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mariadb/sql/sql_select.h
serg@serg.mylan 01b3c70926 renamed: 
Item_buff -> Cached_item
  Item_arena -> Query_arena
  TEST_ASSERT -> YYERROR_UNLESS
2005-06-15 19:58:35 +02:00

543 lines
17 KiB
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/* Copyright (C) 2000 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 */
/* classes to use when handling where clause */
#ifdef USE_PRAGMA_INTERFACE
#pragma interface /* gcc class implementation */
#endif
#include "procedure.h"
#include <myisam.h>
typedef struct keyuse_t {
TABLE *table;
Item *val; /* or value if no field */
table_map used_tables;
uint key, keypart, optimize;
key_part_map keypart_map;
ha_rows ref_table_rows;
/*
If true, the comparison this value was created from will not be
satisfied if val has NULL 'value'.
*/
bool null_rejecting;
} KEYUSE;
class store_key;
typedef struct st_table_ref
{
bool key_err;
uint key_parts; // num of ...
uint key_length; // length of key_buff
int key; // key no
byte *key_buff; // value to look for with key
byte *key_buff2; // key_buff+key_length
store_key **key_copy; //
Item **items; // val()'s for each keypart
/*
(null_rejecting & (1<<i)) means the condition is '=' and no matching
rows will be produced if items[i] IS NULL (see add_not_null_conds())
*/
key_part_map null_rejecting;
table_map depend_map; // Table depends on these tables.
byte *null_ref_key; // null byte position in the key_buf.
// used for REF_OR_NULL optimization.
} TABLE_REF;
/*
** CACHE_FIELD and JOIN_CACHE is used on full join to cache records in outer
** table
*/
typedef struct st_cache_field {
char *str;
uint length,blob_length;
Field_blob *blob_field;
bool strip;
} CACHE_FIELD;
typedef struct st_join_cache {
uchar *buff,*pos,*end;
uint records,record_nr,ptr_record,fields,length,blobs;
CACHE_FIELD *field,**blob_ptr;
SQL_SELECT *select;
} JOIN_CACHE;
/*
** The structs which holds the join connections and join states
*/
enum join_type { JT_UNKNOWN,JT_SYSTEM,JT_CONST,JT_EQ_REF,JT_REF,JT_MAYBE_REF,
JT_ALL, JT_RANGE, JT_NEXT, JT_FT, JT_REF_OR_NULL,
JT_UNIQUE_SUBQUERY, JT_INDEX_SUBQUERY, JT_INDEX_MERGE};
class JOIN;
enum enum_nested_loop_state
{
NESTED_LOOP_KILLED= -2, NESTED_LOOP_ERROR= -1,
NESTED_LOOP_OK= 0, NESTED_LOOP_NO_MORE_ROWS= 1,
NESTED_LOOP_QUERY_LIMIT= 3, NESTED_LOOP_CURSOR_LIMIT= 4
};
typedef enum_nested_loop_state
(*Next_select_func)(JOIN *, struct st_join_table *, bool);
typedef int (*Read_record_func)(struct st_join_table *tab);
typedef struct st_join_table {
TABLE *table;
KEYUSE *keyuse; /* pointer to first used key */
SQL_SELECT *select;
COND *select_cond;
QUICK_SELECT_I *quick;
Item **on_expr_ref; /* pointer to the associated on expression */
COND_EQUAL *cond_equal; /* multiple equalities for the on expression */
st_join_table *first_inner; /* first inner table for including outerjoin */
bool found; /* true after all matches or null complement */
bool not_null_compl;/* true before null complement is added */
st_join_table *last_inner; /* last table table for embedding outer join */
st_join_table *first_upper; /* first inner table for embedding outer join */
st_join_table *first_unmatched; /* used for optimization purposes only */
const char *info;
Read_record_func read_first_record;
Next_select_func next_select;
READ_RECORD read_record;
double worst_seeks;
key_map const_keys; /* Keys with constant part */
key_map checked_keys; /* Keys checked in find_best */
key_map needed_reg;
key_map keys; /* all keys with can be used */
ha_rows records,found_records,read_time;
table_map dependent,key_dependent;
uint use_quick,index;
uint status; // Save status for cache
uint used_fields,used_fieldlength,used_blobs;
enum join_type type;
bool cached_eq_ref_table,eq_ref_table,not_used_in_distinct;
TABLE_REF ref;
JOIN_CACHE cache;
JOIN *join;
void cleanup();
} JOIN_TAB;
typedef struct st_position /* Used in find_best */
{
double records_read;
double read_time;
JOIN_TAB *table;
KEYUSE *key;
} POSITION;
typedef struct st_rollup
{
enum State { STATE_NONE, STATE_INITED, STATE_READY };
State state;
Item_null_result **null_items;
Item ***ref_pointer_arrays;
List<Item> *fields;
} ROLLUP;
class JOIN :public Sql_alloc
{
public:
JOIN_TAB *join_tab,**best_ref;
JOIN_TAB **map2table; // mapping between table indexes and JOIN_TABs
JOIN_TAB *join_tab_save; // saved join_tab for subquery reexecution
TABLE **table,**all_tables,*sort_by_table;
uint tables,const_tables;
uint send_group_parts;
bool sort_and_group,first_record,full_join,group, no_field_update;
bool do_send_rows;
/*
TRUE when we want to resume nested loop iterations when
fetching data from a cursor
*/
bool resume_nested_loop;
table_map const_table_map,found_const_table_map,outer_join;
ha_rows send_records,found_records,examined_rows,row_limit, select_limit;
/*
Used to fetch no more than given amount of rows per one
fetch operation of server side cursor.
The value is checked in end_send and end_send_group in fashion, similar
to offset_limit_cnt:
- fetch_limit= HA_POS_ERROR if there is no cursor.
- when we open a cursor, we set fetch_limit to 0,
- on each fetch iteration we add num_rows to fetch to fetch_limit
*/
ha_rows fetch_limit;
POSITION positions[MAX_TABLES+1],best_positions[MAX_TABLES+1];
double best_read;
List<Item> *fields;
List<Cached_item> group_fields, group_fields_cache;
TABLE *tmp_table;
// used to store 2 possible tmp table of SELECT
TABLE *exec_tmp_table1, *exec_tmp_table2;
THD *thd;
Item_sum **sum_funcs, ***sum_funcs_end;
/* second copy of sumfuncs (for queries with 2 temporary tables */
Item_sum **sum_funcs2, ***sum_funcs_end2;
Procedure *procedure;
Item *having;
Item *tmp_having; // To store having when processed temporary table
Item *having_history; // Store having for explain
uint select_options;
select_result *result;
TMP_TABLE_PARAM tmp_table_param;
MYSQL_LOCK *lock;
// unit structure (with global parameters) for this select
SELECT_LEX_UNIT *unit;
// select that processed
SELECT_LEX *select_lex;
JOIN *tmp_join; // copy of this JOIN to be used with temporary tables
ROLLUP rollup; // Used with rollup
bool select_distinct; // Set if SELECT DISTINCT
/*
simple_xxxxx is set if ORDER/GROUP BY doesn't include any references
to other tables than the first non-constant table in the JOIN.
It's also set if ORDER/GROUP BY is empty.
*/
bool simple_order, simple_group;
/*
Is set only in case if we have a GROUP BY clause
and no ORDER BY after constant elimination of 'order'.
*/
bool no_order;
/* Is set if we have a GROUP BY and we have ORDER BY on a constant. */
bool skip_sort_order;
bool need_tmp, hidden_group_fields, buffer_result;
DYNAMIC_ARRAY keyuse;
Item::cond_result cond_value;
List<Item> all_fields; // to store all fields that used in query
//Above list changed to use temporary table
List<Item> tmp_all_fields1, tmp_all_fields2, tmp_all_fields3;
//Part, shared with list above, emulate following list
List<Item> tmp_fields_list1, tmp_fields_list2, tmp_fields_list3;
List<Item> &fields_list; // hold field list passed to mysql_select
int error;
ORDER *order, *group_list, *proc_param; //hold parameters of mysql_select
COND *conds; // ---"---
Item *conds_history; // store WHERE for explain
TABLE_LIST *tables_list; //hold 'tables' parameter of mysql_select
List<TABLE_LIST> *join_list; // list of joined tables in reverse order
COND_EQUAL *cond_equal;
SQL_SELECT *select; //created in optimisation phase
JOIN_TAB *return_tab; //used only for outer joins
Item **ref_pointer_array; //used pointer reference for this select
// Copy of above to be used with different lists
Item **items0, **items1, **items2, **items3, **current_ref_pointer_array;
uint ref_pointer_array_size; // size of above in bytes
const char *zero_result_cause; // not 0 if exec must return zero result
bool union_part; // this subselect is part of union
bool optimized; // flag to avoid double optimization in EXPLAIN
JOIN(THD *thd_arg, List<Item> &fields_arg, ulong select_options_arg,
select_result *result_arg)
:fields_list(fields_arg)
{
init(thd_arg, fields_arg, select_options_arg, result_arg);
}
void init(THD *thd_arg, List<Item> &fields_arg, ulong select_options_arg,
select_result *result_arg)
{
join_tab= join_tab_save= 0;
table= 0;
tables= 0;
const_tables= 0;
join_list= 0;
sort_and_group= 0;
first_record= 0;
do_send_rows= 1;
resume_nested_loop= FALSE;
send_records= 0;
found_records= 0;
fetch_limit= HA_POS_ERROR;
examined_rows= 0;
exec_tmp_table1= 0;
exec_tmp_table2= 0;
thd= thd_arg;
sum_funcs= sum_funcs2= 0;
procedure= 0;
having= tmp_having= having_history= 0;
select_options= select_options_arg;
result= result_arg;
lock= thd_arg->lock;
select_lex= 0; //for safety
tmp_join= 0;
select_distinct= test(select_options & SELECT_DISTINCT);
no_order= 0;
simple_order= 0;
simple_group= 0;
skip_sort_order= 0;
need_tmp= 0;
hidden_group_fields= 0; /*safety*/
buffer_result= test(select_options & OPTION_BUFFER_RESULT) &&
!test(select_options & OPTION_FOUND_ROWS);
error= 0;
select= 0;
return_tab= 0;
ref_pointer_array= items0= items1= items2= items3= 0;
ref_pointer_array_size= 0;
zero_result_cause= 0;
optimized= 0;
cond_equal= 0;
all_fields= fields_arg;
fields_list= fields_arg;
bzero((char*) &keyuse,sizeof(keyuse));
tmp_table_param.copy_field=0;
tmp_table_param.end_write_records= HA_POS_ERROR;
rollup.state= ROLLUP::STATE_NONE;
}
int prepare(Item ***rref_pointer_array, TABLE_LIST *tables, uint wind_num,
COND *conds, uint og_num, ORDER *order, ORDER *group,
Item *having, ORDER *proc_param, SELECT_LEX *select,
SELECT_LEX_UNIT *unit);
int optimize();
int reinit();
void exec();
int cleanup();
void restore_tmp();
bool alloc_func_list();
bool make_sum_func_list(List<Item> &all_fields, List<Item> &send_fields,
bool before_group_by, bool recompute= FALSE);
inline void set_items_ref_array(Item **ptr)
{
memcpy((char*) ref_pointer_array, (char*) ptr, ref_pointer_array_size);
current_ref_pointer_array= ptr;
}
inline void init_items_ref_array()
{
items0= ref_pointer_array + all_fields.elements;
memcpy(items0, ref_pointer_array, ref_pointer_array_size);
current_ref_pointer_array= items0;
}
bool rollup_init();
bool rollup_make_fields(List<Item> &all_fields, List<Item> &fields,
Item_sum ***func);
int rollup_send_data(uint idx);
int rollup_write_data(uint idx, TABLE *table);
bool test_in_subselect(Item **where);
void join_free(bool full);
void clear();
bool save_join_tab();
bool send_row_on_empty_set()
{
return (do_send_rows && tmp_table_param.sum_func_count != 0 &&
!group_list);
}
bool change_result(select_result *result);
};
/*
Server-side cursor (now stands only for basic read-only cursor)
See class implementation in sql_select.cc
A cursor has its own runtime state - list of used items and memory root of
used memory - which is different from Prepared statement runtime: it must
be different at least for the purpose of reusing the same prepared
statement for many cursors.
*/
class Cursor: public Sql_alloc, public Query_arena
{
JOIN *join;
SELECT_LEX_UNIT *unit;
TABLE *open_tables;
MYSQL_LOCK *lock;
TABLE *derived_tables;
/* List of items created during execution */
query_id_t query_id;
public:
select_send result;
/* Temporary implementation as now we replace THD state by value */
/* Save THD state into cursor */
void init_from_thd(THD *thd);
/* bzero cursor state in THD */
void reset_thd(THD *thd);
int open(JOIN *join);
void fetch(ulong num_rows);
void reset() { join= 0; }
bool is_open() const { return join != 0; }
void close();
void set_unit(SELECT_LEX_UNIT *unit_arg) { unit= unit_arg; }
Cursor() :Query_arena(TRUE), join(0), unit(0) {}
~Cursor();
};
typedef struct st_select_check {
uint const_ref,reg_ref;
} SELECT_CHECK;
extern const char *join_type_str[];
void TEST_join(JOIN *join);
/* Extern functions in sql_select.cc */
bool store_val_in_field(Field *field,Item *val);
TABLE *create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
ORDER *group, bool distinct, bool save_sum_fields,
ulong select_options, ha_rows rows_limit,
char* alias);
TABLE *create_virtual_tmp_table(THD *thd, List<create_field> &field_list);
void free_tmp_table(THD *thd, TABLE *entry);
void count_field_types(TMP_TABLE_PARAM *param, List<Item> &fields,
bool reset_with_sum_func);
bool setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
Item **ref_pointer_array,
List<Item> &new_list1, List<Item> &new_list2,
uint elements, List<Item> &fields);
void copy_fields(TMP_TABLE_PARAM *param);
void copy_funcs(Item **func_ptr);
bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
int error, bool ignore_last_dupp_error);
uint find_shortest_key(TABLE *table, const key_map *usable_keys);
Field* create_tmp_field_from_field(THD *thd, Field* org_field,
const char *name, TABLE *table,
Item_field *item, uint convert_blob_length);
/* functions from opt_sum.cc */
bool simple_pred(Item_func *func_item, Item **args, bool *inv_order);
int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds);
/* from sql_delete.cc, used by opt_range.cc */
extern "C" int refpos_order_cmp(void* arg, const void *a,const void *b);
/* class to copying an field/item to a key struct */
class store_key :public Sql_alloc
{
protected:
Field *to_field; // Store data here
char *null_ptr;
char err;
public:
store_key(THD *thd, Field *field_arg, char *ptr, char *null, uint length)
:null_ptr(null),err(0)
{
if (field_arg->type() == FIELD_TYPE_BLOB)
{
/* Key segments are always packed with a 2 byte length prefix */
to_field=new Field_varstring(ptr, length, 2, (uchar*) null, 1,
Field::NONE, field_arg->field_name,
field_arg->table, field_arg->charset());
}
else
to_field=field_arg->new_key_field(thd->mem_root, field_arg->table,
ptr, (uchar*) null, 1);
}
virtual ~store_key() {} /* Not actually needed */
virtual bool copy()=0;
virtual const char *name() const=0;
};
class store_key_field: public store_key
{
Copy_field copy_field;
const char *field_name;
public:
store_key_field(THD *thd, Field *to_field_arg, char *ptr, char *null_ptr_arg,
uint length, Field *from_field, const char *name_arg)
:store_key(thd, to_field_arg,ptr,
null_ptr_arg ? null_ptr_arg : from_field->maybe_null() ? &err
: NullS,length), field_name(name_arg)
{
if (to_field)
{
copy_field.set(to_field,from_field,0);
}
}
bool copy()
{
copy_field.do_copy(&copy_field);
return err != 0;
}
const char *name() const { return field_name; }
};
class store_key_item :public store_key
{
protected:
Item *item;
public:
store_key_item(THD *thd, Field *to_field_arg, char *ptr, char *null_ptr_arg,
uint length, Item *item_arg)
:store_key(thd, to_field_arg,ptr,
null_ptr_arg ? null_ptr_arg : item_arg->maybe_null ?
&err : NullS, length), item(item_arg)
{}
bool copy()
{
return item->save_in_field_no_warnings(to_field, 1) || err != 0;
}
const char *name() const { return "func"; }
};
class store_key_const_item :public store_key_item
{
bool inited;
public:
store_key_const_item(THD *thd, Field *to_field_arg, char *ptr,
char *null_ptr_arg, uint length,
Item *item_arg)
:store_key_item(thd, to_field_arg,ptr,
null_ptr_arg ? null_ptr_arg : item_arg->maybe_null ?
&err : NullS, length, item_arg), inited(0)
{
}
bool copy()
{
if (!inited)
{
inited=1;
if (item->save_in_field(to_field, 1))
err= 1;
}
return err != 0;
}
const char *name() const { return "const"; }
};
bool cp_buffer_from_ref(THD *thd, TABLE_REF *ref);
bool error_if_full_join(JOIN *join);
int report_error(TABLE *table, int error);
int safe_index_read(JOIN_TAB *tab);
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