ptr ; ptr++)
(*ptr)->free();
my_free((gptr) entry->record[0],MYF(0));
free_io_cache(entry);
if (entry->temp_pool_slot != MY_BIT_NONE)
bitmap_clear_bit(&temp_pool, entry->temp_pool_slot);
my_free((gptr) entry,MYF(0));
thd->proc_info=save_proc_info;
DBUG_VOID_RETURN;
}
/*
* If a HEAP table gets full, create a MyISAM table and copy all rows to this
*/
bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
int error, bool ignore_last_dupp_key_error)
{
TABLE new_table;
const char *save_proc_info;
int write_err;
DBUG_ENTER("create_myisam_from_heap");
if (table->db_type != DB_TYPE_HEAP || error != HA_ERR_RECORD_FILE_FULL)
{
table->file->print_error(error,MYF(0));
DBUG_RETURN(1);
}
new_table= *table;
new_table.db_type=DB_TYPE_MYISAM;
if (!(new_table.file=get_new_handler(&new_table,DB_TYPE_MYISAM)))
DBUG_RETURN(1); // End of memory
save_proc_info=thd->proc_info;
thd->proc_info="converting HEAP to MyISAM";
if (create_myisam_tmp_table(&new_table,param,
thd->lex->select_lex.options | thd->options))
goto err2;
if (open_tmp_table(&new_table))
goto err1;
if (table->file->indexes_are_disabled())
new_table.file->disable_indexes(HA_KEY_SWITCH_ALL);
table->file->ha_index_or_rnd_end();
table->file->ha_rnd_init(1);
if (table->no_rows)
{
new_table.file->extra(HA_EXTRA_NO_ROWS);
new_table.no_rows=1;
}
#ifdef TO_BE_DONE_LATER_IN_4_1
/*
To use start_bulk_insert() (which is new in 4.1) we need to find
all places where a corresponding end_bulk_insert() should be put.
*/
table->file->info(HA_STATUS_VARIABLE); /* update table->file->records */
new_table.file->start_bulk_insert(table->file->records);
#else
/* HA_EXTRA_WRITE_CACHE can stay until close, no need to disable it */
new_table.file->extra(HA_EXTRA_WRITE_CACHE);
#endif
/* copy all old rows */
while (!table->file->rnd_next(new_table.record[1]))
{
if ((write_err=new_table.file->write_row(new_table.record[1])))
goto err;
}
/* copy row that filled HEAP table */
if ((write_err=new_table.file->write_row(table->record[0])))
{
if (write_err != HA_ERR_FOUND_DUPP_KEY &&
write_err != HA_ERR_FOUND_DUPP_UNIQUE || !ignore_last_dupp_key_error)
goto err;
}
/* remove heap table and change to use myisam table */
(void) table->file->ha_rnd_end();
(void) table->file->close();
(void) table->file->delete_table(table->real_name);
delete table->file;
table->file=0;
*table =new_table;
table->file->change_table_ptr(table);
thd->proc_info= (!strcmp(save_proc_info,"Copying to tmp table") ?
"Copying to tmp table on disk" : save_proc_info);
DBUG_RETURN(0);
err:
DBUG_PRINT("error",("Got error: %d",write_err));
table->file->print_error(error,MYF(0)); // Give table is full error
(void) table->file->ha_rnd_end();
(void) new_table.file->close();
err1:
new_table.file->delete_table(new_table.real_name);
delete new_table.file;
err2:
thd->proc_info=save_proc_info;
DBUG_RETURN(1);
}
/****************************************************************************
Make a join of all tables and write it on socket or to table
Return: 0 if ok
1 if error is sent
-1 if error should be sent
****************************************************************************/
static int
do_select(JOIN *join,List<Item> *fields,TABLE *table,Procedure *procedure)
{
int error= 0;
JOIN_TAB *join_tab;
int (*end_select)(JOIN *, struct st_join_table *,bool);
DBUG_ENTER("do_select");
List<Item> *columns_list= procedure ? &join->procedure_fields_list : fields;
join->procedure=procedure;
/*
Tell the client how many fields there are in a row
*/
if (!table)
join->result->send_fields(*columns_list, 1);
else
{
VOID(table->file->extra(HA_EXTRA_WRITE_CACHE));
empty_record(table);
}
join->tmp_table= table; /* Save for easy recursion */
join->fields= fields;
/* Set up select_end */
if (table)
{
if (table->group && join->tmp_table_param.sum_func_count)
{
if (table->keys)
{
DBUG_PRINT("info",("Using end_update"));
end_select=end_update;
if (!table->file->inited)
table->file->ha_index_init(0);
}
else
{
DBUG_PRINT("info",("Using end_unique_update"));
end_select=end_unique_update;
}
}
else if (join->sort_and_group)
{
DBUG_PRINT("info",("Using end_write_group"));
end_select=end_write_group;
}
else
{
DBUG_PRINT("info",("Using end_write"));
end_select=end_write;
}
}
else
{
if (join->sort_and_group || (join->procedure &&
join->procedure->flags & PROC_GROUP))
end_select=end_send_group;
else
end_select=end_send;
}
if (join->tables)
{
join->join_tab[join->tables-1].next_select=end_select;
join_tab=join->join_tab+join->const_tables;
}
join->send_records=0;
if (join->tables == join->const_tables)
{
/*
HAVING will be chcked after processing aggregate functions,
But WHERE should checkd here (we alredy have read tables)
*/
if (!join->conds || join->conds->val_int())
{
if (!(error=(*end_select)(join,join_tab,0)) || error == -3)
error=(*end_select)(join,join_tab,1);
}
else if (join->send_row_on_empty_set())
error= join->result->send_data(*columns_list);
}
else
{
DBUG_ASSERT(join_tab);
error= sub_select(join,join_tab,0);
if (error >= 0)
error= sub_select(join,join_tab,1);
if (error == -3)
error= 0; /* select_limit used */
}
if (error >= 0)
{
error=0;
if (!table) // If sending data to client
{
/*
The following will unlock all cursors if the command wasn't an
update command
*/
join->join_free(0); // Unlock all cursors
if (join->result->send_eof())
error= 1; // Don't send error
}
DBUG_PRINT("info",("%ld records output",join->send_records));
}
if (table)
{
int tmp, new_errno= 0;
if ((tmp=table->file->extra(HA_EXTRA_NO_CACHE)))
{
DBUG_PRINT("error",("extra(HA_EXTRA_NO_CACHE) failed"));
new_errno= tmp;
}
if ((tmp=table->file->ha_index_or_rnd_end()))
{
DBUG_PRINT("error",("ha_index_or_rnd_end() failed"));
new_errno= tmp;
}
if (new_errno)
table->file->print_error(new_errno,MYF(0));
}
#ifndef DBUG_OFF
if (error)
{
DBUG_PRINT("error",("Error: do_select() failed"));
}
#endif
DBUG_RETURN(join->thd->net.report_error ? -1 : error);
}
static int
sub_select_cache(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
int error;
if (end_of_records)
{
if ((error=flush_cached_records(join,join_tab,FALSE)) < 0)
return error; /* purecov: inspected */
return sub_select(join,join_tab,end_of_records);
}
if (join->thd->killed) // If aborted by user
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
return -2; /* purecov: inspected */
}
if (join_tab->use_quick != 2 || test_if_quick_select(join_tab) <= 0)
{
if (!store_record_in_cache(&join_tab->cache))
return 0; // There is more room in cache
return flush_cached_records(join,join_tab,FALSE);
}
if ((error=flush_cached_records(join,join_tab,TRUE)) < 0)
return error; /* purecov: inspected */
return sub_select(join,join_tab,end_of_records); /* Use ordinary select */
}
static int
sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
join_tab->table->null_row=0;
if (end_of_records)
return (*join_tab->next_select)(join,join_tab+1,end_of_records);
/* Cache variables for faster loop */
int error;
bool found=0;
COND *on_expr=join_tab->on_expr, *select_cond=join_tab->select_cond;
my_bool *report_error= &(join->thd->net.report_error);
if (!(error=(*join_tab->read_first_record)(join_tab)))
{
bool not_exists_optimize= join_tab->table->reginfo.not_exists_optimize;
bool not_used_in_distinct=join_tab->not_used_in_distinct;
ha_rows found_records=join->found_records;
READ_RECORD *info= &join_tab->read_record;
join->thd->row_count= 0;
do
{
if (join->thd->killed) // Aborted by user
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
return -2; /* purecov: inspected */
}
join->examined_rows++;
DBUG_PRINT("counts", ("join->examined_rows++: %lu",
(ulong) join->examined_rows));
join->thd->row_count++;
if (!on_expr || on_expr->val_int())
{
found=1;
if (not_exists_optimize)
break; // Searching after not null columns
if (!select_cond || select_cond->val_int())
{
if ((error=(*join_tab->next_select)(join,join_tab+1,0)) < 0)
return error;
/*
Test if this was a SELECT DISTINCT query on a table that
was not in the field list; In this case we can abort if
we found a row, as no new rows can be added to the result.
*/
if (not_used_in_distinct && found_records != join->found_records)
return 0;
}
else
{
/*
This row failed selection, release lock on it.
XXX: There is no table handler in MySQL which makes use of this
call. It's kept from Gemini times. A lot of new code was added
recently (i. e. subselects) without having it in mind.
*/
info->file->unlock_row();
}
}
} while (!(error=info->read_record(info)) && !(*report_error));
}
if (error > 0 || (*report_error)) // Fatal error
return -1;
if (!found && on_expr)
{ // OUTER JOIN
restore_record(join_tab->table,default_values); // Make empty record
mark_as_null_row(join_tab->table); // For group by without error
if (!select_cond || select_cond->val_int())
{
if ((error=(*join_tab->next_select)(join,join_tab+1,0)) < 0)
return error; /* purecov: inspected */
}
}
return 0;
}
static int
flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skip_last)
{
int error;
READ_RECORD *info;
if (!join_tab->cache.records)
return 0; /* Nothing to do */
if (skip_last)
(void) store_record_in_cache(&join_tab->cache); // Must save this for later
if (join_tab->use_quick == 2)
{
if (join_tab->select->quick)
{ /* Used quick select last. reset it */
delete join_tab->select->quick;
join_tab->select->quick=0;
}
}
/* read through all records */
if ((error=join_init_read_record(join_tab)))
{
reset_cache_write(&join_tab->cache);
return -error; /* No records or error */
}
for (JOIN_TAB *tmp=join->join_tab; tmp != join_tab ; tmp++)
{
tmp->status=tmp->table->status;
tmp->table->status=0;
}
info= &join_tab->read_record;
do
{
if (join->thd->killed)
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
return -2; // Aborted by user /* purecov: inspected */
}
SQL_SELECT *select=join_tab->select;
if (!error && (!join_tab->cache.select ||
!join_tab->cache.select->skip_record()))
{
uint i;
reset_cache_read(&join_tab->cache);
for (i=(join_tab->cache.records- (skip_last ? 1 : 0)) ; i-- > 0 ;)
{
read_cached_record(join_tab);
if (!select || !select->skip_record())
if ((error=(join_tab->next_select)(join,join_tab+1,0)) < 0)
{
reset_cache_write(&join_tab->cache);
return error; /* purecov: inspected */
}
}
}
} while (!(error=info->read_record(info)));
if (skip_last)
read_cached_record(join_tab); // Restore current record
reset_cache_write(&join_tab->cache);
if (error > 0) // Fatal error
return -1; /* purecov: inspected */
for (JOIN_TAB *tmp2=join->join_tab; tmp2 != join_tab ; tmp2++)
tmp2->table->status=tmp2->status;
return 0;
}
/*****************************************************************************
The different ways to read a record
Returns -1 if row was not found, 0 if row was found and 1 on errors
*****************************************************************************/
/* Help function when we get some an error from the table handler */
int report_error(TABLE *table, int error)
{
if (error == HA_ERR_END_OF_FILE || error == HA_ERR_KEY_NOT_FOUND)
{
table->status= STATUS_GARBAGE;
return -1; // key not found; ok
}
/*
Locking reads can legally return also these errors, do not
print them to the .err log
*/
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("Got error %d when reading table '%s'",
error, table->path);
table->file->print_error(error,MYF(0));
return 1;
}
int safe_index_read(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;
if ((error=table->file->index_read(table->record[0],
tab->ref.key_buff,
tab->ref.key_length, HA_READ_KEY_EXACT)))
return report_error(table, error);
return 0;
}
static int
join_read_const_table(JOIN_TAB *tab, POSITION *pos)
{
int error;
DBUG_ENTER("join_read_const_table");
TABLE *table=tab->table;
table->const_table=1;
table->null_row=0;
table->status=STATUS_NO_RECORD;
if (tab->type == JT_SYSTEM)
{
if ((error=join_read_system(tab)))
{ // Info for DESCRIBE
tab->info="const row not found";
/* Mark for EXPLAIN that the row was not found */
pos->records_read=0.0;
if (!table->outer_join || error > 0)
DBUG_RETURN(error);
}
}
else
{
if (!table->key_read && table->used_keys.is_set(tab->ref.key) &&
!table->no_keyread &&
(int) table->reginfo.lock_type <= (int) TL_READ_HIGH_PRIORITY)
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
tab->index= tab->ref.key;
}
if ((error=join_read_const(tab)))
{
tab->info="unique row not found";
/* Mark for EXPLAIN that the row was not found */
pos->records_read=0.0;
if (!table->outer_join || error > 0)
DBUG_RETURN(error);
}
if (table->key_read)
{
table->key_read=0;
table->file->extra(HA_EXTRA_NO_KEYREAD);
}
}
if (tab->on_expr && !table->null_row)
{
if ((table->null_row= test(tab->on_expr->val_int() == 0)))
mark_as_null_row(table);
}
if (!table->null_row)
table->maybe_null=0;
DBUG_RETURN(0);
}
static int
join_read_system(JOIN_TAB *tab)
{
TABLE *table= tab->table;
int error;
if (table->status & STATUS_GARBAGE) // If first read
{
if ((error=table->file->read_first_row(table->record[0],
table->primary_key)))
{
if (error != HA_ERR_END_OF_FILE)
return report_error(table, error);
mark_as_null_row(tab->table);
empty_record(table); // Make empty record
return -1;
}
store_record(table,record[1]);
}
else if (!table->status) // Only happens with left join
restore_record(table,record[1]); // restore old record
table->null_row=0;
return table->status ? -1 : 0;
}
static int
join_read_const(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;
if (table->status & STATUS_GARBAGE) // If first read
{
if (cp_buffer_from_ref(tab->join->thd, &tab->ref))
error=HA_ERR_KEY_NOT_FOUND;
else
{
error=table->file->index_read_idx(table->record[0],tab->ref.key,
(byte*) tab->ref.key_buff,
tab->ref.key_length,HA_READ_KEY_EXACT);
}
if (error)
{
mark_as_null_row(tab->table);
empty_record(table);
if (error != HA_ERR_KEY_NOT_FOUND)
return report_error(table, error);
return -1;
}
store_record(table,record[1]);
}
else if (!(table->status & ~STATUS_NULL_ROW)) // Only happens with left join
{
table->status=0;
restore_record(table,record[1]); // restore old record
}
table->null_row=0;
return table->status ? -1 : 0;
}
static int
join_read_key(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;
if (!table->file->inited)
table->file->ha_index_init(tab->ref.key);
if (cmp_buffer_with_ref(tab) ||
(table->status & (STATUS_GARBAGE | STATUS_NO_PARENT | STATUS_NULL_ROW)))
{
if (tab->ref.key_err)
{
table->status=STATUS_NOT_FOUND;
return -1;
}
error=table->file->index_read(table->record[0],
tab->ref.key_buff,
tab->ref.key_length,HA_READ_KEY_EXACT);
if (error && error != HA_ERR_KEY_NOT_FOUND)
return report_error(table, error);
}
table->null_row=0;
return table->status ? -1 : 0;
}
static int
join_read_always_key(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;
for (uint i= 0 ; i < tab->ref.key_parts ; i++)
{
if ((tab->ref.null_rejecting & 1 << i) && tab->ref.items[i]->is_null())
return -1;
}
if (!table->file->inited)
table->file->ha_index_init(tab->ref.key);
if (cp_buffer_from_ref(tab->join->thd, &tab->ref))
return -1;
if ((error=table->file->index_read(table->record[0],
tab->ref.key_buff,
tab->ref.key_length,HA_READ_KEY_EXACT)))
{
if (error != HA_ERR_KEY_NOT_FOUND)
return report_error(table, error);
return -1; /* purecov: inspected */
}
return 0;
}
/*
This function is used when optimizing away ORDER BY in
SELECT * FROM t1 WHERE a=1 ORDER BY a DESC,b DESC
*/
static int
join_read_last_key(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;
if (!table->file->inited)
table->file->ha_index_init(tab->ref.key);
if (cp_buffer_from_ref(tab->join->thd, &tab->ref))
return -1;
if ((error=table->file->index_read_last(table->record[0],
tab->ref.key_buff,
tab->ref.key_length)))
{
if (error != HA_ERR_KEY_NOT_FOUND)
return report_error(table, error);
return -1; /* purecov: inspected */
}
return 0;
}
/* ARGSUSED */
static int
join_no_more_records(READ_RECORD *info __attribute__((unused)))
{
return -1;
}
static int
join_read_next_same(READ_RECORD *info)
{
int error;
TABLE *table= info->table;
JOIN_TAB *tab=table->reginfo.join_tab;
if ((error=table->file->index_next_same(table->record[0],
tab->ref.key_buff,
tab->ref.key_length)))
{
if (error != HA_ERR_END_OF_FILE)
return report_error(table, error);
table->status= STATUS_GARBAGE;
return -1;
}
return 0;
}
static int
join_read_prev_same(READ_RECORD *info)
{
int error;
TABLE *table= info->table;
JOIN_TAB *tab=table->reginfo.join_tab;
if ((error=table->file->index_prev(table->record[0])))
return report_error(table, error);
if (key_cmp_if_same(table, tab->ref.key_buff, tab->ref.key,
tab->ref.key_length))
{
table->status=STATUS_NOT_FOUND;
error= -1;
}
return error;
}
static int
join_init_quick_read_record(JOIN_TAB *tab)
{
if (test_if_quick_select(tab) == -1)
return -1; /* No possible records */
return join_init_read_record(tab);
}
static int
test_if_quick_select(JOIN_TAB *tab)
{
delete tab->select->quick;
tab->select->quick=0;
return tab->select->test_quick_select(tab->join->thd, tab->keys,
(table_map) 0, HA_POS_ERROR, 0);
}
static int
join_init_read_record(JOIN_TAB *tab)
{
if (tab->select && tab->select->quick)
tab->select->quick->reset();
init_read_record(&tab->read_record, tab->join->thd, tab->table,
tab->select,1,1);
return (*tab->read_record.read_record)(&tab->read_record);
}
static int
join_read_first(JOIN_TAB *tab)
{
int error;
TABLE *table=tab->table;
if (!table->key_read && table->used_keys.is_set(tab->index) &&
!table->no_keyread)
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
tab->table->status=0;
tab->read_record.read_record=join_read_next;
tab->read_record.table=table;
tab->read_record.file=table->file;
tab->read_record.index=tab->index;
tab->read_record.record=table->record[0];
if (!table->file->inited)
table->file->ha_index_init(tab->index);
if ((error=tab->table->file->index_first(tab->table->record[0])))
{
if (error != HA_ERR_KEY_NOT_FOUND && error != HA_ERR_END_OF_FILE)
report_error(table, error);
return -1;
}
return 0;
}
static int
join_read_next(READ_RECORD *info)
{
int error;
if ((error=info->file->index_next(info->record)))
return report_error(info->table, error);
return 0;
}
static int
join_read_last(JOIN_TAB *tab)
{
TABLE *table=tab->table;
int error;
if (!table->key_read && table->used_keys.is_set(tab->index) &&
!table->no_keyread)
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
tab->table->status=0;
tab->read_record.read_record=join_read_prev;
tab->read_record.table=table;
tab->read_record.file=table->file;
tab->read_record.index=tab->index;
tab->read_record.record=table->record[0];
if (!table->file->inited)
table->file->ha_index_init(tab->index);
if ((error= tab->table->file->index_last(tab->table->record[0])))
return report_error(table, error);
return 0;
}
static int
join_read_prev(READ_RECORD *info)
{
int error;
if ((error= info->file->index_prev(info->record)))
return report_error(info->table, error);
return 0;
}
static int
join_ft_read_first(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;
if (!table->file->inited)
table->file->ha_index_init(tab->ref.key);
#if NOT_USED_YET
if (cp_buffer_from_ref(tab->join->thd, &tab->ref)) // as ft-key doesn't use store_key's
return -1; // see also FT_SELECT::init()
#endif
table->file->ft_init();
if ((error= table->file->ft_read(table->record[0])))
return report_error(table, error);
return 0;
}
static int
join_ft_read_next(READ_RECORD *info)
{
int error;
if ((error= info->file->ft_read(info->table->record[0])))
return report_error(info->table, error);
return 0;
}
/*
Reading of key with key reference and one part that may be NULL
*/
static int
join_read_always_key_or_null(JOIN_TAB *tab)
{
int res;
/* First read according to key which is NOT NULL */
*tab->ref.null_ref_key= 0; // Clear null byte
if ((res= join_read_always_key(tab)) >= 0)
return res;
/* Then read key with null value */
*tab->ref.null_ref_key= 1; // Set null byte
return safe_index_read(tab);
}
static int
join_read_next_same_or_null(READ_RECORD *info)
{
int error;
if ((error= join_read_next_same(info)) >= 0)
return error;
JOIN_TAB *tab= info->table->reginfo.join_tab;
/* Test if we have already done a read after null key */
if (*tab->ref.null_ref_key)
return -1; // All keys read
*tab->ref.null_ref_key= 1; // Set null byte
return safe_index_read(tab); // then read null keys
}
/*****************************************************************************
The different end of select functions
These functions returns < 0 when end is reached, 0 on ok and > 0 if a
fatal error (like table corruption) was detected
*****************************************************************************/
/* ARGSUSED */
static int
end_send(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
DBUG_ENTER("end_send");
if (!end_of_records)
{
int error;
if (join->having && join->having->val_int() == 0)
DBUG_RETURN(0); // Didn't match having
error=0;
if (join->procedure)
error=join->procedure->send_row(join->procedure_fields_list);
else if (join->do_send_rows)
error=join->result->send_data(*join->fields);
if (error)
DBUG_RETURN(-1); /* purecov: inspected */
if (++join->send_records >= join->unit->select_limit_cnt &&
join->do_send_rows)
{
if (join->select_options & OPTION_FOUND_ROWS)
{
JOIN_TAB *jt=join->join_tab;
if ((join->tables == 1) && !join->tmp_table && !join->sort_and_group
&& !join->send_group_parts && !join->having && !jt->select_cond &&
!(jt->select && jt->select->quick) &&
!(jt->table->file->table_flags() & HA_NOT_EXACT_COUNT) &&
(jt->ref.key < 0))
{
/* Join over all rows in table; Return number of found rows */
TABLE *table=jt->table;
join->select_options ^= OPTION_FOUND_ROWS;
if (table->sort.record_pointers ||
(table->sort.io_cache && my_b_inited(table->sort.io_cache)))
{
/* Using filesort */
join->send_records= table->sort.found_records;
}
else
{
table->file->info(HA_STATUS_VARIABLE);
join->send_records = table->file->records;
}
}
else
{
join->do_send_rows= 0;
if (join->unit->fake_select_lex)
join->unit->fake_select_lex->select_limit= HA_POS_ERROR;
DBUG_RETURN(0);
}
}
DBUG_RETURN(-3); // Abort nicely
}
}
else
{
if (join->procedure && join->procedure->end_of_records())
DBUG_RETURN(-1);
}
DBUG_RETURN(0);
}
/* ARGSUSED */
static int
end_send_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
int idx= -1;
DBUG_ENTER("end_send_group");
if (!join->first_record || end_of_records ||
(idx=test_if_group_changed(join->group_fields)) >= 0)
{
if (join->first_record || (end_of_records && !join->group))
{
if (join->procedure)
join->procedure->end_group();
if (idx < (int) join->send_group_parts)
{
int error=0;
if (join->procedure)
{
if (join->having && join->having->val_int() == 0)
error= -1; // Didn't satisfy having
else
{
if (join->do_send_rows)
error=join->procedure->send_row(*join->fields) ? 1 : 0;
join->send_records++;
}
if (end_of_records && join->procedure->end_of_records())
error= 1; // Fatal error
}
else
{
if (!join->first_record)
{
List_iterator_fast<Item> it(*join->fields);
Item *item;
/* No matching rows for group function */
join->clear();
while ((item= it++))
item->no_rows_in_result();
}
if (join->having && join->having->val_int() == 0)
error= -1; // Didn't satisfy having
else
{
if (join->do_send_rows)
error=join->result->send_data(*join->fields) ? 1 : 0;
join->send_records++;
}
if (join->rollup.state != ROLLUP::STATE_NONE && error <= 0)
{
if (join->rollup_send_data((uint) (idx+1)))
error= 1;
}
}
if (error > 0)
DBUG_RETURN(-1); /* purecov: inspected */
if (end_of_records)
DBUG_RETURN(0);
if (join->send_records >= join->unit->select_limit_cnt &&
join->do_send_rows)
{
if (!(join->select_options & OPTION_FOUND_ROWS))
DBUG_RETURN(-3); // Abort nicely
join->do_send_rows=0;
join->unit->select_limit_cnt = HA_POS_ERROR;
}
}
}
else
{
if (end_of_records)
DBUG_RETURN(0);
join->first_record=1;
VOID(test_if_group_changed(join->group_fields));
}
if (idx < (int) join->send_group_parts)
{
copy_fields(&join->tmp_table_param);
if (init_sum_functions(join->sum_funcs, join->sum_funcs_end[idx+1]))
DBUG_RETURN(-1);
if (join->procedure)
join->procedure->add();
DBUG_RETURN(0);
}
}
if (update_sum_func(join->sum_funcs))
DBUG_RETURN(-1);
if (join->procedure)
join->procedure->add();
DBUG_RETURN(0);
}
/* ARGSUSED */
static int
end_write(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
TABLE *table=join->tmp_table;
int error;
DBUG_ENTER("end_write");
if (join->thd->killed) // Aborted by user
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-2); /* purecov: inspected */
}
if (!end_of_records)
{
copy_fields(&join->tmp_table_param);
copy_funcs(join->tmp_table_param.items_to_copy);
#ifdef TO_BE_DELETED
if (!table->uniques) // If not unique handling
{
/* Copy null values from group to row */
ORDER *group;
for (group=table->group ; group ; group=group->next)
{
Item *item= *group->item;
if (item->maybe_null)
{
Field *field=item->get_tmp_table_field();
field->ptr[-1]= (byte) (field->is_null() ? 1 : 0);
}
}
}
#endif
if (!join->having || join->having->val_int())
{
join->found_records++;
if ((error=table->file->write_row(table->record[0])))
{
if (error == HA_ERR_FOUND_DUPP_KEY ||
error == HA_ERR_FOUND_DUPP_UNIQUE)
goto end;
if (create_myisam_from_heap(join->thd, table, &join->tmp_table_param,
error,1))
DBUG_RETURN(-1); // Not a table_is_full error
table->uniques=0; // To ensure rows are the same
}
if (++join->send_records >= join->tmp_table_param.end_write_records &&
join->do_send_rows)
{
if (!(join->select_options & OPTION_FOUND_ROWS))
DBUG_RETURN(-3);
join->do_send_rows=0;
join->unit->select_limit_cnt = HA_POS_ERROR;
DBUG_RETURN(0);
}
}
}
end:
DBUG_RETURN(0);
}
/* Group by searching after group record and updating it if possible */
/* ARGSUSED */
static int
end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
TABLE *table=join->tmp_table;
ORDER *group;
int error;
DBUG_ENTER("end_update");
if (end_of_records)
DBUG_RETURN(0);
if (join->thd->killed) // Aborted by user
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-2); /* purecov: inspected */
}
join->found_records++;
copy_fields(&join->tmp_table_param); // Groups are copied twice.
/* Make a key of group index */
for (group=table->group ; group ; group=group->next)
{
Item *item= *group->item;
item->save_org_in_field(group->field);
#ifdef EMBEDDED_LIBRARY
join->thd->net.last_errno= 0;
#endif
/* Store in the used key if the field was 0 */
if (item->maybe_null)
group->buff[-1]=item->null_value ? 1 : 0;
}
if (!table->file->index_read(table->record[1],
join->tmp_table_param.group_buff,0,
HA_READ_KEY_EXACT))
{ /* Update old record */
restore_record(table,record[1]);
update_tmptable_sum_func(join->sum_funcs,table);
if ((error=table->file->update_row(table->record[1],
table->record[0])))
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
DBUG_RETURN(0);
}
/* The null bits are already set */
KEY_PART_INFO *key_part;
for (group=table->group,key_part=table->key_info[0].key_part;
group ;
group=group->next,key_part++)
memcpy(table->record[0]+key_part->offset, group->buff, key_part->length);
init_tmptable_sum_functions(join->sum_funcs);
copy_funcs(join->tmp_table_param.items_to_copy);
if ((error=table->file->write_row(table->record[0])))
{
if (create_myisam_from_heap(join->thd, table, &join->tmp_table_param,
error, 0))
DBUG_RETURN(-1); // Not a table_is_full error
/* Change method to update rows */
table->file->ha_index_init(0);
join->join_tab[join->tables-1].next_select=end_unique_update;
}
join->send_records++;
DBUG_RETURN(0);
}
/* Like end_update, but this is done with unique constraints instead of keys */
static int
end_unique_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
TABLE *table=join->tmp_table;
int error;
DBUG_ENTER("end_unique_update");
if (end_of_records)
DBUG_RETURN(0);
if (join->thd->killed) // Aborted by user
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-2); /* purecov: inspected */
}
init_tmptable_sum_functions(join->sum_funcs);
copy_fields(&join->tmp_table_param); // Groups are copied twice.
copy_funcs(join->tmp_table_param.items_to_copy);
if (!(error=table->file->write_row(table->record[0])))
join->send_records++; // New group
else
{
if ((int) table->file->get_dup_key(error) < 0)
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
if (table->file->rnd_pos(table->record[1],table->file->dupp_ref))
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
restore_record(table,record[1]);
update_tmptable_sum_func(join->sum_funcs,table);
if ((error=table->file->update_row(table->record[1],
table->record[0])))
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
}
DBUG_RETURN(0);
}
/* ARGSUSED */
static int
end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
TABLE *table=join->tmp_table;
int error;
int idx= -1;
DBUG_ENTER("end_write_group");
if (join->thd->killed)
{ // Aborted by user
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-2); /* purecov: inspected */
}
if (!join->first_record || end_of_records ||
(idx=test_if_group_changed(join->group_fields)) >= 0)
{
if (join->first_record || (end_of_records && !join->group))
{
if (join->procedure)
join->procedure->end_group();
int send_group_parts= join->send_group_parts;
if (idx < send_group_parts)
{
if (!join->first_record)
{
/* No matching rows for group function */
join->clear();
}
copy_sum_funcs(join->sum_funcs,
join->sum_funcs_end[send_group_parts]);
if (join->having && join->having->val_int() == 0)
error= -1;
else if ((error=table->file->write_row(table->record[0])))
{
if (create_myisam_from_heap(join->thd, table,
&join->tmp_table_param,
error, 0))
DBUG_RETURN(-1);
/*
If table->file->write_row() was failed because of 'out of memory'
and tmp table succesfully created, reset error.
*/
error=0;
}
if (join->rollup.state != ROLLUP::STATE_NONE && error <= 0)
{
if (join->rollup_write_data((uint) (idx+1), table))
error= 1;
}
if (error > 0)
DBUG_RETURN(-1);
if (end_of_records)
DBUG_RETURN(0);
}
}
else
{
if (end_of_records)
DBUG_RETURN(0);
join->first_record=1;
VOID(test_if_group_changed(join->group_fields));
}
if (idx < (int) join->send_group_parts)
{
copy_fields(&join->tmp_table_param);
copy_funcs(join->tmp_table_param.items_to_copy);
if (init_sum_functions(join->sum_funcs, join->sum_funcs_end[idx+1]))
DBUG_RETURN(-1);
if (join->procedure)
join->procedure->add();
DBUG_RETURN(0);
}
}
if (update_sum_func(join->sum_funcs))
DBUG_RETURN(-1);
if (join->procedure)
join->procedure->add();
DBUG_RETURN(0);
}
/*****************************************************************************
Remove calculation with tables that aren't yet read. Remove also tests
against fields that are read through key where the table is not a
outer join table.
We can't remove tests that are made against columns which are stored
in sorted order.
*****************************************************************************/
/* Return 1 if right_item is used removable reference key on left_item */
static bool test_if_ref(Item_field *left_item,Item *right_item)
{
Field *field=left_item->field;
// No need to change const test. We also have to keep tests on LEFT JOIN
if (!field->table->const_table && !field->table->maybe_null)
{
Item *ref_item=part_of_refkey(field->table,field);
if (ref_item && ref_item->eq(right_item,1))
{
if (right_item->type() == Item::FIELD_ITEM)
return (field->eq_def(((Item_field *) right_item)->field));
if (right_item->const_item() && !(right_item->is_null()))
{
/*
We can remove binary fields and numerical fields except float,
as float comparison isn't 100 % secure
We have to keep binary strings to be able to check for end spaces
*/
if (field->binary() &&
field->real_type() != FIELD_TYPE_STRING &&
field->real_type() != FIELD_TYPE_VAR_STRING &&
(field->type() != FIELD_TYPE_FLOAT || field->decimals() == 0))
{
return !store_val_in_field(field, right_item, CHECK_FIELD_WARN);
}
}
}
}
return 0; // keep test
}
static COND *
make_cond_for_table(COND *cond, table_map tables, table_map used_table)
{
if (used_table && !(cond->used_tables() & used_table))
return (COND*) 0; // Already checked
if (cond->type() == Item::COND_ITEM)
{
if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
{
/* Create new top level AND item */
Item_cond_and *new_cond=new Item_cond_and;
if (!new_cond)
return (COND*) 0; // OOM /* purecov: inspected */
List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
Item *item;
while ((item=li++))
{
Item *fix=make_cond_for_table(item,tables,used_table);
if (fix)
new_cond->argument_list()->push_back(fix);
}
switch (new_cond->argument_list()->elements) {
case 0:
return (COND*) 0; // Always true
case 1:
return new_cond->argument_list()->head();
default:
/*
Item_cond_and do not need fix_fields for execution, its parameters
are fixed or do not need fix_fields, too
*/
new_cond->quick_fix_field();
new_cond->used_tables_cache=
((Item_cond_and*) cond)->used_tables_cache &
tables;
return new_cond;
}
}
else
{ // Or list
Item_cond_or *new_cond=new Item_cond_or;
if (!new_cond)
return (COND*) 0; // OOM /* purecov: inspected */
List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
Item *item;
while ((item=li++))
{
Item *fix=make_cond_for_table(item,tables,0L);
if (!fix)
return (COND*) 0; // Always true
new_cond->argument_list()->push_back(fix);
}
/*
Item_cond_and do not need fix_fields for execution, its parameters
are fixed or do not need fix_fields, too
*/
new_cond->quick_fix_field();
new_cond->used_tables_cache= ((Item_cond_or*) cond)->used_tables_cache;
new_cond->top_level_item();
return new_cond;
}
}
/*
Because the following test takes a while and it can be done
table_count times, we mark each item that we have examined with the result
of the test
*/
if (cond->marker == 3 || (cond->used_tables() & ~tables))
return (COND*) 0; // Can't check this yet
if (cond->marker == 2 || cond->eq_cmp_result() == Item::COND_OK)
return cond; // Not boolean op
if (((Item_func*) cond)->functype() == Item_func::EQ_FUNC)
{
Item *left_item= ((Item_func*) cond)->arguments()[0];
Item *right_item= ((Item_func*) cond)->arguments()[1];
if (left_item->type() == Item::FIELD_ITEM &&
test_if_ref((Item_field*) left_item,right_item))
{
cond->marker=3; // Checked when read
return (COND*) 0;
}
if (right_item->type() == Item::FIELD_ITEM &&
test_if_ref((Item_field*) right_item,left_item))
{
cond->marker=3; // Checked when read
return (COND*) 0;
}
}
cond->marker=2;
return cond;
}
static Item *
part_of_refkey(TABLE *table,Field *field)
{
if (!table->reginfo.join_tab)
return (Item*) 0; // field from outer non-select (UPDATE,...)
uint ref_parts=table->reginfo.join_tab->ref.key_parts;
if (ref_parts)
{
KEY_PART_INFO *key_part=
table->key_info[table->reginfo.join_tab->ref.key].key_part;
for (uint part=0 ; part < ref_parts ; part++,key_part++)
if (field->eq(key_part->field) &&
!(key_part->key_part_flag & (HA_PART_KEY_SEG | HA_NULL_PART)))
return table->reginfo.join_tab->ref.items[part];
}
return (Item*) 0;
}
/*****************************************************************************
Test if one can use the key to resolve ORDER BY
SYNOPSIS
test_if_order_by_key()
order Sort order
table Table to sort
idx Index to check
used_key_parts Return value for used key parts.
NOTES
used_key_parts is set to correct key parts used if return value != 0
(On other cases, used_key_part may be changed)
RETURN
1 key is ok.
0 Key can't be used
-1 Reverse key can be used
*****************************************************************************/
static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
uint *used_key_parts)
{
KEY_PART_INFO *key_part,*key_part_end;
key_part=table->key_info[idx].key_part;
key_part_end=key_part+table->key_info[idx].key_parts;
key_part_map const_key_parts=table->const_key_parts[idx];
int reverse=0;
DBUG_ENTER("test_if_order_by_key");
for (; order ; order=order->next, const_key_parts>>=1)
{
Field *field=((Item_field*) (*order->item))->field;
int flag;
/*
Skip key parts that are constants in the WHERE clause.
These are already skipped in the ORDER BY by const_expression_in_where()
*/
for (; const_key_parts & 1 ; const_key_parts>>= 1)
key_part++;
if (key_part == key_part_end || key_part->field != field)
DBUG_RETURN(0);
/* set flag to 1 if we can use read-next on key, else to -1 */
flag= ((order->asc == !(key_part->key_part_flag & HA_REVERSE_SORT)) ?
1 : -1);
if (reverse && flag != reverse)
DBUG_RETURN(0);
reverse=flag; // Remember if reverse
key_part++;
}
*used_key_parts= (uint) (key_part - table->key_info[idx].key_part);
if (reverse == -1 && !(table->file->index_flags(idx, *used_key_parts-1, 1) &
HA_READ_PREV))
reverse= 0; // Index can't be used
DBUG_RETURN(reverse);
}
static uint find_shortest_key(TABLE *table, const key_map *usable_keys)
{
uint min_length= (uint) ~0;
uint best= MAX_KEY;
if (!usable_keys->is_clear_all())
{
for (uint nr=0; nr < table->keys ; nr++)
{
if (usable_keys->is_set(nr))
{
if (table->key_info[nr].key_length < min_length)
{
min_length=table->key_info[nr].key_length;
best=nr;
}
}
}
}
return best;
}
/*
Test if a second key is the subkey of the first one.
SYNOPSIS
is_subkey()
key_part First key parts
ref_key_part Second key parts
ref_key_part_end Last+1 part of the second key
NOTE
Second key MUST be shorter than the first one.
RETURN
1 is a subkey
0 no sub key
*/
inline bool
is_subkey(KEY_PART_INFO *key_part, KEY_PART_INFO *ref_key_part,
KEY_PART_INFO *ref_key_part_end)
{
for (; ref_key_part < ref_key_part_end; key_part++, ref_key_part++)
if (!key_part->field->eq(ref_key_part->field))
return 0;
return 1;
}
/*
Test if we can use one of the 'usable_keys' instead of 'ref' key for sorting
SYNOPSIS
test_if_subkey()
ref Number of key, used for WHERE clause
usable_keys Keys for testing
RETURN
MAX_KEY If we can't use other key
the number of found key Otherwise
*/
static uint
test_if_subkey(ORDER *order, TABLE *table, uint ref, uint ref_key_parts,
const key_map *usable_keys)
{
uint nr;
uint min_length= (uint) ~0;
uint best= MAX_KEY;
uint not_used;
KEY_PART_INFO *ref_key_part= table->key_info[ref].key_part;
KEY_PART_INFO *ref_key_part_end= ref_key_part + ref_key_parts;
for (nr= 0 ; nr < table->keys ; nr++)
{
if (usable_keys->is_set(nr) &&
table->key_info[nr].key_length < min_length &&
table->key_info[nr].key_parts >= ref_key_parts &&
is_subkey(table->key_info[nr].key_part, ref_key_part,
ref_key_part_end) &&
test_if_order_by_key(order, table, nr, &not_used))
{
min_length= table->key_info[nr].key_length;
best= nr;
}
}
return best;
}
/*
Check if GROUP BY/DISTINCT can be optimized away because the set is
already known to be distinct.
SYNOPSIS
list_contains_unique_index ()
table The table to operate on.
find_func function to iterate over the list and search
for a field
DESCRIPTION
Used in removing the GROUP BY/DISTINCT of the following types of
statements:
SELECT [DISTINCT] <unique_key_cols>... FROM <single_table_ref>
[GROUP BY <unique_key_cols>,...]
If (a,b,c is distinct)
then <any combination of a,b,c>,{whatever} is also distinct
This function checks if all the key parts of any of the unique keys
of the table are referenced by a list : either the select list
through find_field_in_item_list or GROUP BY list through
find_field_in_order_list.
If the above holds then we can safely remove the GROUP BY/DISTINCT,
as no result set can be more distinct than an unique key.
RETURN VALUE
1 found
0 not found.
*/
static bool
list_contains_unique_index(TABLE *table,
bool (*find_func) (Field *, void *), void *data)
{
for (uint keynr= 0; keynr < table->keys; keynr++)
{
if (keynr == table->primary_key ||
(table->key_info[keynr].flags & HA_NOSAME))
{
KEY *keyinfo= table->key_info + keynr;
KEY_PART_INFO *key_part, *key_part_end;
for (key_part=keyinfo->key_part,
key_part_end=key_part+ keyinfo->key_parts;
key_part < key_part_end;
key_part++)
{
if (!find_func(key_part->field, data))
break;
}
if (key_part == key_part_end)
return 1;
}
}
return 0;
}
/*
Helper function for list_contains_unique_index.
Find a field reference in a list of ORDER structures.
SYNOPSIS
find_field_in_order_list ()
field The field to search for.
data ORDER *.The list to search in
DESCRIPTION
Finds a direct reference of the Field in the list.
RETURN VALUE
1 found
0 not found.
*/
static bool
find_field_in_order_list (Field *field, void *data)
{
ORDER *group= (ORDER *) data;
bool part_found= 0;
for (ORDER *tmp_group= group; tmp_group; tmp_group=tmp_group->next)
{
Item *item= (*tmp_group->item)->real_item();
if (item->type() == Item::FIELD_ITEM &&
((Item_field*) item)->field->eq(field))
{
part_found= 1;
break;
}
}
return part_found;
}
/*
Helper function for list_contains_unique_index.
Find a field reference in a dynamic list of Items.
SYNOPSIS
find_field_in_item_list ()
field in The field to search for.
data in List<Item> *.The list to search in
DESCRIPTION
Finds a direct reference of the Field in the list.
RETURN VALUE
1 found
0 not found.
*/
static bool
find_field_in_item_list (Field *field, void *data)
{
List<Item> *fields= (List<Item> *) data;
bool part_found= 0;
List_iterator<Item> li(*fields);
Item *item;
while ((item= li++))
{
if (item->type() == Item::FIELD_ITEM &&
((Item_field*) item)->field->eq(field))
{
part_found= 1;
break;
}
}
return part_found;
}
/*
Test if we can skip the ORDER BY by using an index.
If we can use an index, the JOIN_TAB / tab->select struct
is changed to use the index.
Return:
0 We have to use filesort to do the sorting
1 We can use an index.
*/
static bool
test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
bool no_changes)
{
int ref_key;
uint ref_key_parts;
TABLE *table=tab->table;
SQL_SELECT *select=tab->select;
key_map usable_keys;
DBUG_ENTER("test_if_skip_sort_order");
LINT_INIT(ref_key_parts);
/*
Check which keys can be used to resolve ORDER BY.
We must not try to use disabled keys.
*/
usable_keys= table->keys_in_use;
for (ORDER *tmp_order=order; tmp_order ; tmp_order=tmp_order->next)
{
if ((*tmp_order->item)->type() != Item::FIELD_ITEM)
{
usable_keys.clear_all();
DBUG_RETURN(0);
}
usable_keys.intersect(((Item_field*) (*tmp_order->item))->
field->part_of_sortkey);
if (usable_keys.is_clear_all())
DBUG_RETURN(0); // No usable keys
}
ref_key= -1;
/* Test if constant range in WHERE */
if (tab->ref.key >= 0 && tab->ref.key_parts)
{
ref_key= tab->ref.key;
ref_key_parts= tab->ref.key_parts;
if (tab->type == JT_REF_OR_NULL || tab->type == JT_FT)
DBUG_RETURN(0);
}
else if (select && select->quick) // Range found by opt_range
{
ref_key= select->quick->index;
ref_key_parts= select->quick->used_key_parts;
}
if (ref_key >= 0)
{
/*
We come here when there is a REF key.
*/
int order_direction;
uint used_key_parts;
if (!usable_keys.is_set(ref_key))
{
/*
We come here when ref_key is not among usable_keys
*/
uint new_ref_key;
/*
If using index only read, only consider other possible index only
keys
*/
if (table->used_keys.is_set(ref_key))
usable_keys.intersect(table->used_keys);
if ((new_ref_key= test_if_subkey(order, table, ref_key, ref_key_parts,
&usable_keys)) < MAX_KEY)
{
/* Found key that can be used to retrieve data in sorted order */
if (tab->ref.key >= 0)
{
/*
We'll use ref access method on key new_ref_key. In general case
the index search tuple for new_ref_key will be different (e.g.
when one index is defined as (part1, part2, ...) and another as
(part1, part2(N), ...) and the WHERE clause contains
"part1 = const1 AND part2=const2".
So we build tab->ref from scratch here.
*/
KEYUSE *keyuse= tab->keyuse;
while (keyuse->key != new_ref_key && keyuse->table == tab->table)
keyuse++;
if (create_ref_for_key(tab->join, tab, keyuse,
tab->join->const_table_map))
DBUG_RETURN(0);
}
else
{
/*
The range optimizer constructed QUICK_RANGE for ref_key, and
we want to use instead new_ref_key as the index. We can't
just change the index of the quick select, because this may
result in an incosistent QUICK_SELECT object. Below we
create a new QUICK_SELECT from scratch so that all its
parameres are set correctly by the range optimizer.
*/
key_map new_ref_key_map;
new_ref_key_map.clear_all(); // Force the creation of quick select
new_ref_key_map.set_bit(new_ref_key); // only for new_ref_key.
if (select->test_quick_select(tab->join->thd, new_ref_key_map, 0,
(tab->join->select_options &
OPTION_FOUND_ROWS) ?
HA_POS_ERROR :
tab->join->unit->select_limit_cnt,0) <=
0)
DBUG_RETURN(0);
}
ref_key= new_ref_key;
}
}
/* Check if we get the rows in requested sorted order by using the key */
if (usable_keys.is_set(ref_key) &&
(order_direction = test_if_order_by_key(order,table,ref_key,
&used_key_parts)))
{
if (order_direction == -1) // If ORDER BY ... DESC
{
if (select && select->quick)
{
/*
Don't reverse the sort order, if it's already done.
(In some cases test_if_order_by_key() can be called multiple times
*/
if (!select->quick->reverse_sorted())
{
// ORDER BY range_key DESC
QUICK_SELECT_DESC *tmp=new QUICK_SELECT_DESC(select->quick,
used_key_parts);
if (!tmp || tmp->error)
{
delete tmp;
DBUG_RETURN(0); // Reverse sort not supported
}
select->quick=tmp;
}
DBUG_RETURN(1);
}
if (tab->ref.key_parts < used_key_parts)
{
/*
SELECT * FROM t1 WHERE a=1 ORDER BY a DESC,b DESC
Use a traversal function that starts by reading the last row
with key part (A) and then traverse the index backwards.
*/
tab->read_first_record= join_read_last_key;
tab->read_record.read_record= join_read_prev_same;
/* fall through */
}
}
else if (select && select->quick)
select->quick->sorted= 1;
DBUG_RETURN(1); /* No need to sort */
}
}
else
{
/* check if we can use a key to resolve the group */
/* Tables using JT_NEXT are handled here */
uint nr;
key_map keys;
/*
If not used with LIMIT, only use keys if the whole query can be
resolved with a key; This is because filesort() is usually faster than
retrieving all rows through an index.
*/
if (select_limit >= table->file->records)
{
keys= *table->file->keys_to_use_for_scanning();
keys.merge(table->used_keys);
/*
We are adding here also the index specified in FORCE INDEX clause,
if any.
This is to allow users to use index in ORDER BY.
*/
if (table->force_index)
keys.merge(table->keys_in_use_for_query);
keys.intersect(usable_keys);
}
else
keys= usable_keys;
for (nr=0; nr < table->keys ; nr++)
{
uint not_used;
if (keys.is_set(nr))
{
int flag;
if ((flag= test_if_order_by_key(order, table, nr, &not_used)))
{
if (!no_changes)
{
tab->index=nr;
tab->read_first_record= (flag > 0 ? join_read_first:
join_read_last);
tab->type=JT_NEXT; // Read with index_first(), index_next()
if (table->used_keys.is_set(nr))
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
}
DBUG_RETURN(1);
}
}
}
}
DBUG_RETURN(0); // Can't use index.
}
/*
If not selecting by given key, create an index how records should be read
SYNOPSIS
create_sort_index()
thd Thread handler
tab Table to sort (in join structure)
order How table should be sorted
filesort_limit Max number of rows that needs to be sorted
select_limit Max number of rows in final output
Used to decide if we should use index or not
IMPLEMENTATION
- If there is an index that can be used, 'tab' is modified to use
this index.
- If no index, create with filesort() an index file that can be used to
retrieve rows in order (should be done with 'read_record').
The sorted data is stored in tab->table and will be freed when calling
free_io_cache(tab->table).
RETURN VALUES
0 ok
-1 Some fatal error
1 No records
*/
static int
create_sort_index(THD *thd, JOIN *join, ORDER *order,
ha_rows filesort_limit, ha_rows select_limit)
{
SORT_FIELD *sortorder;
uint length;
ha_rows examined_rows;
TABLE *table;
SQL_SELECT *select;
JOIN_TAB *tab;
DBUG_ENTER("create_sort_index");
if (join->tables == join->const_tables)
DBUG_RETURN(0); // One row, no need to sort
tab= join->join_tab + join->const_tables;
table= tab->table;
select= tab->select;
if (test_if_skip_sort_order(tab,order,select_limit,0))
DBUG_RETURN(0);
if (!(sortorder=make_unireg_sortorder(order,&length)))
goto err; /* purecov: inspected */
/* It's not fatal if the following alloc fails */
table->sort.io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
MYF(MY_WME | MY_ZEROFILL));
table->status=0; // May be wrong if quick_select
// If table has a range, move it to select
if (select && !select->quick && tab->ref.key >= 0)
{
if (tab->quick)
{
select->quick=tab->quick;
tab->quick=0;
/* We can only use 'Only index' if quick key is same as ref_key */
if (table->key_read && (uint) tab->ref.key != select->quick->index)
{
table->key_read=0;
table->file->extra(HA_EXTRA_NO_KEYREAD);
}
}
else
{
/*
We have a ref on a const; Change this to a range that filesort
can use.
For impossible ranges (like when doing a lookup on NULL on a NOT NULL
field, quick will contain an empty record set.
*/
if (!(select->quick= (tab->type == JT_FT ?
new FT_SELECT(thd, table, tab->ref.key) :
get_quick_select_for_ref(thd, table, &tab->ref))))
goto err;
}
}
if (table->tmp_table)
table->file->info(HA_STATUS_VARIABLE); // Get record count
table->sort.found_records=filesort(thd, table,sortorder, length,
select, filesort_limit, &examined_rows);
tab->records= table->sort.found_records; // For SQL_CALC_ROWS
if (select)
{
select->cleanup(); // filesort did select
tab->select= 0;
}
tab->select_cond=0;
tab->type=JT_ALL; // Read with normal read_record
tab->read_first_record= join_init_read_record;
tab->join->examined_rows+=examined_rows;
if (table->key_read) // Restore if we used indexes
{
table->key_read=0;
table->file->extra(HA_EXTRA_NO_KEYREAD);
}
DBUG_RETURN(table->sort.found_records == HA_POS_ERROR);
err:
DBUG_RETURN(-1);
}
/*
Add the HAVING criteria to table->select
*/
#ifdef NOT_YET
static bool fix_having(JOIN *join, Item **having)
{
(*having)->update_used_tables(); // Some tables may have been const
JOIN_TAB *table=&join->join_tab[join->const_tables];
table_map used_tables= join->const_table_map | table->table->map;
DBUG_EXECUTE("where",print_where(*having,"having"););
Item* sort_table_cond=make_cond_for_table(*having,used_tables,used_tables);
if (sort_table_cond)
{
if (!table->select)
if (!(table->select=new SQL_SELECT))
return 1;
if (!table->select->cond)
table->select->cond=sort_table_cond;
else // This should never happen
if (!(table->select->cond= new Item_cond_and(table->select->cond,
sort_table_cond)) ||
table->select->cond->fix_fields(join->thd, join->tables_list,
&table->select->cond))
return 1;
table->select_cond=table->select->cond;
table->select_cond->top_level_item();
DBUG_EXECUTE("where",print_where(table->select_cond,
"select and having"););
*having=make_cond_for_table(*having,~ (table_map) 0,~used_tables);
DBUG_EXECUTE("where",print_where(*having,"having after make_cond"););
}
return 0;
}
#endif
/*****************************************************************************
Remove duplicates from tmp table
This should be recoded to add a unique index to the table and remove
duplicates
Table is a locked single thread table
fields is the number of fields to check (from the end)
*****************************************************************************/
static bool compare_record(TABLE *table, Field **ptr)
{
for (; *ptr ; ptr++)
{
if ((*ptr)->cmp_offset(table->rec_buff_length))
return 1;
}
return 0;
}
static bool copy_blobs(Field **ptr)
{
for (; *ptr ; ptr++)
{
if ((*ptr)->flags & BLOB_FLAG)
if (((Field_blob *) (*ptr))->copy())
return 1; // Error
}
return 0;
}
static void free_blobs(Field **ptr)
{
for (; *ptr ; ptr++)
{
if ((*ptr)->flags & BLOB_FLAG)
((Field_blob *) (*ptr))->free();
}
}
static int
remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having)
{
int error;
ulong reclength,offset;
uint field_count;
THD *thd= join->thd;
DBUG_ENTER("remove_duplicates");
entry->reginfo.lock_type=TL_WRITE;
/* Calculate how many saved fields there is in list */
field_count=0;
List_iterator<Item> it(fields);
Item *item;
while ((item=it++))
{
if (item->get_tmp_table_field() && ! item->const_item())
field_count++;
}
if (!field_count && !(join->select_options & OPTION_FOUND_ROWS))
{ // only const items with no OPTION_FOUND_ROWS
join->unit->select_limit_cnt= 1; // Only send first row
DBUG_RETURN(0);
}
Field **first_field=entry->field+entry->fields - field_count;
offset= field_count ?
entry->field[entry->fields - field_count]->offset() : 0;
reclength=entry->reclength-offset;
free_io_cache(entry); // Safety
entry->file->info(HA_STATUS_VARIABLE);
if (entry->db_type == DB_TYPE_HEAP ||
(!entry->blob_fields &&
((ALIGN_SIZE(reclength) + HASH_OVERHEAD) * entry->file->records <
thd->variables.sortbuff_size)))
error=remove_dup_with_hash_index(join->thd, entry,
field_count, first_field,
reclength, having);
else
error=remove_dup_with_compare(join->thd, entry, first_field, offset,
having);
free_blobs(first_field);
DBUG_RETURN(error);
}
static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
ulong offset, Item *having)
{
handler *file=table->file;
char *org_record,*new_record;
byte *record;
int error;
ulong reclength=table->reclength-offset;
DBUG_ENTER("remove_dup_with_compare");
org_record=(char*) (record=table->record[0])+offset;
new_record=(char*) table->record[1]+offset;
file->ha_rnd_init(1);
error=file->rnd_next(record);
for (;;)
{
if (thd->killed)
{
my_error(ER_SERVER_SHUTDOWN,MYF(0));
error=0;
goto err;
}
if (error)
{
if (error == HA_ERR_RECORD_DELETED)
continue;
if (error == HA_ERR_END_OF_FILE)
break;
goto err;
}
if (having && !having->val_int())
{
if ((error=file->delete_row(record)))
goto err;
error=file->rnd_next(record);
continue;
}
if (copy_blobs(first_field))
{
my_error(ER_OUTOFMEMORY,MYF(0));
error=0;
goto err;
}
memcpy(new_record,org_record,reclength);
/* Read through rest of file and mark duplicated rows deleted */
bool found=0;
for (;;)
{
if ((error=file->rnd_next(record)))
{
if (error == HA_ERR_RECORD_DELETED)
continue;
if (error == HA_ERR_END_OF_FILE)
break;
goto err;
}
if (compare_record(table, first_field) == 0)
{
if ((error=file->delete_row(record)))
goto err;
}
else if (!found)
{
found=1;
file->position(record); // Remember position
}
}
if (!found)
break; // End of file
/* Restart search on next row */
error=file->restart_rnd_next(record,file->ref);
}
file->extra(HA_EXTRA_NO_CACHE);
DBUG_RETURN(0);
err:
file->extra(HA_EXTRA_NO_CACHE);
if (error)
file->print_error(error,MYF(0));
DBUG_RETURN(1);
}
/*
Generate a hash index for each row to quickly find duplicate rows
Note that this will not work on tables with blobs!
*/
static int remove_dup_with_hash_index(THD *thd, TABLE *table,
uint field_count,
Field **first_field,
ulong key_length,
Item *having)
{
byte *key_buffer, *key_pos, *record=table->record[0];
int error;
handler *file= table->file;
ulong extra_length= ALIGN_SIZE(key_length)-key_length;
uint *field_lengths,*field_length;
HASH hash;
DBUG_ENTER("remove_dup_with_hash_index");
if (!my_multi_malloc(MYF(MY_WME),
&key_buffer,
(uint) ((key_length + extra_length) *
(long) file->records),
&field_lengths,
(uint) (field_count*sizeof(*field_lengths)),
NullS))
DBUG_RETURN(1);
{
Field **ptr;
ulong total_length= 0;
for (ptr= first_field, field_length=field_lengths ; *ptr ; ptr++)
{
uint length= (*ptr)->pack_length();
(*field_length++)= length;
total_length+= length;
}
DBUG_PRINT("info",("field_count: %u key_length: %lu total_length: %lu",
field_count, key_length, total_length));
DBUG_ASSERT(total_length <= key_length);
key_length= total_length;
extra_length= ALIGN_SIZE(key_length)-key_length;
}
if (hash_init(&hash, &my_charset_bin, (uint) file->records, 0,
key_length, (hash_get_key) 0, 0, 0))
{
my_free((char*) key_buffer,MYF(0));
DBUG_RETURN(1);
}
file->ha_rnd_init(1);
key_pos=key_buffer;
for (;;)
{
byte *org_key_pos;
if (thd->killed)
{
my_error(ER_SERVER_SHUTDOWN,MYF(0));
error=0;
goto err;
}
if ((error=file->rnd_next(record)))
{
if (error == HA_ERR_RECORD_DELETED)
continue;
if (error == HA_ERR_END_OF_FILE)
break;
goto err;
}
if (having && !having->val_int())
{
if ((error=file->delete_row(record)))
goto err;
continue;
}
/* copy fields to key buffer */
org_key_pos= key_pos;
field_length=field_lengths;
for (Field **ptr= first_field ; *ptr ; ptr++)
{
(*ptr)->sort_string((char*) key_pos,*field_length);
key_pos+= *field_length++;
}
/* Check if it exists before */
if (hash_search(&hash, org_key_pos, key_length))
{
/* Duplicated found ; Remove the row */
if ((error=file->delete_row(record)))
goto err;
}
else
(void) my_hash_insert(&hash, org_key_pos);
key_pos+=extra_length;
}
my_free((char*) key_buffer,MYF(0));
hash_free(&hash);
file->extra(HA_EXTRA_NO_CACHE);
(void) file->ha_rnd_end();
DBUG_RETURN(0);
err:
my_free((char*) key_buffer,MYF(0));
hash_free(&hash);
file->extra(HA_EXTRA_NO_CACHE);
(void) file->ha_rnd_end();
if (error)
file->print_error(error,MYF(0));
DBUG_RETURN(1);
}
SORT_FIELD *make_unireg_sortorder(ORDER *order, uint *length)
{
uint count;
SORT_FIELD *sort,*pos;
DBUG_ENTER("make_unireg_sortorder");
count=0;
for (ORDER *tmp = order; tmp; tmp=tmp->next)
count++;
pos=sort=(SORT_FIELD*) sql_alloc(sizeof(SORT_FIELD)*(count+1));
if (!pos)
return 0;
for (;order;order=order->next,pos++)
{
pos->field=0; pos->item=0;
if (order->item[0]->type() == Item::FIELD_ITEM)
pos->field= ((Item_field*) (*order->item))->field;
else if (order->item[0]->type() == Item::SUM_FUNC_ITEM &&
!order->item[0]->const_item())
pos->field= ((Item_sum*) order->item[0])->get_tmp_table_field();
else if (order->item[0]->type() == Item::COPY_STR_ITEM)
{ // Blob patch
pos->item= ((Item_copy_string*) (*order->item))->item;
}
else
pos->item= *order->item;
pos->reverse=! order->asc;
}
*length=count;
DBUG_RETURN(sort);
}
/*****************************************************************************
Fill join cache with packed records
Records are stored in tab->cache.buffer and last record in
last record is stored with pointers to blobs to support very big
records
******************************************************************************/
static int
join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count)
{
reg1 uint i;
uint length,blobs,size;
CACHE_FIELD *copy,**blob_ptr;
JOIN_CACHE *cache;
JOIN_TAB *join_tab;
DBUG_ENTER("join_init_cache");
cache= &tables[table_count].cache;
cache->fields=blobs=0;
join_tab=tables;
for (i=0 ; i < table_count ; i++,join_tab++)
{
if (!join_tab->used_fieldlength) /* Not calced yet */
calc_used_field_length(thd, join_tab);
cache->fields+=join_tab->used_fields;
blobs+=join_tab->used_blobs;
}
if (!(cache->field=(CACHE_FIELD*)
sql_alloc(sizeof(CACHE_FIELD)*(cache->fields+table_count*2)+(blobs+1)*
sizeof(CACHE_FIELD*))))
{
my_free((gptr) cache->buff,MYF(0)); /* purecov: inspected */
cache->buff=0; /* purecov: inspected */
DBUG_RETURN(1); /* purecov: inspected */
}
copy=cache->field;
blob_ptr=cache->blob_ptr=(CACHE_FIELD**)
(cache->field+cache->fields+table_count*2);
length=0;
for (i=0 ; i < table_count ; i++)
{
uint null_fields=0,used_fields;
Field **f_ptr,*field;
for (f_ptr=tables[i].table->field,used_fields=tables[i].used_fields ;
used_fields ;
f_ptr++)
{
field= *f_ptr;
if (field->query_id == thd->query_id)
{
used_fields--;
length+=field->fill_cache_field(copy);
if (copy->blob_field)
(*blob_ptr++)=copy;
if (field->maybe_null())
null_fields++;
copy++;
}
}
/* Copy null bits from table */
if (null_fields && tables[i].table->null_fields)
{ /* must copy null bits */
copy->str=(char*) tables[i].table->null_flags;
copy->length=tables[i].table->null_bytes;
copy->strip=0;
copy->blob_field=0;
length+=copy->length;
copy++;
cache->fields++;
}
/* If outer join table, copy null_row flag */
if (tables[i].table->maybe_null)
{
copy->str= (char*) &tables[i].table->null_row;
copy->length=sizeof(tables[i].table->null_row);
copy->strip=0;
copy->blob_field=0;
length+=copy->length;
copy++;
cache->fields++;
}
}
cache->length=length+blobs*sizeof(char*);
cache->blobs=blobs;
*blob_ptr=0; /* End sequentel */
size=max(thd->variables.join_buff_size, cache->length);
if (!(cache->buff=(uchar*) my_malloc(size,MYF(0))))
DBUG_RETURN(1); /* Don't use cache */ /* purecov: inspected */
cache->end=cache->buff+size;
reset_cache_write(cache);
DBUG_RETURN(0);
}
static ulong
used_blob_length(CACHE_FIELD **ptr)
{
uint length,blob_length;
for (length=0 ; *ptr ; ptr++)
{
(*ptr)->blob_length=blob_length=(*ptr)->blob_field->get_length();
length+=blob_length;
(*ptr)->blob_field->get_ptr(&(*ptr)->str);
}
return length;
}
static bool
store_record_in_cache(JOIN_CACHE *cache)
{
uint length;
uchar *pos;
CACHE_FIELD *copy,*end_field;
bool last_record;
pos=cache->pos;
end_field=cache->field+cache->fields;
length=cache->length;
if (cache->blobs)
length+=used_blob_length(cache->blob_ptr);
if ((last_record=(length+cache->length > (uint) (cache->end - pos))))
cache->ptr_record=cache->records;
/*
There is room in cache. Put record there
*/
cache->records++;
for (copy=cache->field ; copy < end_field; copy++)
{
if (copy->blob_field)
{
if (last_record)
{
copy->blob_field->get_image((char*) pos,copy->length+sizeof(char*),
copy->blob_field->charset());
pos+=copy->length+sizeof(char*);
}
else
{
copy->blob_field->get_image((char*) pos,copy->length, // blob length
copy->blob_field->charset());
memcpy(pos+copy->length,copy->str,copy->blob_length); // Blob data
pos+=copy->length+copy->blob_length;
}
}
else
{
if (copy->strip)
{
char *str,*end;
for (str=copy->str,end= str+copy->length;
end > str && end[-1] == ' ' ;
end--) ;
length=(uint) (end-str);
memcpy(pos+2, str, length);
int2store(pos, length);
pos+= length+2;
}
else
{
memcpy(pos,copy->str,copy->length);
pos+=copy->length;
}
}
}
cache->pos=pos;
return last_record || (uint) (cache->end -pos) < cache->length;
}
static void
reset_cache_read(JOIN_CACHE *cache)
{
cache->record_nr=0;
cache->pos=cache->buff;
}
static void reset_cache_write(JOIN_CACHE *cache)
{
reset_cache_read(cache);
cache->records= 0;
cache->ptr_record= (uint) ~0;
}
static void
read_cached_record(JOIN_TAB *tab)
{
uchar *pos;
uint length;
bool last_record;
CACHE_FIELD *copy,*end_field;
last_record=tab->cache.record_nr++ == tab->cache.ptr_record;
pos=tab->cache.pos;
for (copy=tab->cache.field,end_field=copy+tab->cache.fields ;
copy < end_field;
copy++)
{
if (copy->blob_field)
{
if (last_record)
{
copy->blob_field->set_image((char*) pos,copy->length+sizeof(char*),
copy->blob_field->charset());
pos+=copy->length+sizeof(char*);
}
else
{
copy->blob_field->set_ptr((char*) pos,(char*) pos+copy->length);
pos+=copy->length+copy->blob_field->get_length();
}
}
else
{
if (copy->strip)
{
length= uint2korr(pos);
memcpy(copy->str, pos+2, length);
memset(copy->str+length, ' ', copy->length-length);
pos+= 2 + length;
}
else
{
memcpy(copy->str,pos,copy->length);
pos+=copy->length;
}
}
}
tab->cache.pos=pos;
return;
}
static bool
cmp_buffer_with_ref(JOIN_TAB *tab)
{
bool diff;
if (!(diff=tab->ref.key_err))
{
memcpy(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length);
}
if ((tab->ref.key_err= cp_buffer_from_ref(tab->join->thd, &tab->ref)) ||
diff)
return 1;
return memcmp(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length)
!= 0;
}
bool
cp_buffer_from_ref(THD *thd, TABLE_REF *ref)
{
enum enum_check_fields save_count_cuted_fields= thd->count_cuted_fields;
thd->count_cuted_fields= CHECK_FIELD_IGNORE;
for (store_key **copy=ref->key_copy ; *copy ; copy++)
{
if ((*copy)->copy() & 1)
{
thd->count_cuted_fields= save_count_cuted_fields;
return 1; // Something went wrong
}
}
thd->count_cuted_fields= save_count_cuted_fields;
return 0;
}
/*****************************************************************************
Group and order functions
*****************************************************************************/
/*
Find order/group item in requested columns and change the item to point at
it. If item doesn't exists, add it first in the field list
Return 0 if ok.
*/
static int
find_order_in_list(THD *thd, Item **ref_pointer_array,
TABLE_LIST *tables,ORDER *order, List<Item> &fields,
List<Item> &all_fields)
{
Item *it= *order->item;
if (it->type() == Item::INT_ITEM)
{ /* Order by position */
uint count= (uint) it->val_int();
if (!count || count > fields.elements)
{
my_printf_error(ER_BAD_FIELD_ERROR,ER(ER_BAD_FIELD_ERROR),
MYF(0), it->full_name(), thd->where);
return 1;
}
order->item= ref_pointer_array + count-1;
order->in_field_list= 1;
return 0;
}
uint counter;
bool unaliased;
Item **item= find_item_in_list(it, fields, &counter,
REPORT_EXCEPT_NOT_FOUND, &unaliased);
if (!item)
return 1;
if (item != (Item **)not_found_item)
{
/*
If we have found field not by its alias in select list but by its
original field name, we should additionaly check if we have conflict
for this name (in case if we would perform lookup in all tables).
*/
if (unaliased && !it->fixed && it->fix_fields(thd, tables, order->item))
return 1;
order->item= ref_pointer_array + counter;
order->in_field_list=1;
return 0;
}
order->in_field_list=0;
/*
We check it->fixed because Item_func_group_concat can put
arguments for which fix_fields already was called.
'it' reassigned in if condition because fix_field can change it.
*/
thd->lex->current_select->is_item_list_lookup= 1;
if (!it->fixed &&
(it->fix_fields(thd, tables, order->item) ||
(it= *order->item)->check_cols(1) ||
thd->is_fatal_error))
{
thd->lex->current_select->is_item_list_lookup= 0;
return 1; // Wrong field
}
thd->lex->current_select->is_item_list_lookup= 0;
uint el= all_fields.elements;
all_fields.push_front(it); // Add new field to field list
ref_pointer_array[el]= it;
order->item= ref_pointer_array + el;
return 0;
}
/*
Change order to point at item in select list. If item isn't a number
and doesn't exits in the select list, add it the the field list.
*/
int setup_order(THD *thd, Item **ref_pointer_array, TABLE_LIST *tables,
List<Item> &fields, List<Item> &all_fields, ORDER *order)
{
thd->where="order clause";
for (; order; order=order->next)
{
if (find_order_in_list(thd, ref_pointer_array, tables, order, fields,
all_fields))
return 1;
}
return 0;
}
/*
Intitialize the GROUP BY list.
SYNOPSIS
setup_group()
thd Thread handler
ref_pointer_array We store references to all fields that was not in
'fields' here.
fields All fields in the select part. Any item in 'order'
that is part of these list is replaced by a pointer
to this fields.
all_fields Total list of all unique fields used by the select.
All items in 'order' that was not part of fields will
be added first to this list.
order The fields we should do GROUP BY on.
hidden_group_fields Pointer to flag that is set to 1 if we added any fields
to all_fields.
RETURN
0 ok
1 error (probably out of memory)
*/
int
setup_group(THD *thd, Item **ref_pointer_array, TABLE_LIST *tables,
List<Item> &fields, List<Item> &all_fields, ORDER *order,
bool *hidden_group_fields)
{
*hidden_group_fields=0;
if (!order)
return 0; /* Everything is ok */
if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
{
Item *item;
List_iterator<Item> li(fields);
while ((item=li++))
item->marker=0; /* Marker that field is not used */
}
uint org_fields=all_fields.elements;
thd->where="group statement";
for (; order; order=order->next)
{
if (find_order_in_list(thd, ref_pointer_array, tables, order, fields,
all_fields))
return 1;
(*order->item)->marker=1; /* Mark found */
if ((*order->item)->with_sum_func)
{
my_printf_error(ER_WRONG_GROUP_FIELD, ER(ER_WRONG_GROUP_FIELD),MYF(0),
(*order->item)->full_name());
return 1;
}
}
if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
{
/* Don't allow one to use fields that is not used in GROUP BY */
Item *item;
List_iterator<Item> li(fields);
while ((item=li++))
{
if (item->type() != Item::SUM_FUNC_ITEM && !item->marker &&
!item->const_item())
{
my_printf_error(ER_WRONG_FIELD_WITH_GROUP,
ER(ER_WRONG_FIELD_WITH_GROUP),
MYF(0),item->full_name());
return 1;
}
}
}
if (org_fields != all_fields.elements)
*hidden_group_fields=1; // group fields is not used
return 0;
}
/*
Add fields with aren't used at start of field list. Return FALSE if ok
*/
static bool
setup_new_fields(THD *thd,TABLE_LIST *tables,List<Item> &fields,
List<Item> &all_fields, ORDER *new_field)
{
Item **item;
DBUG_ENTER("setup_new_fields");
thd->set_query_id=1; // Not really needed, but...
uint counter;
bool not_used;
for (; new_field ; new_field= new_field->next)
{
if ((item= find_item_in_list(*new_field->item, fields, &counter,
IGNORE_ERRORS, &not_used)))
new_field->item=item; /* Change to shared Item */
else
{
thd->where="procedure list";
if ((*new_field->item)->fix_fields(thd, tables, new_field->item))
DBUG_RETURN(1); /* purecov: inspected */
all_fields.push_front(*new_field->item);
new_field->item=all_fields.head_ref();
}
}
DBUG_RETURN(0);
}
/*
Create a group by that consist of all non const fields. Try to use
the fields in the order given by 'order' to allow one to optimize
away 'order by'.
*/
static ORDER *
create_distinct_group(THD *thd, Item **ref_pointer_array,
ORDER *order_list, List<Item> &fields,
bool *all_order_by_fields_used)
{
List_iterator<Item> li(fields);
Item *item;
ORDER *order,*group,**prev;
uint index= 0;
*all_order_by_fields_used= 1;
while ((item=li++))
item->marker=0; /* Marker that field is not used */
prev= &group; group=0;
for (order=order_list ; order; order=order->next)
{
if (order->in_field_list)
{
ORDER *ord=(ORDER*) thd->memdup((char*) order,sizeof(ORDER));
if (!ord)
return 0;
*prev=ord;
prev= &ord->next;
(*ord->item)->marker=1;
}
else
*all_order_by_fields_used= 0;
}
li.rewind();
while ((item=li++))
{
if (!item->const_item() && !item->with_sum_func && !item->marker)
{
ORDER *ord=(ORDER*) thd->calloc(sizeof(ORDER));
if (!ord)
return 0;
/*
We have here only field_list (not all_field_list), so we can use
simple indexing of ref_pointer_array (order in the array and in the
list are same)
*/
ord->item= ref_pointer_array + index;
ord->asc=1;
*prev=ord;
prev= &ord->next;
}
index++;
}
*prev=0;
return group;
}
/*****************************************************************************
Update join with count of the different type of fields
*****************************************************************************/
void
count_field_types(TMP_TABLE_PARAM *param, List<Item> &fields,
bool reset_with_sum_func)
{
List_iterator<Item> li(fields);
Item *field;
param->field_count=param->sum_func_count=param->func_count=
param->hidden_field_count=0;
param->quick_group=1;
while ((field=li++))
{
Item::Type type=field->type();
if (type == Item::FIELD_ITEM)
param->field_count++;
else if (type == Item::SUM_FUNC_ITEM)
{
if (! field->const_item())
{
Item_sum *sum_item=(Item_sum*) field;
if (!sum_item->quick_group)
param->quick_group=0; // UDF SUM function
param->sum_func_count++;
for (uint i=0 ; i < sum_item->arg_count ; i++)
{
if (sum_item->args[0]->type() == Item::FIELD_ITEM)
param->field_count++;
else
param->func_count++;
}
}
}
else
{
param->func_count++;
if (reset_with_sum_func)
field->with_sum_func=0;
}
}
}
/*
Return 1 if second is a subpart of first argument
If first parts has different direction, change it to second part
(group is sorted like order)
*/
static bool
test_if_subpart(ORDER *a,ORDER *b)
{
for (; a && b; a=a->next,b=b->next)
{
if ((*a->item)->eq(*b->item,1))
a->asc=b->asc;
else
return 0;
}
return test(!b);
}
/*
Return table number if there is only one table in sort order
and group and order is compatible
else return 0;
*/
static TABLE *
get_sort_by_table(ORDER *a,ORDER *b,TABLE_LIST *tables)
{
table_map map= (table_map) 0;
DBUG_ENTER("get_sort_by_table");
if (!a)
a=b; // Only one need to be given
else if (!b)
b=a;
for (; a && b; a=a->next,b=b->next)
{
if (!(*a->item)->eq(*b->item,1))
DBUG_RETURN(0);
map|=a->item[0]->used_tables();
}
if (!map || (map & (RAND_TABLE_BIT | OUTER_REF_TABLE_BIT)))
DBUG_RETURN(0);
for (; !(map & tables->table->map) ; tables=tables->next) ;
if (map != tables->table->map)
DBUG_RETURN(0); // More than one table
DBUG_PRINT("exit",("sort by table: %d",tables->table->tablenr));
DBUG_RETURN(tables->table);
}
/* calc how big buffer we need for comparing group entries */
static void
calc_group_buffer(JOIN *join,ORDER *group)
{
uint key_length=0, parts=0, null_parts=0;
if (group)
join->group= 1;
for (; group ; group=group->next)
{
Field *field=(*group->item)->get_tmp_table_field();
if (field)
{
if (field->type() == FIELD_TYPE_BLOB)
key_length+=MAX_BLOB_WIDTH; // Can't be used as a key
else
key_length+=field->pack_length();
}
else if ((*group->item)->result_type() == REAL_RESULT)
key_length+=sizeof(double);
else if ((*group->item)->result_type() == INT_RESULT)
key_length+=sizeof(longlong);
else
key_length+=(*group->item)->max_length;
parts++;
if ((*group->item)->maybe_null)
null_parts++;
}
join->tmp_table_param.group_length=key_length+null_parts;
join->tmp_table_param.group_parts=parts;
join->tmp_table_param.group_null_parts=null_parts;
}
/*
allocate group fields or take prepared (cached)
SYNOPSIS
make_group_fields()
main_join - join of current select
curr_join - current join (join of current select or temporary copy of it)
RETURN
0 - ok
1 - failed
*/
static bool
make_group_fields(JOIN *main_join, JOIN *curr_join)
{
if (main_join->group_fields_cache.elements)
{
curr_join->group_fields= main_join->group_fields_cache;
curr_join->sort_and_group= 1;
}
else
{
if (alloc_group_fields(curr_join, curr_join->group_list))
return (1);
main_join->group_fields_cache= curr_join->group_fields;
}
return (0);
}
/*
Get a list of buffers for saveing last group
Groups are saved in reverse order for easyer check loop
*/
static bool
alloc_group_fields(JOIN *join,ORDER *group)
{
if (group)
{
for (; group ; group=group->next)
{
Item_buff *tmp=new_Item_buff(join->thd, *group->item);
if (!tmp || join->group_fields.push_front(tmp))
return TRUE;
}
}
join->sort_and_group=1; /* Mark for do_select */
return FALSE;
}
static int
test_if_group_changed(List<Item_buff> &list)
{
DBUG_ENTER("test_if_group_changed");
List_iterator<Item_buff> li(list);
int idx= -1,i;
Item_buff *buff;
for (i=(int) list.elements-1 ; (buff=li++) ; i--)
{
if (buff->cmp())
idx=i;
}
DBUG_PRINT("info", ("idx: %d", idx));
DBUG_RETURN(idx);
}
/*
Setup copy_fields to save fields at start of new group
setup_copy_fields()
thd - THD pointer
param - temporary table parameters
ref_pointer_array - array of pointers to top elements of filed list
res_selected_fields - new list of items of select item list
res_all_fields - new list of all items
elements - number of elements in select item list
all_fields - all fields list
DESCRIPTION
Setup copy_fields to save fields at start of new group
Only FIELD_ITEM:s and FUNC_ITEM:s needs to be saved between groups.
Change old item_field to use a new field with points at saved fieldvalue
This function is only called before use of send_fields
RETURN
0 - ok
!=0 - error
*/
bool
setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
Item **ref_pointer_array,
List<Item> &res_selected_fields, List<Item> &res_all_fields,
uint elements, List<Item> &all_fields)
{
Item *pos;
List_iterator_fast<Item> li(all_fields);
Copy_field *copy= NULL;
res_selected_fields.empty();
res_all_fields.empty();
List_iterator_fast<Item> itr(res_all_fields);
List<Item> extra_funcs;
uint i, border= all_fields.elements - elements;
DBUG_ENTER("setup_copy_fields");
if (param->field_count &&
!(copy=param->copy_field= new Copy_field[param->field_count]))
goto err2;
param->copy_funcs.empty();
for (i= 0; (pos= li++); i++)
{
Field *field;
char *tmp;
if (pos->type() == Item::FIELD_ITEM)
{
Item_field *item;
if (!(item= new Item_field(thd, ((Item_field*) pos))))
goto err;
pos= item;
if (item->field->flags & BLOB_FLAG)
{
if (!(pos= new Item_copy_string(pos)))
goto err;
/*
Item_copy_string::copy for function can call
Item_copy_string::val_int for blob via Item_ref.
But if Item_copy_string::copy for blob isn't called before,
it's value will be wrong
so let's insert Item_copy_string for blobs in the beginning of
copy_funcs
(to see full test case look at having.test, BUG #4358)
*/
if (param->copy_funcs.push_front(pos))
goto err;
}
else
{
/*
set up save buffer and change result_field to point at
saved value
*/
field= item->field;
item->result_field=field->new_field(thd->mem_root,field->table);
/*
We need to allocate one extra byte for null handling and
another extra byte to not get warnings from purify in
Field_string::val_int
*/
tmp= (char*) sql_alloc(field->pack_length()+2);
if (!tmp)
goto err;
copy->set(tmp, item->result_field);
item->result_field->move_field(copy->to_ptr,copy->to_null_ptr,1);
#ifdef HAVE_purify
copy->to_ptr[copy->from_length]= 0;
#endif
copy++;
}
}
else if ((pos->type() == Item::FUNC_ITEM ||
pos->type() == Item::SUBSELECT_ITEM ||
pos->type() == Item::CACHE_ITEM ||
pos->type() == Item::COND_ITEM) &&
!pos->with_sum_func)
{ // Save for send fields
/* TODO:
In most cases this result will be sent to the user.
This should be changed to use copy_int or copy_real depending
on how the value is to be used: In some cases this may be an
argument in a group function, like: IF(ISNULL(col),0,COUNT(*))
*/
if (!(pos=new Item_copy_string(pos)))
goto err;
if (i < border) // HAVING, ORDER and GROUP BY
{
if (extra_funcs.push_back(pos))
goto err;
}
else if (param->copy_funcs.push_back(pos))
goto err;
}
res_all_fields.push_back(pos);
ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
pos;
}
param->copy_field_end= copy;
for (i= 0; i < border; i++)
itr++;
itr.sublist(res_selected_fields, elements);
/*
Put elements from HAVING, ORDER BY and GROUP BY last to ensure that any
reference used in these will resolve to a item that is already calculated
*/
param->copy_funcs.concat(&extra_funcs);
DBUG_RETURN(0);
err:
if (copy)
delete [] param->copy_field;
param->copy_field=0;
err2:
DBUG_RETURN(TRUE);
}
/*
Make a copy of all simple SELECT'ed items
This is done at the start of a new group so that we can retrieve
these later when the group changes.
*/
void
copy_fields(TMP_TABLE_PARAM *param)
{
Copy_field *ptr=param->copy_field;
Copy_field *end=param->copy_field_end;
for (; ptr != end; ptr++)
(*ptr->do_copy)(ptr);
List_iterator_fast<Item> it(param->copy_funcs);
Item_copy_string *item;
while ((item = (Item_copy_string*) it++))
item->copy();
}
/*
Make an array of pointers to sum_functions to speed up sum_func calculation
SYNOPSIS
alloc_func_list()
RETURN
0 ok
1 Error
*/
bool JOIN::alloc_func_list()
{
uint func_count, group_parts;
DBUG_ENTER("alloc_func_list");
func_count= tmp_table_param.sum_func_count;
/*
If we are using rollup, we need a copy of the summary functions for
each level
*/
if (rollup.state != ROLLUP::STATE_NONE)
func_count*= (send_group_parts+1);
group_parts= send_group_parts;
/*
If distinct, reserve memory for possible
disctinct->group_by optimization
*/
if (select_distinct)
group_parts+= fields_list.elements;
/* This must use calloc() as rollup_make_fields depends on this */
sum_funcs= (Item_sum**) thd->calloc(sizeof(Item_sum**) * (func_count+1) +
sizeof(Item_sum***) * (group_parts+1));
sum_funcs_end= (Item_sum***) (sum_funcs+func_count+1);
DBUG_RETURN(sum_funcs == 0);
}
/*
Initialize 'sum_funcs' array with all Item_sum objects
SYNOPSIS
make_sum_func_list()
field_list All items
send_fields Items in select list
before_group_by Set to 1 if this is called before GROUP BY handling
NOTES
Calls ::setup() for all item_sum objects in field_list
RETURN
0 ok
1 error
*/
bool JOIN::make_sum_func_list(List<Item> &field_list, List<Item> &send_fields,
bool before_group_by)
{
List_iterator_fast<Item> it(field_list);
Item_sum **func;
Item *item;
DBUG_ENTER("make_sum_func_list");
func= sum_funcs;
while ((item=it++))
{
if (item->type() == Item::SUM_FUNC_ITEM && !item->const_item())
{
*func++= (Item_sum*) item;
/* let COUNT(DISTINCT) create the temporary table */
if (((Item_sum*) item)->setup(thd))
DBUG_RETURN(TRUE);
}
}
if (before_group_by && rollup.state == ROLLUP::STATE_INITED)
{
rollup.state= ROLLUP::STATE_READY;
if (rollup_make_fields(field_list, send_fields, &func))
DBUG_RETURN(TRUE); // Should never happen
}
else if (rollup.state == ROLLUP::STATE_NONE)
{
for (uint i=0 ; i <= send_group_parts ;i++)
sum_funcs_end[i]= func;
}
else if (rollup.state == ROLLUP::STATE_READY)
DBUG_RETURN(FALSE); // Don't put end marker
*func=0; // End marker
DBUG_RETURN(FALSE);
}
/*
Change all funcs and sum_funcs to fields in tmp table, and create
new list of all items.
change_to_use_tmp_fields()
thd - THD pointer
ref_pointer_array - array of pointers to top elements of filed list
res_selected_fields - new list of items of select item list
res_all_fields - new list of all items
elements - number of elements in select item list
all_fields - all fields list
RETURN
0 - ok
!=0 - error
*/
static bool
change_to_use_tmp_fields(THD *thd, Item **ref_pointer_array,
List<Item> &res_selected_fields,
List<Item> &res_all_fields,
uint elements, List<Item> &all_fields)
{
List_iterator_fast<Item> it(all_fields);
Item *item_field,*item;
res_selected_fields.empty();
res_all_fields.empty();
uint i, border= all_fields.elements - elements;
for (i= 0; (item= it++); i++)
{
Field *field;
if (item->with_sum_func && item->type() != Item::SUM_FUNC_ITEM)
item_field= item;
else
{
if (item->type() == Item::FIELD_ITEM)
{
item_field= item->get_tmp_table_item(thd);
}
else if ((field= item->get_tmp_table_field()))
{
if (item->type() == Item::SUM_FUNC_ITEM && field->table->group)
item_field= ((Item_sum*) item)->result_item(field);
else
item_field= (Item*) new Item_field(field);
if (!item_field)
return TRUE; // Fatal error
item_field->name= item->name; /*lint -e613 */
#ifndef DBUG_OFF
if (_db_on_ && !item_field->name)
{
char buff[256];
String str(buff,sizeof(buff),&my_charset_bin);
str.length(0);
item->print(&str);
item_field->name= sql_strmake(str.ptr(),str.length());
}
#endif
}
else
item_field= item;
}
res_all_fields.push_back(item_field);
ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
item_field;
}
List_iterator_fast<Item> itr(res_all_fields);
for (i= 0; i < border; i++)
itr++;
itr.sublist(res_selected_fields, elements);
return FALSE;
}
/*
Change all sum_func refs to fields to point at fields in tmp table
Change all funcs to be fields in tmp table
change_refs_to_tmp_fields()
thd - THD pointer
ref_pointer_array - array of pointers to top elements of filed list
res_selected_fields - new list of items of select item list
res_all_fields - new list of all items
elements - number of elements in select item list
all_fields - all fields list
RETURN
0 ok
1 error
*/
static bool
change_refs_to_tmp_fields(THD *thd, Item **ref_pointer_array,
List<Item> &res_selected_fields,
List<Item> &res_all_fields, uint elements,
List<Item> &all_fields)
{
List_iterator_fast<Item> it(all_fields);
Item *item, *new_item;
res_selected_fields.empty();
res_all_fields.empty();
uint i, border= all_fields.elements - elements;
for (i= 0; (item= it++); i++)
{
res_all_fields.push_back(new_item= item->get_tmp_table_item(thd));
ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
new_item;
}
List_iterator_fast<Item> itr(res_all_fields);
for (i= 0; i < border; i++)
itr++;
itr.sublist(res_selected_fields, elements);
return thd->is_fatal_error;
}
/******************************************************************************
Code for calculating functions
******************************************************************************/
static void
init_tmptable_sum_functions(Item_sum **func_ptr)
{
Item_sum *func;
while ((func= *(func_ptr++)))
func->reset_field();
}
/* Update record 0 in tmp_table from record 1 */
static void
update_tmptable_sum_func(Item_sum **func_ptr,
TABLE *tmp_table __attribute__((unused)))
{
Item_sum *func;
while ((func= *(func_ptr++)))
func->update_field();
}
/* Copy result of sum functions to record in tmp_table */
static void
copy_sum_funcs(Item_sum **func_ptr, Item_sum **end_ptr)
{
for (; func_ptr != end_ptr ; func_ptr++)
(void) (*func_ptr)->save_in_result_field(1);
return;
}
static bool
init_sum_functions(Item_sum **func_ptr, Item_sum **end_ptr)
{
for (; func_ptr != end_ptr ;func_ptr++)
{
if ((*func_ptr)->reset())
return 1;
}
/* If rollup, calculate the upper sum levels */
for ( ; *func_ptr ; func_ptr++)
{
if ((*func_ptr)->add())
return 1;
}
return 0;
}
static bool
update_sum_func(Item_sum **func_ptr)
{
Item_sum *func;
for (; (func= (Item_sum*) *func_ptr) ; func_ptr++)
if (func->add())
return 1;
return 0;
}
/* Copy result of functions to record in tmp_table */
void
copy_funcs(Item **func_ptr)
{
Item *func;
for (; (func = *func_ptr) ; func_ptr++)
func->save_in_result_field(1);
}
/*
Create a condition for a const reference and add this to the
currenct select for the table
*/
static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab)
{
DBUG_ENTER("add_ref_to_table_cond");
if (!join_tab->ref.key_parts)
DBUG_RETURN(FALSE);
Item_cond_and *cond=new Item_cond_and();
TABLE *table=join_tab->table;
int error;
if (!cond)
DBUG_RETURN(TRUE);
for (uint i=0 ; i < join_tab->ref.key_parts ; i++)
{
Field *field=table->field[table->key_info[join_tab->ref.key].key_part[i].
fieldnr-1];
Item *value=join_tab->ref.items[i];
cond->add(new Item_func_equal(new Item_field(field), value));
}
if (thd->is_fatal_error)
DBUG_RETURN(TRUE);
if (!cond->fixed)
cond->fix_fields(thd,(TABLE_LIST *) 0, (Item**)&cond);
if (join_tab->select)
{
error=(int) cond->add(join_tab->select->cond);
join_tab->select_cond=join_tab->select->cond=cond;
}
else if ((join_tab->select=make_select(join_tab->table, 0, 0, cond,&error)))
join_tab->select_cond=cond;
DBUG_RETURN(error ? TRUE : FALSE);
}
/*
Free joins of subselect of this select.
free_underlaid_joins()
thd - THD pointer
select - pointer to st_select_lex which subselects joins we will free
*/
void free_underlaid_joins(THD *thd, SELECT_LEX *select)
{
for (SELECT_LEX_UNIT *unit= select->first_inner_unit();
unit;
unit= unit->next_unit())
unit->cleanup();
}
/****************************************************************************
ROLLUP handling
****************************************************************************/
/*
Replace occurences of group by fields in an expression by ref items
SYNOPSIS
change_group_ref()
thd reference to the context
expr expression to make replacement
group_list list of references to group by items
changed out: returns 1 if item contains a replaced field item
DESCRIPTION
The function replaces occurrences of group by fields in expr
by ref objects for these fields unless they are under aggregate
functions.
The function also corrects value of the the maybe_null attribute
for the items of all subexpressions containing group by fields.
IMPLEMENTATION
The function recursively traverses the tree of the expr expression,
looks for occurrences of the group by fields that are not under
aggregate functions and replaces them for the corresponding ref items.
NOTES
This substitution is needed GROUP BY queries with ROLLUP if
SELECT list contains expressions over group by attributes.
TODO: Some functions are not null-preserving. For those functions
updating of the maybe_null attribute is an overkill.
EXAMPLES
SELECT a+1 FROM t1 GROUP BY a WITH ROLLUP
SELECT SUM(a)+a FROM t1 GROUP BY a WITH ROLLUP
RETURN
0 if ok
1 on error
*/
static bool change_group_ref(THD *thd, Item_func *expr, ORDER *group_list,
bool *changed)
{
if (expr->arg_count)
{
Item **arg,**arg_end;
bool arg_changed= FALSE;
for (arg= expr->arguments(),
arg_end= expr->arguments()+expr->arg_count;
arg != arg_end; arg++)
{
Item *item= *arg;
if (item->type() == Item::FIELD_ITEM || item->type() == Item::REF_ITEM)
{
ORDER *group_tmp;
for (group_tmp= group_list; group_tmp; group_tmp= group_tmp->next)
{
if (item->eq(*group_tmp->item,0))
{
Item *new_item;
if(!(new_item= new Item_ref(group_tmp->item, 0, item->name)))
return 1; // fatal_error is set
thd->change_item_tree(arg, new_item);
arg_changed= TRUE;
}
}
}
else if (item->type() == Item::FUNC_ITEM)
{
if (change_group_ref(thd, (Item_func *) item, group_list, &arg_changed))
return 1;
}
}
if (arg_changed)
{
expr->maybe_null= 1;
*changed= TRUE;
}
}
return 0;
}
/* Allocate memory needed for other rollup functions */
bool JOIN::rollup_init()
{
uint i,j;
Item **ref_array;
tmp_table_param.quick_group= 0; // Can't create groups in tmp table
rollup.state= ROLLUP::STATE_INITED;
/*
Create pointers to the different sum function groups
These are updated by rollup_make_fields()
*/
tmp_table_param.group_parts= send_group_parts;
if (!(rollup.null_items= (Item_null_result**) thd->alloc((sizeof(Item*) +
sizeof(Item**) +
sizeof(List<Item>) +
ref_pointer_array_size)
* send_group_parts )))
return 1;
rollup.fields= (List<Item>*) (rollup.null_items + send_group_parts);
rollup.ref_pointer_arrays= (Item***) (rollup.fields + send_group_parts);
ref_array= (Item**) (rollup.ref_pointer_arrays+send_group_parts);
/*
Prepare space for field list for the different levels
These will be filled up in rollup_make_fields()
*/
for (i= 0 ; i < send_group_parts ; i++)
{
rollup.null_items[i]= new (thd->mem_root) Item_null_result();
List<Item> *rollup_fields= &rollup.fields[i];
rollup_fields->empty();
rollup.ref_pointer_arrays[i]= ref_array;
ref_array+= all_fields.elements;
}
for (i= 0 ; i < send_group_parts; i++)
{
for (j=0 ; j < fields_list.elements ; j++)
rollup.fields[i].push_back(rollup.null_items[i]);
}
List_iterator_fast<Item> it(all_fields);
Item *item;
while ((item= it++))
{
ORDER *group_tmp;
bool found_in_group= 0;
for (group_tmp= group_list; group_tmp; group_tmp= group_tmp->next)
{
if (*group_tmp->item == item)
{
item->maybe_null= 1;
found_in_group= 1;
}
}
if (item->type() == Item::FUNC_ITEM && !found_in_group)
{
bool changed= FALSE;
if (change_group_ref(thd, (Item_func *) item, group_list, &changed))
return 1;
/*
We have to prevent creation of a field in a temporary table for
an expression that contains GROUP BY attributes.
Marking the expression item as 'with_sum_func' will ensure this.
*/
if (changed)
item->with_sum_func= 1;
}
}
return 0;
}
/*
Fill up rollup structures with pointers to fields to use
SYNOPSIS
rollup_make_fields()
fields_arg List of all fields (hidden and real ones)
sel_fields Pointer to selected fields
func Store here a pointer to all fields
IMPLEMENTATION:
Creates copies of item_sum items for each sum level
RETURN
0 if ok
In this case func is pointing to next not used element.
1 on error
*/
bool JOIN::rollup_make_fields(List<Item> &fields_arg, List<Item> &sel_fields,
Item_sum ***func)
{
List_iterator_fast<Item> it(fields_arg);
Item *first_field= sel_fields.head();
uint level;
/*
Create field lists for the different levels
The idea here is to have a separate field list for each rollup level to
avoid all runtime checks of which columns should be NULL.
The list is stored in reverse order to get sum function in such an order
in func that it makes it easy to reset them with init_sum_functions()
Assuming: SELECT a, b, c SUM(b) FROM t1 GROUP BY a,b WITH ROLLUP
rollup.fields[0] will contain list where a,b,c is NULL
rollup.fields[1] will contain list where b,c is NULL
...
rollup.ref_pointer_array[#] points to fields for rollup.fields[#]
...
sum_funcs_end[0] points to all sum functions
sum_funcs_end[1] points to all sum functions, except grand totals
...
*/
for (level=0 ; level < send_group_parts ; level++)
{
uint i;
uint pos= send_group_parts - level -1;
bool real_fields= 0;
Item *item;
List_iterator<Item> new_it(rollup.fields[pos]);
Item **ref_array_start= rollup.ref_pointer_arrays[pos];
ORDER *start_group;
/* Point to first hidden field */
Item **ref_array= ref_array_start + fields_arg.elements-1;
/* Remember where the sum functions ends for the previous level */
sum_funcs_end[pos+1]= *func;
/* Find the start of the group for this level */
for (i= 0, start_group= group_list ;
i++ < pos ;
start_group= start_group->next)
;
it.rewind();
while ((item= it++))
{
if (item == first_field)
{
real_fields= 1; // End of hidden fields
ref_array= ref_array_start;
}
if (item->type() == Item::SUM_FUNC_ITEM && !item->const_item())
{
/*
This is a top level summary function that must be replaced with
a sum function that is reset for this level.
NOTE: This code creates an object which is not that nice in a
sub select. Fortunately it's not common to have rollup in
sub selects.
*/
item= item->copy_or_same(thd);
((Item_sum*) item)->make_unique();
if (((Item_sum*) item)->setup(thd))
return 1;
*(*func)= (Item_sum*) item;
(*func)++;
}
else
{
/* Check if this is something that is part of this group by */
ORDER *group_tmp;
for (group_tmp= start_group, i= pos ;
group_tmp ; group_tmp= group_tmp->next, i++)
{
if (*group_tmp->item == item)
{
/*
This is an element that is used by the GROUP BY and should be
set to NULL in this level
*/
Item_null_result *null_item;
item->maybe_null= 1; // Value will be null sometimes
null_item= rollup.null_items[i];
null_item->result_field= item->get_tmp_table_field();
item= null_item;
break;
}
}
}
*ref_array= item;
if (real_fields)
{
(void) new_it++; // Point to next item
new_it.replace(item); // Replace previous
ref_array++;
}
else
ref_array--;
}
}
sum_funcs_end[0]= *func; // Point to last function
return 0;
}
/*
Send all rollup levels higher than the current one to the client
SYNOPSIS:
rollup_send_data()
idx Level we are on:
0 = Total sum level
1 = First group changed (a)
2 = Second group changed (a,b)
SAMPLE
SELECT a, b, c SUM(b) FROM t1 GROUP BY a,b WITH ROLLUP
RETURN
0 ok
1 If send_data_failed()
*/
int JOIN::rollup_send_data(uint idx)
{
uint i;
for (i= send_group_parts ; i-- > idx ; )
{
/* Get reference pointers to sum functions in place */
memcpy((char*) ref_pointer_array,
(char*) rollup.ref_pointer_arrays[i],
ref_pointer_array_size);
if ((!having || having->val_int()))
{
if (send_records < unit->select_limit_cnt && do_send_rows &&
result->send_data(rollup.fields[i]))
return 1;
send_records++;
}
}
/* Restore ref_pointer_array */
set_items_ref_array(current_ref_pointer_array);
return 0;
}
/*
Write all rollup levels higher than the current one to a temp table
SYNOPSIS:
rollup_write_data()
idx Level we are on:
0 = Total sum level
1 = First group changed (a)
2 = Second group changed (a,b)
table reference to temp table
SAMPLE
SELECT a, b, SUM(c) FROM t1 GROUP BY a,b WITH ROLLUP
RETURN
0 ok
1 if write_data_failed()
*/
int JOIN::rollup_write_data(uint idx, TABLE *table)
{
uint i;
for (i= send_group_parts ; i-- > idx ; )
{
/* Get reference pointers to sum functions in place */
memcpy((char*) ref_pointer_array,
(char*) rollup.ref_pointer_arrays[i],
ref_pointer_array_size);
if ((!having || having->val_int()))
{
int error;
Item *item;
List_iterator_fast<Item> it(rollup.fields[i]);
while ((item= it++))
{
if (item->type() == Item::NULL_ITEM && item->is_result_field())
item->save_in_result_field(1);
}
copy_sum_funcs(sum_funcs_end[i+1], sum_funcs_end[i]);
if ((error= table->file->write_row(table->record[0])))
{
if (create_myisam_from_heap(thd, table, &tmp_table_param,
error, 0))
return 1;
}
}
}
/* Restore ref_pointer_array */
set_items_ref_array(current_ref_pointer_array);
return 0;
}
/*
clear results if there are not rows found for group
(end_send_group/end_write_group)
SYNOPSYS
JOIN::clear()
*/
void JOIN::clear()
{
clear_tables(this);
copy_fields(&tmp_table_param);
if (sum_funcs)
{
Item_sum *func, **func_ptr= sum_funcs;
while ((func= *(func_ptr++)))
func->clear();
}
}
/****************************************************************************
EXPLAIN handling
Send a description about what how the select will be done to stdout
****************************************************************************/
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
bool distinct,const char *message)
{
List<Item> field_list;
List<Item> item_list;
THD *thd=join->thd;
select_result *result=join->result;
Item *item_null= new Item_null();
CHARSET_INFO *cs= system_charset_info;
DBUG_ENTER("select_describe");
DBUG_PRINT("info", ("Select 0x%lx, type %s, message %s",
(ulong)join->select_lex, join->select_lex->type,
message ? message : "NULL"));
/* Don't log this into the slow query log */
thd->server_status&= ~(SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED);
join->unit->offset_limit_cnt= 0;
if (message)
{
item_list.push_back(new Item_int((int32)
join->select_lex->select_number));
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type), cs));
for (uint i=0 ; i < 7; i++)
item_list.push_back(item_null);
item_list.push_back(new Item_string(message,strlen(message),cs));
if (result->send_data(item_list))
join->error= 1;
}
else if (join->select_lex == join->unit->fake_select_lex)
{
/*
here we assume that the query will return at least two rows, so we
show "filesort" in EXPLAIN. Of course, sometimes we'll be wrong
and no filesort will be actually done, but executing all selects in
the UNION to provide precise EXPLAIN information will hardly be
appreciated :)
*/
char table_name_buffer[NAME_LEN];
item_list.empty();
/* id */
item_list.push_back(new Item_null);
/* select_type */
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type),
cs));
/* table */
{
SELECT_LEX *sl= join->unit->first_select();
uint len= 6, lastop= 0;
memcpy(table_name_buffer, "<union", 6);
for (; sl && len + lastop + 5 < NAME_LEN; sl= sl->next_select())
{
len+= lastop;
lastop= my_snprintf(table_name_buffer + len, NAME_LEN - len,
"%u,", sl->select_number);
}
if (sl || len + lastop >= NAME_LEN)
{
memcpy(table_name_buffer + len, "...>", 5);
len+= 4;
}
else
{
len+= lastop;
table_name_buffer[len - 1]= '>'; // change ',' to '>'
}
item_list.push_back(new Item_string(table_name_buffer, len, cs));
}
/* type */
item_list.push_back(new Item_string(join_type_str[JT_ALL],
strlen(join_type_str[JT_ALL]),
cs));
/* possible_keys */
item_list.push_back(item_null);
/* key*/
item_list.push_back(item_null);
/* key_len */
item_list.push_back(item_null);
/* ref */
item_list.push_back(item_null);
/* rows */
item_list.push_back(item_null);
/* extra */
if (join->unit->global_parameters->order_list.first)
item_list.push_back(new Item_string("Using filesort",
14, cs));
else
item_list.push_back(new Item_string("", 0, cs));
if (result->send_data(item_list))
join->error= 1;
}
else
{
table_map used_tables=0;
for (uint i=0 ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
TABLE *table=tab->table;
char buff[512],*buff_ptr=buff;
char buff1[512], buff2[512];
char table_name_buffer[NAME_LEN];
String tmp1(buff1,sizeof(buff1),cs);
String tmp2(buff2,sizeof(buff2),cs);
tmp1.length(0);
tmp2.length(0);
item_list.empty();
/* id */
item_list.push_back(new Item_uint((uint32)
join->select_lex->select_number));
/* select_type */
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type),
cs));
if (tab->type == JT_ALL && tab->select && tab->select->quick)
tab->type= JT_RANGE;
/* table */
if (table->derived_select_number)
{
/* Derived table name generation */
int len= my_snprintf(table_name_buffer, sizeof(table_name_buffer)-1,
"<derived%u>",
table->derived_select_number);
item_list.push_back(new Item_string(table_name_buffer, len, cs));
}
else
item_list.push_back(new Item_string(table->table_name,
strlen(table->table_name),
cs));
/* type */
item_list.push_back(new Item_string(join_type_str[tab->type],
strlen(join_type_str[tab->type]),
cs));
uint j;
/* possible_keys */
if (!tab->keys.is_clear_all())
{
for (j=0 ; j < table->keys ; j++)
{
if (tab->keys.is_set(j))
{
if (tmp1.length())
tmp1.append(',');
tmp1.append(table->key_info[j].name,
strlen(table->key_info[j].name),
system_charset_info);
}
}
}
if (tmp1.length())
item_list.push_back(new Item_string(tmp1.ptr(),tmp1.length(),cs));
else
item_list.push_back(item_null);
/* key key_len ref */
if (tab->ref.key_parts)
{
KEY *key_info=table->key_info+ tab->ref.key;
item_list.push_back(new Item_string(key_info->name,
strlen(key_info->name),
system_charset_info));
item_list.push_back(new Item_int((int32) tab->ref.key_length));
for (store_key **ref=tab->ref.key_copy ; *ref ; ref++)
{
if (tmp2.length())
tmp2.append(',');
tmp2.append((*ref)->name(), strlen((*ref)->name()),
system_charset_info);
}
item_list.push_back(new Item_string(tmp2.ptr(),tmp2.length(),cs));
}
else if (tab->type == JT_NEXT)
{
KEY *key_info=table->key_info+ tab->index;
item_list.push_back(new Item_string(key_info->name,
strlen(key_info->name),cs));
item_list.push_back(new Item_int((int32) key_info->key_length));
item_list.push_back(item_null);
}
else if (tab->select && tab->select->quick)
{
KEY *key_info=table->key_info+ tab->select->quick->index;
item_list.push_back(new Item_string(key_info->name,
strlen(key_info->name),cs));
item_list.push_back(new Item_int((int32) tab->select->quick->
max_used_key_length));
item_list.push_back(item_null);
}
else
{
item_list.push_back(item_null);
item_list.push_back(item_null);
item_list.push_back(item_null);
}
/* rows */
item_list.push_back(new Item_int((longlong) (ulonglong)
join->best_positions[i]. records_read,
21));
/* extra */
my_bool key_read=table->key_read;
if ((tab->type == JT_NEXT || tab->type == JT_CONST) &&
table->used_keys.is_set(tab->index))
key_read=1;
if (tab->info)
item_list.push_back(new Item_string(tab->info,strlen(tab->info),cs));
else
{
if (tab->select)
{
if (tab->use_quick == 2)
{
char buf[MAX_KEY/8+1];
sprintf(buff_ptr,"; Range checked for each record (index map: 0x%s)",
tab->keys.print(buf));
buff_ptr=strend(buff_ptr);
}
else
buff_ptr=strmov(buff_ptr,"; Using where");
}
if (key_read)
buff_ptr= strmov(buff_ptr,"; Using index");
if (table->reginfo.not_exists_optimize)
buff_ptr= strmov(buff_ptr,"; Not exists");
if (need_tmp_table)
{
need_tmp_table=0;
buff_ptr= strmov(buff_ptr,"; Using temporary");
}
if (need_order)
{
need_order=0;
buff_ptr= strmov(buff_ptr,"; Using filesort");
}
if (distinct & test_all_bits(used_tables,thd->used_tables))
buff_ptr= strmov(buff_ptr,"; Distinct");
if (buff_ptr == buff)
buff_ptr+= 2; // Skip inital "; "
item_list.push_back(new Item_string(buff+2,(uint) (buff_ptr - buff)-2,
cs));
}
// For next iteration
used_tables|=table->map;
if (result->send_data(item_list))
join->error= 1;
}
}
for (SELECT_LEX_UNIT *unit= join->select_lex->first_inner_unit();
unit;
unit= unit->next_unit())
{
if (mysql_explain_union(thd, unit, result))
DBUG_VOID_RETURN;
}
DBUG_VOID_RETURN;
}
int mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
{
DBUG_ENTER("mysql_explain_union");
int res= 0;
SELECT_LEX *first= unit->first_select();
for (SELECT_LEX *sl= first;
sl;
sl= sl->next_select())
{
// drop UNCACHEABLE_EXPLAIN, because it is for internal usage only
uint8 uncacheable= (sl->uncacheable & ~UNCACHEABLE_EXPLAIN);
sl->type= (((&thd->lex->select_lex)==sl)?
((thd->lex->all_selects_list != sl) ?
primary_key_name : "SIMPLE"):
((sl == first)?
((sl->linkage == DERIVED_TABLE_TYPE) ?
"DERIVED":
((uncacheable & UNCACHEABLE_DEPENDENT) ?
"DEPENDENT SUBQUERY":
(uncacheable?"UNCACHEABLE SUBQUERY":
"SUBQUERY"))):
((uncacheable & UNCACHEABLE_DEPENDENT) ?
"DEPENDENT UNION":
uncacheable?"UNCACHEABLE UNION":
"UNION")));
sl->options|= SELECT_DESCRIBE;
}
if (first->next_select())
{
unit->fake_select_lex->select_number= UINT_MAX; // jost for initialization
unit->fake_select_lex->type= "UNION RESULT";
unit->fake_select_lex->options|= SELECT_DESCRIBE;
if (!(res= unit->prepare(thd, result, SELECT_NO_UNLOCK | SELECT_DESCRIBE,
"")))
res= unit->exec();
res|= unit->cleanup();
}
else
{
thd->lex->current_select= first;
res= mysql_select(thd, &first->ref_pointer_array,
(TABLE_LIST*) first->table_list.first,
first->with_wild, first->item_list,
first->where,
first->order_list.elements +
first->group_list.elements,
(ORDER*) first->order_list.first,
(ORDER*) first->group_list.first,
first->having,
(ORDER*) thd->lex->proc_list.first,
first->options | thd->options | SELECT_DESCRIBE,
result, unit, first);
}
if (res > 0 || thd->net.report_error)
res= -1; // mysql_explain_select do not report error
DBUG_RETURN(res);
}
void st_select_lex::print(THD *thd, String *str)
{
if (!thd)
thd= current_thd;
str->append("select ", 7);
//options
if (options & SELECT_STRAIGHT_JOIN)
str->append("straight_join ", 14);
if ((thd->lex->lock_option == TL_READ_HIGH_PRIORITY) &&
(this == &thd->lex->select_lex))
str->append("high_priority ", 14);
if (options & SELECT_DISTINCT)
str->append("distinct ", 9);
if (options & SELECT_SMALL_RESULT)
str->append("sql_small_result ", 17);
if (options & SELECT_BIG_RESULT)
str->append("sql_big_result ", 15);
if (options & OPTION_BUFFER_RESULT)
str->append("sql_buffer_result ", 18);
if (options & OPTION_FOUND_ROWS)
str->append("sql_calc_found_rows ", 20);
if (!thd->lex->safe_to_cache_query)
str->append("sql_no_cache ", 13);
if (options & OPTION_TO_QUERY_CACHE)
str->append("sql_cache ", 10);
//Item List
bool first= 1;
List_iterator_fast<Item> it(item_list);
Item *item;
while ((item= it++))
{
if (first)
first= 0;
else
str->append(',');
item->print_item_w_name(str);
}
/*
from clause
TODO: support USING/FORCE/IGNORE index
*/
if (table_list.elements)
{
str->append(" from ", 6);
Item *next_on= 0;
for (TABLE_LIST *table= (TABLE_LIST *) table_list.first;
table;
table= table->next)
{
if (table->derived)
{
str->append('(');
table->derived->print(str);
str->append(") ");
str->append(table->alias);
}
else
{
str->append(table->db);
str->append('.');
str->append(table->real_name);
if (my_strcasecmp(table_alias_charset, table->real_name, table->alias))
{
str->append(' ');
str->append(table->alias);
}
}
if (table->on_expr && ((table->outer_join & JOIN_TYPE_LEFT) ||
!(table->outer_join & JOIN_TYPE_RIGHT)))
next_on= table->on_expr;
if (next_on)
{
str->append(" on(", 4);
next_on->print(str);
str->append(')');
next_on= 0;
}
TABLE_LIST *next_table;
if ((next_table= table->next))
{
if (table->outer_join & JOIN_TYPE_RIGHT)
{
str->append(" right join ", 12);
if (!(table->outer_join & JOIN_TYPE_LEFT) &&
table->on_expr)
next_on= table->on_expr;
}
else if (next_table->straight)
str->append(" straight_join ", 15);
else if (next_table->outer_join & JOIN_TYPE_LEFT)
str->append(" left join ", 11);
else
str->append(" join ", 6);
}
}
}
// Where
Item *cur_where= where;
if (join)
cur_where= join->conds;
if (cur_where)
{
str->append(" where ", 7);
cur_where->print(str);
}
// group by & olap
if (group_list.elements)
{
str->append(" group by ", 10);
print_order(str, (ORDER *) group_list.first);
switch (olap)
{
case CUBE_TYPE:
str->append(" with cube", 10);
break;
case ROLLUP_TYPE:
str->append(" with rollup", 12);
break;
default:
; //satisfy compiler
}
}
// having
Item *cur_having= having;
if (join)
cur_having= join->having;
if (cur_having)
{
str->append(" having ", 8);
cur_having->print(str);
}
if (order_list.elements)
{
str->append(" order by ", 10);
print_order(str, (ORDER *) order_list.first);
}
// limit
print_limit(thd, str);
// PROCEDURE unsupported here
}
/*
change select_result object of JOIN
SYNOPSIS
JOIN::change_result()
res new select_result object
RETURN
0 - OK
-1 - error
*/
int JOIN::change_result(select_result *res)
{
DBUG_ENTER("JOIN::change_result");
result= res;
if (!procedure && result->prepare(fields_list, select_lex->master_unit()))
{
DBUG_RETURN(-1);
}
DBUG_RETURN(0);
}
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