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mariadb/sql/sql_select.cc

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/* Copyright (C) 2000-2003 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 __GNUC__
#pragma implementation // gcc: Class implementation
#endif
#include "mysql_priv.h"
#include "sql_select.h"
#include "opt_ft.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" };
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 void join_free(JOIN *join, bool full);
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 *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(COND *conds,Item::cond_result *cond_value);
static COND *remove_eq_conds(COND *cond,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 skipp_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 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, key_map usable_keys);
static bool test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,
ha_rows select_limit, bool no_changes);
static int create_sort_index(THD *thd, JOIN_TAB *tab,ORDER *order,
ha_rows filesort_limit, ha_rows select_limit);
static int create_sort_index(THD *thd, JOIN_TAB *tab,ORDER *order,
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(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, 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 alloc_group_fields(JOIN *join,ORDER *group);
static bool make_sum_func_list(JOIN *join,List<Item> &fields);
// 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);
static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab);
static void init_sum_functions(Item_sum **func);
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);
/*
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;
fix_tables_pointers(lex->all_selects_list);
if (select_lex->next_select())
res=mysql_union(thd, lex, result, &lex->unit, 0);
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), 0);
if (res && result)
result->abort();
if (res || thd->net.report_error)
{
send_error(thd, 0, NullS);
res= 1;
}
delete result;
return res;
}
void relink_tables(SELECT_LEX *select_lex)
{
for (TABLE_LIST *cursor= (TABLE_LIST *) select_lex->table_list.first;
cursor;
cursor=cursor->next)
cursor->table= cursor->table_list->table;
}
void fix_tables_pointers(SELECT_LEX *select_lex)
{
if (select_lex->next_select_in_list())
{
/* Fix tables 'to-be-unioned-from' list to point at opened tables */
for (SELECT_LEX *sl= select_lex;
sl;
sl= sl->next_select_in_list())
relink_tables(sl);
}
}
void fix_tables_pointers(SELECT_LEX_UNIT *unit)
{
for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
{
relink_tables(sl);
for (SELECT_LEX_UNIT *un= sl->first_inner_unit(); un; un= un->next_unit())
fix_tables_pointers(un);
}
}
/*
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= thd->allow_sum_func;
thd->allow_sum_func= 0;
int 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;
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 subselect 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,
SELECT_LEX_UNIT *unit,
bool tables_and_fields_initied)
{
DBUG_ENTER("JOIN::prepare");
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;
select_lex->join= this;
union_part= (unit->first_select()->next_select() != 0);
/* Check that all tables, fields, conds and order are ok */
if ((tables_and_fields_initied ? 0 : (setup_tables(tables_list) ||
setup_wild(thd, tables_list,
fields_list,
&all_fields, wild_num))) ||
setup_ref_array(thd, rref_pointer_array, (fields_list.elements +
select_lex->with_sum_func +
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->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 */
if (having->with_sum_func)
having->split_sum_func(ref_pointer_array, all_fields);
}
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_item())
flag|=2;
}
if (flag == 3)
{
my_error(ER_MIX_OF_GROUP_FUNC_AND_FIELDS,MYF(0));
DBUG_RETURN(-1);
}
}
TABLE_LIST *table;
for (table=tables_list ; table ; table=table->next)
tables++;
}
procedure= setup_procedure(thd, proc_param, result, fields_list, &error);
if (error)
DBUG_RETURN(-1); /* purecov: inspected */
if (procedure)
{
if (setup_new_fields(thd, tables_list, fields_list, all_fields,
procedure->param_fields))
{ /* purecov: inspected */
delete procedure; /* purecov: inspected */
DBUG_RETURN(-1); /* 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 */
delete procedure; /* purecov: inspected */
DBUG_RETURN(-1); /* 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));
delete procedure;
DBUG_RETURN(-1);
}
#endif
if (order && (procedure->flags & PROC_NO_SORT))
{ /* purecov: inspected */
my_message(0,"Can't use order with this procedure",MYF(0)); /* purecov: inspected */
delete procedure; /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
}
/* Init join struct */
count_field_types(&tmp_table_param, all_fields, 0);
this->group= group_list != 0;
row_limit= ((select_distinct || order || group_list) ? HA_POS_ERROR :
unit->select_limit_cnt);
/* select_limit is used to decide if we are likely to scan the whole table */
select_limit= unit->select_limit_cnt;
if (having || (select_options & OPTION_FOUND_ROWS))
select_limit= HA_POS_ERROR;
do_send_rows = (unit->select_limit_cnt) ? 1 : 0;
this->unit= unit;
#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));
delete procedure;
DBUG_RETURN(-1);
}
#endif
if (!procedure && result->prepare(fields_list, unit))
{ /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
DBUG_RETURN(0); // All OK
}
/*
global select optimisation.
return 0 - success
1 - go out
-1 - go out with cleaning
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;
#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(conds,&cond_value);
if (thd->net.report_error)
{
// quick abort
delete procedure;
error= thd->is_fatal_error ? -1 : 1;
DBUG_PRINT("error",("Error from optimize_cond"));
DBUG_RETURN(error);
}
if (cond_value == Item::COND_FALSE ||
(!unit->select_limit_cnt && !(select_options & OPTION_FOUND_ROWS)))
{ /* Impossible cond */
zero_result_cause= "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;
if ((res=opt_sum_query(tables_list, all_fields, conds)))
{
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
}
}
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);
}
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))
{
zero_result_cause= "no matching row in const table";
DBUG_PRINT("error",("Error: %s", zero_result_cause));
select_options= 0; //TODO why option in return_zero_rows was droped
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; /* purecov: inspected */
DBUG_RETURN(1);
}
if (const_tables && !thd->locked_tables &&
!(select_options & SELECT_NO_UNLOCK))
{
TABLE **table, **end;
for (table=this->table, end=table + const_tables ;
table != end;
table++)
{
/* BDB tables require that we call index_end() before doing an unlock */
if ((*table)->key_read)
{
(*table)->key_read=0;
(*table)->file->extra(HA_EXTRA_NO_KEYREAD);
}
(*table)->file->index_end();
}
mysql_unlock_some_tables(thd, this->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,&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;
}
order= remove_const(this, order, conds, &simple_order);
if (group_list || tmp_table_param.sum_func_count)
{
if (! hidden_group_fields)
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, 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)
order=0;
group=1; // For end_write_group
}
else
group_list= 0;
}
else if (thd->is_fatal_error) // End of memory
DBUG_RETURN(1);
}
group_list= remove_const(this, group_list, conds, &simple_group);
if (!group_list && group)
{
order=0; // The output has only one row
simple_order=1;
}
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,
&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));
/*
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;
if (table_h->db_type == DB_TYPE_INNODB)
table_h->file->extra(HA_EXTRA_DONT_USE_CURSOR_TO_UPDATE);
}
}
#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 ((order || group_list) && join_tab[const_tables].type != JT_ALL &&
join_tab[const_tables].type != JT_FT &&
(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
}
if (select_options & SELECT_DESCRIBE)
{
error= 0;
DBUG_RETURN(0);
}
tmp_having= having;
having= 0;
/* Perform FULLTEXT search before all regular searches */
init_ftfuncs(thd, select_lex, test(order));
/* 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);
if (!(exec_tmp_table1 =
create_tmp_table(thd, &tmp_table_param, all_fields,
((!simple_group && !procedure &&
!(test_flags & TEST_NO_KEY_GROUP)) ?
group_list : (ORDER*) 0),
group_list ? 0 : select_distinct,
group_list && simple_group,
select_options,
(order == 0 || skip_sort_order) ? select_limit :
HA_POS_ERROR)))
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 (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, &join_tab[const_tables], group_list,
HA_POS_ERROR, HA_POS_ERROR) ||
make_sum_func_list(this, all_fields) ||
alloc_group_fields(this, group_list))
DBUG_RETURN(1);
group_list=0;
}
else
{
if (make_sum_func_list(this, all_fields))
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, &join_tab[const_tables], 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 *join_tab= this->join_tab+tables-1;
do
{
if (used_tables & join_tab->table->map)
break;
join_tab->not_used_in_distinct=1;
} while (join_tab-- != this->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(&this->join_tab[const_tables],
order, unit->select_limit_cnt, 0))
order=0;
}
}
if (select_lex != &thd->lex.select_lex &&
select_lex->linkage != DERIVED_TABLE_TYPE)
{
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 (setup_tables(tables_list))
DBUG_RETURN(1);
// Reset of sum functions
first_record= 0;
if (sum_funcs)
{
Item_sum *func, **func_ptr= sum_funcs;
while ((func= *(func_ptr++)))
func->null_value= 1;
}
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);
}
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);
}
if (items0)
memcpy(ref_pointer_array, items0, ref_pointer_array_size);
if (tmp_join)
restore_tmp();
DBUG_RETURN(0);
}
/*
Exec select
*/
void
JOIN::exec()
{
int tmp_error;
DBUG_ENTER("JOIN::exec");
error= 0;
if (procedure)
{
if (procedure->change_columns(fields_list) ||
result->prepare(fields_list, unit))
DBUG_VOID_RETURN;
}
if (!tables_list)
{ // 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(fields_list,1);
if (!having || having->val_int())
{
if (do_send_rows && (procedure ? (procedure->send_row(fields_list) ||
procedure->end_of_records())
: result->send_data(fields_list)))
error= 1;
else
{
error= (int) result->send_eof();
send_records=1;
}
}
else
error=(int) result->send_eof();
}
DBUG_VOID_RETURN;
}
if (zero_result_cause)
{
(void) return_zero_rows(this, result, tables_list, fields_list,
tmp_table_param.sum_func_count != 0 &&
!group_list,
select_options,
zero_result_cause,
having, procedure,
unit);
DBUG_VOID_RETURN;
}
if (select_options & SELECT_DESCRIBE)
{
if (!order && !no_order)
order=group_list;
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);
DBUG_VOID_RETURN;
}
/* Perform FULLTEXT search before all regular searches */
//init_ftfuncs(thd, select_lex, test(order));
JOIN *curr_join= this;
List<Item> *curr_all_fields= &all_fields;
List<Item> *curr_fields_list= &fields_list;
TABLE *curr_tmp_table= 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;
memcpy(ref_pointer_array, items1, ref_pointer_array_size);
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 */
join_free(curr_join, 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)))
DBUG_VOID_RETURN;
curr_join->exec_tmp_table2= exec_tmp_table2;
}
if (group_list)
{
thd->proc_info= "Creating sort index";
if (create_sort_index(thd, curr_join->join_tab, curr_join->group_list,
HA_POS_ERROR, HA_POS_ERROR) ||
alloc_group_fields(curr_join, curr_join->group_list))
{
DBUG_VOID_RETURN;
}
curr_join->group_list= 0;
}
thd->proc_info="Copying to group table";
tmp_error= -1;
if (make_sum_func_list(curr_join, *curr_all_fields) ||
(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;
memcpy(ref_pointer_array, items2, ref_pointer_array_size);
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 */
join_free(curr_join, 0); /* Free quick selects */
if (select_distinct && ! 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_join->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)))
{
alloc_group_fields(curr_join, curr_join->group_list);
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;
memcpy(ref_pointer_array, items3, ref_pointer_array_size);
if (make_sum_func_list(curr_join, *curr_all_fields) ||
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 *table= &curr_join->join_tab[const_tables];
table_map used_tables= curr_join->const_table_map | table->table->map;
Item* sort_table_cond= make_cond_for_table(curr_join->tmp_having,
used_tables,
used_tables);
if (sort_table_cond)
{
if (!table->select)
if (!(table->select= new SQL_SELECT))
DBUG_VOID_RETURN;
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)))
DBUG_VOID_RETURN;
table->select_cond=table->select->cond;
table->select_cond->top_level_item();
DBUG_EXECUTE("where",print_where(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(conds,"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 *table= &curr_join->join_tab[const_tables+1];
JOIN_TAB *end_table= &curr_join->join_tab[tables];
for (; table < end_table ; 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 (table->select_cond || (table->keyuse && !table->on_expr))
{
/* We have to sort all rows */
curr_join->select_limit= HA_POS_ERROR;
break;
}
}
}
if (create_sort_index(thd, &curr_join->join_tab[curr_join->const_tables],
curr_join->group_list ?
curr_join->group_list : curr_join->order,
curr_join->select_limit, unit->select_limit_cnt))
DBUG_VOID_RETURN;
}
}
curr_join->having= curr_join->tmp_having;
thd->proc_info="Sending data";
error= thd->net.report_error ||
do_select(curr_join, curr_fields_list, NULL, procedure);
DBUG_VOID_RETURN;
}
/*
Clean up join. Return error that hold JOIN.
*/
int
JOIN::cleanup(THD *thd)
{
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++)
{
delete tab->select;
delete tab->quick;
x_free(tab->cache.buff);
}
}
tmp_join->tmp_join= 0;
DBUG_RETURN(tmp_join->cleanup(thd));
}
lock=0; // It's faster to unlock later
join_free(this, 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 *unit= select_lex->first_inner_unit();
unit != 0;
unit= unit->next_unit())
{
error|= 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, bool tables_and_fields_initied)
{
int err;
bool free_join= 1;
DBUG_ENTER("mysql_select");
JOIN *join;
if (select_lex->join != 0)
{
//here is EXPLAIN of subselect or derived table
join= select_lex->join;
join->result= result;
if (!join->procedure && result->prepare(join->fields_list, unit))
{
DBUG_RETURN(-1);
}
join->select_options= select_options;
free_join= 0;
}
else
{
join= new JOIN(thd, fields, select_options, result);
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, tables_and_fields_initied))
{
DBUG_RETURN(-1);
}
}
if ((err= join->optimize()))
{
if (err == -1)
DBUG_RETURN(join->error);
DBUG_ASSERT(err == 1);
goto err; // 1
}
if (thd->net.report_error)
goto err;
join->exec();
err:
if (free_join)
{
JOIN *curr_join= (join->need_tmp&&join->tmp_join?
(join->tmp_join->error=join->error,join->tmp_join):
join);
thd->limit_found_rows= curr_join->send_records;
thd->examined_row_count= curr_join->examined_rows;
thd->proc_info="end";
err= join->cleanup(thd);
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(SQL_SELECT *select,TABLE *table,
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(keys,(table_map) 0,limit))
== 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,found_ref,refs,key,const_ref,eq_part;
table_map found_const_table_map,all_table_map;
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;
table_vector[i]=s->table=table=tables->table;
table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);// record count
table->quick_keys=0;
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|= (key_map) 1 << key; // QQ: remove this ?
refs=const_ref=eq_part=0;
do
{
if (keyuse->val->type() != Item::NULL_ITEM)
{
if (!((~found_const_table_map) & keyuse->used_tables))
const_ref|= (key_map) 1 << keyuse->keypart;
else
refs|=keyuse->used_tables;
eq_part|= (uint) 1 << keyuse->keypart;
}
keyuse++;
} while (keyuse->table == table && keyuse->key == key);
if (eq_part == PREV_BITS(uint,table->key_info[key].key_parts) &&
(table->key_info[key].flags & 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 was (s->read_time*5), but this was too low with small rows
*/
s->worst_seeks= (double) s->found_records / 5;
if (s->worst_seeks < 2.0) // Fix for small tables
s->worst_seeks=2.0;
/* if (s->type == JT_EQ_REF)
continue; */
if (s->const_keys)
{
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(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)
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,const_level; // QQ: Remove const_level
bool eq_func;
bool exists_optimize;
} KEY_FIELD;
/* merge new key definitions to old ones, remove those not used in both */
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 (old->val->eq(new_fields->val, old->field->binary()))
{
old->level=old->const_level=and_level;
old->exists_optimize&=new_fields->exists_optimize;
}
}
else if (old->val->eq(new_fields->val, old->field->binary()) &&
old->eq_func && new_fields->eq_func)
{
old->level=old->const_level=and_level;
old->exists_optimize&=new_fields->exists_optimize;
}
else // Impossible; remove 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 && old->const_level != and_level)
{ // Not used in all levels
if (old == --first_free)
break;
*old= *first_free; // Remove old value
continue;
}
old++;
}
return first_free;
}
static void
add_key_field(KEY_FIELD **key_fields,uint and_level,
Field *field,bool eq_func,Item *value,
table_map usable_tables)
{
bool exists_optimize=0;
if (!(field->flags & PART_KEY_FLAG))
{
// Don't remove column IS NULL on a LEFT JOIN table
if (!eq_func || !value || value->type() != Item::NULL_ITEM ||
!field->table->maybe_null || field->null_ptr)
return; // Not a key. Skip it
exists_optimize=1;
}
else
{
table_map used_tables=0;
if (value && (used_tables=value->used_tables()) &
(field->table->map | RAND_TABLE_BIT))
return;
if (!(usable_tables & field->table->map))
{
if (!eq_func || !value || value->type() != Item::NULL_ITEM ||
!field->table->maybe_null || field->null_ptr)
return; // Can't use left join optimize
exists_optimize=1;
}
else
{
JOIN_TAB *stat=field->table->reginfo.join_tab;
key_map possible_keys= (field->key_start &
field->table->keys_in_use_for_query);
stat[0].keys|= possible_keys; // Add possible keys
if (!value)
{ // Probably BETWEEN or IN
stat[0].const_keys |= possible_keys;
return; // Can't be used as eq key
}
/* 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
*/
stat[0].key_dependent|=used_tables;
if (value->const_item())
stat[0].const_keys |= 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 */
if (!eq_func ||
field->result_type() == STRING_RESULT &&
value->result_type() != STRING_RESULT &&
field->cmp_type() != value->result_type())
return;
}
}
/* Store possible eq field */
(*key_fields)->field=field;
(*key_fields)->eq_func=eq_func;
(*key_fields)->val=value;
(*key_fields)->level=(*key_fields)->const_level=and_level;
(*key_fields)->exists_optimize=exists_optimize;
(*key_fields)++;
}
static void
add_key_fields(JOIN_TAB *stat,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(stat,key_fields,and_level,item,usable_tables);
for (; org_key_fields != *key_fields ; org_key_fields++)
{
if (org_key_fields->const_level == org_key_fields->level)
org_key_fields->const_level=org_key_fields->level= *and_level;
else
org_key_fields->const_level= *and_level;
}
}
else
{
(*and_level)++;
add_key_fields(stat,key_fields,and_level,li++,usable_tables);
Item *item;
while ((item=li++))
{
KEY_FIELD *start_key_fields= *key_fields;
(*and_level)++;
add_key_fields(stat,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:
if (cond_func->key_item()->real_item()->type() == Item::FIELD_ITEM)
add_key_field(key_fields,*and_level,
((Item_field*) (cond_func->key_item()->real_item()))
->field,
0,(Item*) 0,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)
{
add_key_field(key_fields,*and_level,
((Item_field*) (cond_func->arguments()[0])->real_item())
->field,
equal_func,
(cond_func->arguments()[1]),usable_tables);
}
if (cond_func->arguments()[1]->real_item()->type() == Item::FIELD_ITEM &&
cond_func->functype() != Item_func::LIKE_FUNC)
{
add_key_field(key_fields,*and_level,
((Item_field*) (cond_func->arguments()[1])->real_item())
->field,
equal_func,
(cond_func->arguments()[0]),usable_tables);
}
break;
}
case Item_func::OPTIMIZE_NULL:
/* column_name IS [NOT] NULL */
if (cond_func->arguments()[0]->real_item()->type() == Item::FIELD_ITEM)
{
add_key_field(key_fields,*and_level,
((Item_field*) (cond_func->arguments()[0])->real_item())
->field,
cond_func->functype() == Item_func::ISNULL_FUNC,
new Item_null, 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_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->exists_optimize)
{
for (uint key=0 ; key < form->keys ; key++)
{
if (!(form->keys_in_use_for_query & (((key_map) 1) << 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.used_tables=key_field->val->used_tables();
VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
}
}
}
}
/* Mark that we can optimize LEFT JOIN */
if (key_field->val->type() == Item::NULL_ITEM &&
!key_field->field->real_maybe_null())
key_field->field->table->reginfo.not_exists_optimize=1;
}
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 ((functype == Item_func::GE_FUNC ||
functype == Item_func::GT_FUNC) &&
arg0->type() == Item::FUNC_ITEM &&
arg0->functype() == Item_func::FT_FUNC &&
arg1->const_item() && arg1->val()>0)
cond_func=(Item_func_match *) arg0;
else if ((functype == Item_func::LE_FUNC ||
functype == Item_func::LT_FUNC) &&
arg1->type() == Item::FUNC_ITEM &&
arg1->functype() == Item_func::FT_FUNC &&
arg0->const_item() && arg0->val()>0)
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;
/*
I'm (Sergei) too lazy to implement proper recursive descent here,
and anyway, nobody will use such a stupid queries
that will require it :-)
May be later...
*/
while ((item=li++))
{
if (item->type() == Item::FUNC_ITEM &&
((Item_func *)item)->functype() == Item_func::FT_FUNC)
{
cond_func=(Item_func_match *)item;
break;
}
}
}
}
if (!cond_func || cond_func->key == NO_SUCH_KEY)
return;
KEYUSE keyuse;
keyuse.table= cond_func->table;
keyuse.val = cond_func;
keyuse.key = cond_func->key;
#define FT_KEYPART (MAX_REF_PARTS+10)
keyuse.keypart=FT_KEYPART;
keyuse.used_tables=cond_func->key_item()->used_tables();
VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
}
static int
sort_keyuse(KEYUSE *a,KEYUSE *b)
{
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);
return test(a->used_tables) - test(b->used_tables); // Place const first
}
/*
Update keyuse array with all possible keys we can use to fetch rows
join_tab is a array in tablenr_order
stat is a reference array in 'prefered' order.
*/
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;
if (!(key_fields=(KEY_FIELD*)
thd->alloc(sizeof(key_fields[0])*(thd->cond_count+1)*2)))
return TRUE; /* purecov: inspected */
and_level=0; end=key_fields;
if (cond)
add_key_fields(join_tab,&end,&and_level,cond,normal_tables);
for (i=0 ; i < tables ; i++)
{
if (join_tab[i].on_expr)
{
add_key_fields(join_tab,&end,&and_level,join_tab[i].on_expr,
join_tab[i].table->map);
}
}
if (my_init_dynamic_array(keyuse,sizeof(KEYUSE),20,64))
return TRUE;
/* fill keyuse with found key parts */
for (KEY_FIELD *field=key_fields ; field != end ; field++)
add_key_part(keyuse,field);
}
if (select_lex->ftfunc_list->elements)
{
add_ft_keys(keyuse,join_tab,cond,normal_tables);
}
/*
Remove ref if there is a keypart which is a ref and a const.
Remove keyparts without previous keyparts.
Special treatment for ft-keys.
*/
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] |=
(key_part_map) 1 << use->keypart;
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|= (key_map) 1 << use->key;
save_pos++;
}
i=(uint) (save_pos-(KEYUSE*) keyuse->buffer);
VOID(set_dynamic(keyuse,(gptr) &end,i));
keyuse->elements=i;
}
return FALSE;
}
/*****************************************************************************
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;
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_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);
start_key=keyuse;
do
{
uint keypart=keyuse->keypart;
do
{
if (!ft_key)
{
table_map map;
if (!(rest_tables & keyuse->used_tables))
{
found_part|= (key_part_map) 1 << keypart;
found_ref|= keyuse->used_tables;
}
/*
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 and to avoid bad matches,
we don't make rec less than 100.
*/
if (keyuse->used_tables &
(map=(keyuse->used_tables & ~join->const_table_map)))
{
uint tablenr;
for (tablenr=0 ; ! (map & 1) ; map>>=1, tablenr++) ;
if (map == 1) // Only one table
{
TABLE *tmp_table=join->all_tables[tablenr];
if (rec > tmp_table->file->records && rec > 100)
rec=max(tmp_table->file->records,100);
}
}
}
keyuse++;
} while (keyuse->table == table && keyuse->key == key &&
keyuse->keypart == keypart);
} 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 == 0)
rec=1L; // 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
{
/*
Check if we found full key
*/
if (found_part == PREV_BITS(uint,keyinfo->key_parts))
{ /* use eq key */
max_key_part= (uint) ~0;
if ((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_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 & ((key_map) 1 << key))
records= (double) table->quick_rows[key];
else
records= (double) s->records/rec; // quick_range couldn't use key!
}
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
}
}
if (table->used_keys & ((key_map) 1 << 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*(records+keys_per_block-1)/
keys_per_block);
}
else
tmp=record_count*min(records,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) & HA_ONLY_WHOLE_INDEX))
{
max_key_part=max_part_bit(found_part);
/*
Check if quick_range could determinate how many rows we
will match
*/
if (table->quick_keys & ((key_map) 1 << 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 (dupplicates) 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;
if (!(rec_per_key=(double)
keyinfo->rec_per_key[keyinfo->key_parts-1]))
rec_per_key=(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 (table->used_keys & ((key_map) 1 << 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 && best_key) &&
!(s->table->force_index && best_key))
{ // Check full join
if (s->on_expr)
{
tmp=rows2double(s->found_records); // Can't use read cache
}
else
{
tmp=(double) s->read_time;
/* Calculate time to read through cache */
tmp*=(1.0+floor((double) cache_record_length(join,idx)*
record_count /
(double) thd->variables.join_buff_size));
}
if (best == DBL_MAX ||
(tmp + record_count/(double) TIME_FOR_COMPARE*s->found_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(s->found_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(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(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;
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=0;
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 || !(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;
do
{
if (!((~used_tables) & keyuse->used_tables))
{
if (keyparts == keyuse->keypart)
{
keyparts++;
length+=keyinfo->key_part[keyuse->keypart].store_length;
}
}
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;
keyuse=org_keyuse;
store_key **ref_key=j->ref.key_copy;
byte *key_buff=j->ref.key_buff;
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->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);
key_buff+=keyinfo->key_part[i].store_length;
}
} /* not ftkey */
*ref_key=0; // end_marker
if (j->type == JT_FT) /* no-op */;
else if (j->type == JT_CONST)
j->table->const_table=1;
else if (((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY))
!= HA_NOSAME) ||
keyparts != keyinfo->key_parts)
j->type=JT_REF; /* Must read with repeat */
else if (ref_key == j->ref.key_copy)
{
/*
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)
{
bool error;
THD *thd=current_thd;
ha_rows cuted_fields=thd->cuted_fields;
thd->count_cuted_fields=1;
error= item->save_in_field(field, 1);
thd->count_cuted_fields=0;
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->sum_funcs=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 cacheing */
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= (uint) ~0; /* 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;
}
static bool
make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
{
DBUG_ENTER("make_join_select");
if (select)
{
table_map used_tables;
if (join->tables > 1)
cond->update_used_tables(); // Tablenr may have changed
{ // 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) | 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|= 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_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)
{
DBUG_EXECUTE("where",print_where(tmp,tab->table->table_name););
SQL_SELECT *sel=tab->select=(SQL_SELECT*)
join->thd->memdup((gptr) select, sizeof(SQL_SELECT));
if (!sel)
DBUG_RETURN(1); // End of memory
tab->select_cond=sel->cond=tmp;
sel->head=tab->table;
if (tab->quick)
{
/* Use quick key read if it's a constant and it's not used
with key reading */
if (tab->needed_reg == 0 && 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=0;
sel->needed_reg=0;
}
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 && tab->table->reginfo.impossible_range)
DBUG_RETURN(1);
}
else if (tab->type == JT_ALL && ! use_quick_range)
{
if (tab->const_keys &&
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 & ~ tab->const_keys && i > 0) ||
(tab->const_keys && 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);
if (sel->test_quick_select(tab->keys,
used_tables & ~ current_map,
(join->select_options &
OPTION_FOUND_ROWS ?
HA_POS_ERROR :
join->unit->select_limit_cnt)) < 0)
DBUG_RETURN(1); // Impossible range
sel->cond=orig_cond;
}
else
{
sel->needed_reg=tab->needed_reg;
sel->quick_keys=0;
}
if ((sel->quick_keys | sel->needed_reg) & ~tab->checked_keys)
{
tab->keys=sel->quick_keys | sel->needed_reg;
tab->use_quick= (sel->needed_reg &&
(!select->quick_keys ||
(select->quick &&
(select->quick->records >= 100L)))) ?
2 : 1;
sel->read_tables= used_tables;
}
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;
SELECT_LEX *select_lex = &(join->thd->lex.select_lex);
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 */
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;
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;
table->file->index_init(tab->ref.key);
tab->read_first_record= join_read_key;
tab->read_record.read_record= join_no_more_records;
if (table->used_keys & ((key_map) 1 << tab->ref.key) &&
!table->no_keyread)
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
break;
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;
table->file->index_init(tab->ref.key);
tab->read_first_record= join_read_always_key;
tab->read_record.read_record= join_read_next_same;
if (table->used_keys & ((key_map) 1 << tab->ref.key) &&
!table->no_keyread)
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
break;
case JT_FT:
table->status=STATUS_NO_RECORD;
table->file->index_init(tab->ref.key);
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
*/
table->status=STATUS_NO_RECORD;
if (i != join->const_tables && !(options & SELECT_NO_JOIN_CACHE) &&
tab->use_quick != 2 && !tab->on_expr)
{
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)
{
select_lex->options|=QUERY_NO_GOOD_INDEX_USED;
tab->read_first_record= join_init_quick_read_record;
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)
{
statistic_increment(select_range_count, &LOCK_status);
}
else
{
select_lex->options|=QUERY_NO_INDEX_USED;
statistic_increment(select_scan_count, &LOCK_status);
}
}
else
{
if (tab->select && tab->select->quick)
{
statistic_increment(select_full_range_join_count, &LOCK_status);
}
else
{
select_lex->options|=QUERY_NO_INDEX_USED;
statistic_increment(select_full_join_count, &LOCK_status);
}
}
if (!table->no_keyread)
{
if (tab->select && tab->select->quick &&
table->used_keys & ((key_map) 1 << tab->select->quick->index))
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
else if (table->used_keys && ! (tab->select && tab->select->quick))
{ // Only read index tree
tab->index=find_shortest_key(table, table->used_keys);
tab->table->file->index_init(tab->index);
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);
}
static void
join_free(JOIN *join, bool full)
{
JOIN_TAB *tab,*end;
DBUG_ENTER("join_free");
if (join->table)
{
/*
Only a sorted table may be cached. This sorted table is always the
first non const table in join->table
*/
if (join->tables > join->const_tables) // Test for not-const tables
free_io_cache(join->table[join->const_tables]);
if (join->select_lex->dependent && !full)
{
for (tab=join->join_tab,end=tab+join->tables ; tab != end ; tab++)
{
if (tab->table)
{
if (tab->table->key_read)
{
tab->table->key_read= 0;
tab->table->file->extra(HA_EXTRA_NO_KEYREAD);
}
/* Don't free index if we are using read_record */
if (!tab->read_record.table)
tab->table->file->index_end();
}
}
}
else
{
for (tab=join->join_tab,end=tab+join->tables ; tab != end ; tab++)
{
delete tab->select;
delete tab->quick;
x_free(tab->cache.buff);
tab->cache.buff= 0;
if (tab->table)
{
if (tab->table->key_read)
{
tab->table->key_read= 0;
tab->table->file->extra(HA_EXTRA_NO_KEYREAD);
}
/* Don't free index if we are using read_record */
if (!tab->read_record.table)
tab->table->file->index_end();
/*
We need to reset this for next select
(Tested in part_of_refkey)
*/
tab->table->reginfo.join_tab= 0;
}
end_read_record(&tab->read_record);
}
join->table= 0;
}
}
/*
We are not using tables anymore
Unlock all tables. We may be in an INSERT .... SELECT statement.
*/
if (join->lock && join->thd->lock &&
!(join->select_options & SELECT_NO_UNLOCK))
{
mysql_unlock_read_tables(join->thd, join->lock);// Don't free join->lock
join->lock=0;
}
if (full)
{
join->group_fields.delete_elements();
join->tmp_table_param.copy_funcs.delete_elements();
join->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)
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;
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();
if (!(order->depend_map & RAND_TABLE_BIT)) // Not item_sum() or RAND()
{
for (JOIN_TAB **tab=join->map2table;
depend_map ;
tab++, depend_map>>=1)
{
if (depend_map & 1)
order->depend_map|=(*tab)->ref.depend_map;
}
}
}
}
/*
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 *simple_order)
{
if (join->tables == join->const_tables)
return 0; // No need to sort
DBUG_ENTER("remove_const");
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;
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)
*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 (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
}
}
}
*prev_ptr= order; // use this entry
prev_ptr= &order->next;
}
*prev_ptr=0;
if (!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);
}
if (procedure)
{
if (result->prepare(fields, unit)) // This hasn't been done yet
DBUG_RETURN(-1);
}
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);
}
if (tables) // Not from do_select()
{
/* Close open cursors */
for (TABLE_LIST *table=tables; table ; table=table->next)
table->table->file->index_end();
}
result->send_eof(); // Should be safe
}
DBUG_RETURN(0);
}
static void clear_tables(JOIN *join)
{
for (uint i=0 ; 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(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(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 *left_item= func->arguments()[0];
Item *right_item= func->arguments()[1];
Item_func::Functype functype= func->functype();
if (right_item->eq(field,0) && left_item != value)
{
Item *tmp=value->new_item();
if (tmp)
{
func->arguments()[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)
{
Item *tmp=value->new_item();
if (tmp)
{
func->arguments()[0] = value = tmp;
func->update_used_tables();
if ((functype == Item_func::EQ_FUNC || functype == Item_func::EQUAL_FUNC)
&& and_father != cond && !right_item->const_item())
{
func->arguments()[0] = func->arguments()[1]; // For easy check
func->arguments()[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();
}
}
}
static void
propagate_cond_constants(I_List<COND_CMP> *save_list,COND *and_level,
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(&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++))
if (!cond_cmp->cmp_func->arguments()[0]->const_item())
change_cond_ref_to_const(&save,cond_cmp->and_level,
cond_cmp->and_level,
cond_cmp->cmp_func->arguments()[0],
cond_cmp->cmp_func->arguments()[1]);
}
}
else if (and_level != 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;
bool left_const= func->arguments()[0]->const_item();
bool right_const=func->arguments()[1]->const_item();
if (!(left_const && right_const) &&
(func->arguments()[0]->result_type() ==
(func->arguments()[1]->result_type())))
{
if (right_const)
{
func->arguments()[1]=resolve_const_item(func->arguments()[1],
func->arguments()[0]);
func->update_used_tables();
change_cond_ref_to_const(save_list,and_level,and_level,
func->arguments()[0],
func->arguments()[1]);
}
else if (left_const)
{
func->arguments()[0]=resolve_const_item(func->arguments()[0],
func->arguments()[1]);
func->update_used_tables();
change_cond_ref_to_const(save_list,and_level,and_level,
func->arguments()[1],
func->arguments()[0]);
}
}
}
}
}
static COND *
optimize_cond(COND *conds,Item::cond_result *cond_value)
{
if (!conds)
{
*cond_value= Item::COND_TRUE;
return conds;
}
/* change field = field to field = const for each found field = const */
DBUG_EXECUTE("where",print_where(conds,"original"););
propagate_cond_constants((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(conds,cond_value) ;
DBUG_EXECUTE("info",print_where(conds,"after remove"););
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 )
*/
static COND *
remove_eq_conds(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(item,&tmp_cond_value);
if (!new_item)
{
#ifdef DELETE_ITEMS
delete item; // This may be shared
#endif
li.remove();
}
else if (item != new_item)
{
#ifdef DELETE_ITEMS
delete item; // This may be shared
#endif
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->fix_fields(current_thd,0, &cond);
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();
THD *thd=current_thd;
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->insert_id())
{
#ifndef EMBEDDED_LIBRARY
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->insert_id(),
21))))
{
cond=new_cond;
cond->fix_fields(thd, 0, &cond);
}
thd->insert_id(0); // 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
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
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
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)
{
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),
maybe_null, 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),
maybe_null, 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);
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 > 255)
return new Field_blob(item_sum->max_length,maybe_null,
item->name,table,item->charset());
return new Field_string(item_sum->max_length,maybe_null,
item->name,table,item->charset());
case ROW_RESULT:
default:
// This case should never be choosen
DBUG_ASSERT(0);
return 0;
}
}
thd->fatal_error();
return 0; // Error
}
case Item::FIELD_ITEM:
{
Field *org_field=((Item_field*) item)->field,*new_field;
*from_field=org_field;
// The following should always be true
if ((new_field= org_field->new_field(&thd->mem_root,table)))
{
if (modify_item)
((Item_field*) item)->result_field= new_field;
else
new_field->field_name=item->name;
if (org_field->maybe_null())
new_field->flags&= ~NOT_NULL_FLAG; // Because of outer join
}
return new_field;
}
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:
{
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:
if (item->max_length > 255)
new_field= new Field_blob(item->max_length,maybe_null,
item->name,table,item->str_value.charset());
else
new_field= new Field_string(item->max_length,maybe_null,
item->name,table,item->str_value.charset());
break;
case ROW_RESULT:
default:
// This case should never be choosen
DBUG_ASSERT(0);
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;
}
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)
{
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;
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%s_%lx_%i", mysql_tmpdir, tmp_file_prefix,
current_pid, temp_pool_slot);
else // if we run out of slots or we are not using tempool
sprintf(path,"%s%s%lx_%lx_%x",mysql_tmpdir,tmp_file_prefix,current_pid,
thd->thread_id, thd->tmp_table++);
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))
{
bitmap_clear_bit(&temp_pool, temp_pool_slot);
DBUG_RETURN(NULL); /* purecov: inspected */
}
if (!(param->copy_field=copy=new Copy_field[field_count]))
{
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;
/*
This must be "" as field may refer to it after tempory table is dropped
*/
table->table_name= (char*) "";
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->derived_select_number= 0;
table->db_low_byte_first=1; // True for HEAP and MyISAM
table->temp_pool_slot = temp_pool_slot;
table->copy_blobs= 1;
/* 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 *arg= ((Item_sum*) item)->args[i];
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);
if (!new_field)
goto err; // Should be OOM
tmp_from_field++;
*(reg_field++)= new_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++;
}
((Item_sum*) item)->args[i]= new Item_field(new_field);
}
}
}
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,
not_all_columns || group !=0);
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;
}
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)
{
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->record[2]= 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
}
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
}
param->copy_field_end=copy;
param->recinfo=recinfo;
store_record(table,2); // 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
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;
for (; group ; group=group->next,key_part_info++)
{
Field *field=(*group->item)->tmp_table_field();
bool maybe_null=(*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)
{
group->buff=(char*) group_buff;
if (!(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]);
group->field->move_field((char*) ++group->buff);
group_buff++;
}
else
group->field->move_field((char*) group_buff);
group_buff+= key_part_info->length;
}
keyinfo->key_length+= key_part_info->length;
}
}
if (distinct)
{
/*
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));
set_if_smaller(table->max_rows, rows_limit);
param->end_write_records= rows_limit;
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;
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;
}
/* Set table_name for easier debugging */
table->table_name= base_name(tmpname);
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 */
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->db_stat && entry->file)
{
(void) entry->file->close();
delete entry->file;
}
if (!(test_flags & TEST_KEEP_TMP_TABLES) || entry->db_type == DB_TYPE_HEAP)
(void) ha_delete_table(entry->db_type,entry->real_name);
/* free blobs */
for (Field **ptr=entry->field ; *ptr ; ptr++)
delete *ptr;
my_free((gptr) entry->record[0],MYF(0));
free_io_cache(entry);
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;
table->file->index_end();
table->file->rnd_init();
if (table->no_rows)
{
new_table.file->extra(HA_EXTRA_NO_ROWS);
new_table.no_rows=1;
}
/* 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->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->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");
join->procedure=procedure;
/*
Tell the client how many fields there are in a row
*/
if (!table)
join->result->send_fields(*fields,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;
table->file->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;
}
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)
{
if (!join->select_lex->dependent ||
((!join->conds || join->conds->val_int()) &&
(!join->having || join->having->val_int())))
{
if (!(error=(*end_select)(join,join_tab,0)) || error == -3)
error=(*end_select)(join,join_tab,1);
}
}
else
{
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_free(join, 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;
if ((tmp=table->file->extra(HA_EXTRA_NO_CACHE)))
{
DBUG_PRINT("error",("extra(HA_EXTRA_NO_CACHE) failed"));
my_errno= tmp;
error= -1;
}
if ((tmp=table->file->index_end()))
{
DBUG_PRINT("error",("index_end() failed"));
my_errno= tmp;
error= -1;
}
if (error == -1)
table->file->print_error(my_errno,MYF(0));
}
#ifndef DBUG_OFF
if (error)
{
DBUG_PRINT("error",("Error: do_select() failed"));
}
#endif
DBUG_RETURN(error || join->thd->net.report_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;
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;
do
{
if (join->thd->killed) // Aborted by user
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
return -2; /* purecov: inspected */
}
join->examined_rows++;
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
info->file->unlock_row();
}
} while (!(error=info->read_record(info)));
}
if (error > 0) // Fatal error
return -1;
if (!found && on_expr)
{ // OUTER JOIN
restore_record(join_tab->table,2); // 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 skipp_last)
{
int error;
READ_RECORD *info;
if (!join_tab->cache.records)
return 0; /* Nothing to do */
if (skipp_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(&join_tab->cache);
join_tab->cache.records=0; join_tab->cache.ptr_record= (uint) ~0;
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->skipp_record()))
{
uint i;
reset_cache(&join_tab->cache);
for (i=(join_tab->cache.records- (skipp_last ? 1 : 0)) ; i-- > 0 ;)
{
read_cached_record(join_tab);
if (!select || !select->skipp_record())
if ((error=(join_tab->next_select)(join,join_tab+1,0)) < 0)
return error; /* purecov: inspected */
}
}
} while (!(error=info->read_record(info)));
if (skipp_last)
read_cached_record(join_tab); // Restore current record
reset_cache(&join_tab->cache);
join_tab->cache.records=0; join_tab->cache.ptr_record= (uint) ~0;
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
*****************************************************************************/
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 ((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 (tab->on_expr && !table->null_row)
{
if ((table->null_row= test(tab->on_expr->val_int() == 0)))
empty_record(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)
{
table->file->print_error(error,MYF(0));
return 1;
}
table->null_row=1; // This is ok.
empty_record(table); // Make empty record
return -1;
}
store_record(table,1);
}
else if (!table->status) // Only happens with left join
restore_record(table,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->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)
{
table->null_row=1;
empty_record(table);
if (error != HA_ERR_KEY_NOT_FOUND)
{
/* 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("read_const: Got error %d when reading table %s",
error, table->path);
table->file->print_error(error,MYF(0));
return 1;
}
return -1;
}
store_record(table,1);
}
else if (!(table->status & ~STATUS_NULL_ROW)) // Only happens with left join
{
table->status=0;
restore_record(table,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 (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)
{
sql_print_error("read_key: Got error %d when reading table '%s'",error,
table->path);
table->file->print_error(error,MYF(0));
return 1;
}
}
table->null_row=0;
return table->status ? -1 : 0;
}
static int
join_read_always_key(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;
if (cp_buffer_from_ref(&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)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("read_const: Got error %d when reading table %s",error,
table->path);
table->file->print_error(error,MYF(0));
return 1;
}
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 (cp_buffer_from_ref(&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)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("read_const: Got error %d when reading table %s",error,
table->path);
table->file->print_error(error,MYF(0));
return 1;
}
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)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("read_next: Got error %d when reading table %s",error,
table->path);
table->file->print_error(error,MYF(0));
return 1;
}
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])))
{
if (error != HA_ERR_END_OF_FILE)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("read_next: Got error %d when reading table %s",error,
table->path);
table->file->print_error(error,MYF(0));
error= 1;
}
else
{
table->status= STATUS_GARBAGE;
error= -1;
}
}
else if (key_cmp(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->keys,(table_map) 0,HA_POS_ERROR);
}
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 & ((key_map) 1 << 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];
error=tab->table->file->index_first(tab->table->record[0]);
if (error)
{
if (error != HA_ERR_KEY_NOT_FOUND && error != HA_ERR_END_OF_FILE)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("read_first_with_key: Got error %d when reading table",
error);
table->file->print_error(error,MYF(0));
return 1;
}
return -1;
}
return 0;
}
static int
join_read_next(READ_RECORD *info)
{
int error=info->file->index_next(info->record);
if (error)
{
if (error != HA_ERR_END_OF_FILE)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error(
"read_next_with_key: Got error %d when reading table %s",
error, info->table->path);
info->file->print_error(error,MYF(0));
return 1;
}
return -1;
}
return 0;
}
static int
join_read_last(JOIN_TAB *tab)
{
TABLE *table=tab->table;
int error;
if (!table->key_read && (table->used_keys & ((key_map) 1 << 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];
error=tab->table->file->index_last(tab->table->record[0]);
if (error)
{
if (error != HA_ERR_END_OF_FILE)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("read_last_with_key: Got error %d when reading table",
error, table->path);
table->file->print_error(error,MYF(0));
return 1;
}
return -1;
}
return 0;
}
static int
join_read_prev(READ_RECORD *info)
{
int error=info->file->index_prev(info->record);
if (error)
{
if (error != HA_ERR_END_OF_FILE)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error(
"read_prev_with_key: Got error %d when reading table: %s",
error,info->table->path);
info->file->print_error(error,MYF(0));
return 1;
}
return -1;
}
return 0;
}
static int
join_ft_read_first(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;
#if NOT_USED_YET
if (cp_buffer_from_ref(&tab->ref)) // as ft-key doesn't use store_key's
return -1; // see also FT_SELECT::init()
#endif
table->file->ft_init();
error=table->file->ft_read(table->record[0]);
if (error)
{
if (error != HA_ERR_END_OF_FILE)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("ft_read_first: Got error %d when reading table %s",
error, table->path);
table->file->print_error(error,MYF(0));
return 1;
}
return -1;
}
return 0;
}
static int
join_ft_read_next(READ_RECORD *info)
{
int error=info->file->ft_read(info->table->record[0]);
if (error)
{
if (error != HA_ERR_END_OF_FILE)
{
if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
sql_print_error("ft_read_next: Got error %d when reading table %s",
error, info->table->path);
info->file->print_error(error,MYF(0));
return 1;
}
return -1;
}
return 0;
}
/*****************************************************************************
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->fields);
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))
{
/* Join over all rows in table; Return number of found rows */
TABLE *table=jt->table;
join->select_options ^= OPTION_FOUND_ROWS;
if (table->record_pointers ||
(table->io_cache && my_b_inited(table->io_cache)))
{
/* Using filesort */
join->send_records= table->found_records;
}
else
{
table->file->info(HA_STATUS_VARIABLE);
join->send_records = table->file->records;
}
}
else
{
join->do_send_rows= 0;
join->unit->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;
if (end_of_records && join->procedure->end_of_records())
error= 1; // Fatal error
}
else
{
if (!join->first_record)
{
/* No matching rows for group function */
clear_tables(join);
copy_fields(&join->tmp_table_param);
}
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;
}
if (error > 0)
DBUG_RETURN(-1); /* purecov: inspected */
if (end_of_records)
{
join->send_records++;
DBUG_RETURN(0);
}
if (!error && ++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);
init_sum_functions(join->sum_funcs);
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->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;
}
// table->file->index_init(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,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->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,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();
if (idx < (int) join->send_group_parts)
{
if (!join->first_record)
{
/* No matching rows for group function */
clear_tables(join);
copy_fields(&join->tmp_table_param);
}
copy_sum_funcs(join->sum_funcs);
if (!join->having || join->having->val_int())
{
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
}
else
join->send_records++;
}
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);
init_sum_functions(join->sum_funcs);
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
*/
if (field->binary() &&
(field->type() != FIELD_TYPE_FLOAT || field->decimals() == 0))
{
return !store_val_in_field(field,right_item);
}
}
}
}
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:
new_cond->used_tables_cache=((Item_cond*) 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);
}
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))
return table->reginfo.join_tab->ref.items[part];
}
return (Item*) 0;
}
/*****************************************************************************
Test if one can use the key to resolve ORDER BY
Returns: 1 if key is ok.
0 if key can't be used
-1 if reverse key can be used
used_key_parts is set to key parts used if length != 0
*****************************************************************************/
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;
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()
*/
while (const_key_parts & 1)
{
key_part++; const_key_parts>>=1;
}
if (key_part == key_part_end || key_part->field != field)
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)
return 0;
reverse=flag; // Remember if reverse
key_part++;
}
*used_key_parts= (uint) (key_part - table->key_info[idx].key_part);
return reverse;
}
static uint find_shortest_key(TABLE *table, key_map usable_keys)
{
uint min_length= (uint) ~0;
uint best= MAX_KEY;
for (uint nr=0; usable_keys ; usable_keys>>=1, nr++)
{
if (usable_keys & 1)
{
if (table->key_info[nr].key_length < min_length)
{
min_length=table->key_info[nr].key_length;
best=nr;
}
}
}
return best;
}
/*
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
DESCRIPTION
Test if a second key is the subkey of the first one.
NOTE
Second key MUST be shorter than the first one.
RETURN
1 - is the subkey
0 - otherwise
*/
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;
}
/*
SYNOPSIS
test_if_subkey()
ref - number of key, used for WHERE clause
usable_keys - keys for testing
DESCRIPTION
Test if we can use one of the 'usable_keys' instead of 'ref' key.
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, 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;
uint ref_key_parts= table->key_info[ref].key_parts;
KEY_PART_INFO *ref_key_part_end= ref_key_part + ref_key_parts;
for (nr= 0; usable_keys; usable_keys>>= 1, nr++)
{
if ((usable_keys & 1) &&
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;
}
/*
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;
TABLE *table=tab->table;
SQL_SELECT *select=tab->select;
key_map usable_keys;
DBUG_ENTER("test_if_skip_sort_order");
/* Check which keys can be used to resolve ORDER BY */
usable_keys= ~(key_map) 0;
for (ORDER *tmp_order=order; tmp_order ; tmp_order=tmp_order->next)
{
if ((*tmp_order->item)->type() != Item::FIELD_ITEM)
{
usable_keys=0;
break;
}
usable_keys&=((Item_field*) (*tmp_order->item))->field->part_of_sortkey;
}
ref_key= -1;
if (tab->ref.key >= 0) // Constant range in WHERE
ref_key=tab->ref.key;
else if (select && select->quick) // Range found by opt_range
ref_key=select->quick->index;
if (ref_key >= 0)
{
/*
We come here when there is a REF key.
*/
int order_direction;
uint used_key_parts;
if (!(usable_keys & ((key_map) 1 << ref_key)))
{
/*
We come here when ref_key is not among usable_keys
*/
uint a;
if ((a= test_if_subkey(order, table, ref_key, usable_keys)) < MAX_KEY)
{
if (tab->ref.key >= 0)
{
tab->ref.key= a;
table->file->index_init(a);
}
else
{
select->quick->index= a;
select->quick->init();
}
ref_key= a;
}
}
/* Check if we get the rows in requested sorted order by using the key */
if ((usable_keys & ((key_map) 1 << 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.
*/
if (table->file->index_flags(ref_key) & HA_NOT_READ_PREFIX_LAST)
DBUG_RETURN(0); // Use filesort
tab->read_first_record= join_read_last_key;
tab->read_record.read_record= join_read_prev_same;
/* fall through */
}
}
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=usable_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->used_keys | table->file->keys_to_use_for_scanning());
for (nr=0; keys ; keys>>=1, nr++)
{
uint not_used;
if (keys & 1)
{
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);
table->file->index_init(nr);
tab->type=JT_NEXT; // Read with index_first(), index_next()
if (table->used_keys & ((key_map) 1 << 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_TAB *tab, ORDER *order,
ha_rows filesort_limit, ha_rows select_limit)
{
SORT_FIELD *sortorder;
uint length;
ha_rows examined_rows;
TABLE *table=tab->table;
SQL_SELECT *select=tab->select;
DBUG_ENTER("create_sort_index");
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->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.
*/
if (!(select->quick=get_ft_or_quick_select_for_ref(table, tab)))
goto err;
}
}
if (table->tmp_table)
table->file->info(HA_STATUS_VARIABLE); // Get record count
table->found_records=filesort(thd, table,sortorder, length,
select, filesort_limit, &examined_rows);
tab->records=table->found_records; // For SQL_CALC_ROWS
delete select; // 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->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)))
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->tmp_table_field() && ! item->const_item())
field_count++;
}
if (!field_count)
{ // only const items
join->unit->select_limit_cnt= 1; // Only send first row
DBUG_RETURN(0);
}
Field **first_field=entry->field+entry->fields - field_count;
offset=entry->field[entry->fields - field_count]->offset();
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) +sizeof(HASH_LINK)) * 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->rnd_init();
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);
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);
}
{
Field **ptr;
for (ptr= first_field, field_length=field_lengths ; *ptr ; ptr++)
(*field_length++)= (*ptr)->pack_length();
}
file->rnd_init();
key_pos=key_buffer;
for (;;)
{
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 */
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,key_pos-key_length,key_length))
{
/* Duplicated found ; Remove the row */
if ((error=file->delete_row(record)))
goto err;
}
else
(void) hash_insert(&hash, key_pos-key_length);
key_pos+=extra_length;
}
my_free((char*) key_buffer,MYF(0));
hash_free(&hash);
file->extra(HA_EXTRA_NO_CACHE);
(void) file->rnd_end();
DBUG_RETURN(0);
err:
my_free((char*) key_buffer,MYF(0));
hash_free(&hash);
file->extra(HA_EXTRA_NO_CACHE);
(void) file->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])->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->records=0; cache->ptr_record= (uint) ~0;
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(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)
{
ulong 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+1,str,length);
*pos=(uchar) length;
pos+=length+1;
}
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(JOIN_CACHE *cache)
{
cache->record_nr=0;
cache->pos=cache->buff;
}
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)
{
memcpy(copy->str,pos+1,length=(uint) *pos);
memset(copy->str+length,' ',copy->length-length);
pos+=1+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->ref)) || diff)
return 1;
return memcmp(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length)
!= 0;
}
bool
cp_buffer_from_ref(TABLE_REF *ref)
{
for (store_key **copy=ref->key_copy ; *copy ; copy++)
if ((*copy)->copy())
return 1; // Something went wrong
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 *itemptr=*order->item;
if (itemptr->type() == Item::INT_ITEM)
{ /* Order by position */
Item *item=0;
uint count= (uint) ((Item_int*)itemptr)->value;
if (!count || count > fields.elements)
{
my_printf_error(ER_BAD_FIELD_ERROR,ER(ER_BAD_FIELD_ERROR),
MYF(0),itemptr->full_name(),
thd->where);
return 1;
}
order->item= ref_pointer_array + count-1;
order->in_field_list= 1;
return 0;
}
uint counter;
Item **item= find_item_in_list(itemptr, fields, &counter, IGNORE_ERRORS);
if (item)
{
order->item= ref_pointer_array + counter;
order->in_field_list=1;
return 0;
}
order->in_field_list=0;
Item *it= *order->item;
if (it->fix_fields(thd, tables, order->item) || it->check_cols(1) ||
thd->is_fatal_error)
return 1; // Wrong field
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;
}
/*
Allocate array of references to address all_fileds list elements
*/
int setup_ref_array(THD* thd, Item ***rref_pointer_array, uint elements)
{
if (*rref_pointer_array)
return 0;
return (*rref_pointer_array=
(Item **)thd->alloc(sizeof(Item*) * elements * 5)) == 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;
}
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)
{
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;
for (; new_field ; new_field= new_field->next)
{
if ((item= find_item_in_list(*new_field->item, fields, &counter,
IGNORE_ERRORS)))
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, ORDER *order_list, List<Item> &fields,
bool *all_order_by_fields_used)
{
List_iterator<Item> li(fields);
Item *item;
ORDER *order,*group,**prev;
*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)
continue;
if (!item->marker)
{
ORDER *ord=(ORDER*) thd->calloc(sizeof(ORDER));
if (!ord)
return 0;
ord->item=li.ref();
ord->asc=1;
*prev=ord;
prev= &ord->next;
}
}
*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))
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)->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;
}
/*
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(*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)
{
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;
}
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;
DBUG_ENTER("setup_copy_fields");
res_selected_fields.empty();
res_all_fields.empty();
List_iterator_fast<Item> itr(res_all_fields);
uint i, border= all_fields.elements - elements;
if (!(copy=param->copy_field= new Copy_field[param->field_count]))
goto err2;
param->copy_funcs.empty();
for (i= 0; (pos= li++); i++)
{
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;
if (param->copy_funcs.push_back(pos))
goto err;
}
else
{
/*
set up save buffer and change result_field to point at
saved value
*/
Field *field= item->field;
item->result_field=field->new_field(&thd->mem_root,field->table);
char *tmp=(char*) sql_alloc(field->pack_length()+1);
if (!tmp)
goto err;
copy->set(tmp, item->result_field);
item->result_field->move_field(copy->to_ptr,copy->to_null_ptr,1);
copy++;
}
}
else if ((pos->type() == Item::FUNC_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 (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);
DBUG_RETURN(0);
err:
delete [] param->copy_field; // This is never 0
param->copy_field=0;
err2:
DBUG_RETURN(TRUE);
}
/*
Copy fields and null values between two tables
*/
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_it;
it.rewind();
Item_copy_string *item;
while ((item = (Item_copy_string*) it++))
item->copy();
}
/*****************************************************************************
Make an array of pointer to sum_functions to speed up sum_func calculation
*****************************************************************************/
static bool
make_sum_func_list(JOIN *join,List<Item> &fields)
{
DBUG_ENTER("make_sum_func_list");
Item_sum **func =
(Item_sum**) sql_alloc(sizeof(Item_sum*)*
(join->tmp_table_param.sum_func_count+1));
if (!func)
DBUG_RETURN(TRUE);
List_iterator<Item> it(fields);
join->sum_funcs=func;
Item *field;
while ((field=it++))
{
if (field->type() == Item::SUM_FUNC_ITEM && !field->const_item())
{
*func++=(Item_sum*) field;
/* let COUNT(DISTINCT) create the temporary table */
if (((Item_sum*) field)->setup(join->thd))
DBUG_RETURN(TRUE);
}
}
*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->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
!=0 - 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(0);
}
/* Copy result of sum functions to record in tmp_table */
static void
copy_sum_funcs(Item_sum **func_ptr)
{
Item_sum *func;
for (; (func = *func_ptr) ; func_ptr++)
(void) func->save_in_result_field(1);
return;
}
static void
init_sum_functions(Item_sum **func_ptr)
{
Item_sum *func;
for (; (func= (Item_sum*) *func_ptr) ; func_ptr++)
func->reset();
}
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);
/*
Here we pass 0 as the first argument to fix_fields that don't need
to do any stack checking (This is already done in the initial fix_fields).
*/
cond->fix_fields((THD *) 0,(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);
}
/****************************************************************************
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_LEX *select_lex = &(join->thd->lex.select_lex);
select_result *result=join->result;
Item *item_null= new Item_null();
CHARSET_INFO *cs= &my_charset_latin1;
DBUG_ENTER("select_describe");
DBUG_PRINT("info", ("Select 0x%lx, type %s, message %s",
(ulong)join->select_lex, join->select_lex->type,
message));
/* Don't log this into the slow query log */
select_lex->options&= ~(QUERY_NO_INDEX_USED | 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
{
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];
String tmp1(buff1,sizeof(buff1),cs);
String tmp2(buff2,sizeof(buff2),cs);
tmp1.length(0);
tmp2.length(0);
item_list.empty();
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));
if (tab->type == JT_ALL && tab->select && tab->select->quick)
tab->type= JT_RANGE;
if (table->tmp_table == TMP_TABLE && table->derived_select_number != 0)
{
// Derived table name generation
char buff[512];
int len= my_snprintf(buff, 512, "<derived%u>",
table->derived_select_number);
item_list.push_back(new Item_string(buff, len, cs));
}
else
item_list.push_back(new Item_string(table->table_name,
strlen(table->table_name),
cs));
item_list.push_back(new Item_string(join_type_str[tab->type],
strlen(join_type_str[tab->type]),
cs));
key_map bits;
uint j;
for (j=0,bits=tab->keys ; bits ; j++,bits>>=1)
{
if (bits & 1)
{
if (tmp1.length())
tmp1.append(',');
tmp1.append(table->key_info[j].name);
}
}
if (tmp1.length())
item_list.push_back(new Item_string(tmp1.ptr(),tmp1.length(),cs));
else
item_list.push_back(item_null);
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());
}
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);
}
item_list.push_back(new Item_int((longlong) (ulonglong)
join->best_positions[i]. records_read,
21));
my_bool key_read=table->key_read;
if (tab->type == JT_NEXT &&
((table->used_keys & ((key_map) 1 << 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)
{
sprintf(buff_ptr,"; Range checked for each record (index map: %u)",
tab->keys);
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())
{
res= mysql_explain_select(thd, sl,
(((&thd->lex.select_lex)==sl)?
((thd->lex.all_selects_list != sl)?"PRIMARY":
"SIMPLE"):
((sl == first)?
((sl->linkage == DERIVED_TABLE_TYPE) ?
"DERIVED":
((sl->dependent)?"DEPENDENT SUBQUERY":
(sl->uncacheable?"UNCACHEABLE SUBQUERY":
"SUBQUERY"))):
((sl->dependent)?"DEPENDENT UNION":
sl->uncacheable?"UNCACHEABLE UNION":
"UNION"))),
result);
if (res)
break;
}
if (res > 0 || thd->net.report_error)
res= -1; // mysql_explain_select do not report error
DBUG_RETURN(res);
}
int mysql_explain_select(THD *thd, SELECT_LEX *select_lex, char const *type,
select_result *result)
{
DBUG_ENTER("mysql_explain_select");
DBUG_PRINT("info", ("Select 0x%lx, type %s", (ulong)select_lex, type))
select_lex->type= type;
thd->lex.current_select= select_lex;
SELECT_LEX_UNIT *unit= select_lex->master_unit();
int 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*) thd->lex.proc_list.first,
select_lex->options | thd->options | SELECT_DESCRIBE,
result, unit, select_lex, 0);
DBUG_RETURN(res);
}
/*
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();
}
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