database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

MWL#17: Table elimination

Browse Source 
- Moved table elimination code to sql/opt_table_elimination.cc
- Added comments 

.bzrignore:
  MWL#17: Table elimination
  - Moved table elimination code to sql/opt_table_elimination.cc
libmysqld/Makefile.am:
  MWL#17: Table elimination
  - Moved table elimination code to sql/opt_table_elimination.cc
sql/CMakeLists.txt:
  MWL#17: Table elimination
  - Moved table elimination code to sql/opt_table_elimination.cc
sql/Makefile.am:
  MWL#17: Table elimination
  - Moved table elimination code to sql/opt_table_elimination.cc
This commit is contained in:
Sergey Petrunia
2009-06-25 14:05:53 +04:00
parent defbdce7e8
commit 4102605fba
11 changed files with 548 additions and 404 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
sql/sql_select.h
View File

@ -28,6 +28,11 @@
#include "procedure.h"
#include <myisam.h>
#define FT_KEYPART (MAX_REF_PARTS+10)
/* Values in optimize */
#define KEY_OPTIMIZE_EXISTS 1
#define KEY_OPTIMIZE_REF_OR_NULL 2
typedef struct keyuse_t {
TABLE *table;
Item *val; /**< or value if no field */
@ -51,6 +56,14 @@ typedef struct keyuse_t {
NULL - Otherwise (the source equality can't be turned off)
*/
bool *cond_guard;
/*
TRUE <=> This keyuse can be used to construct key access.
FALSE <=> Otherwise. Currently unusable KEYUSEs represent equalities
where one table column refers to another one, like this:
t.keyXpartA=func(t.keyXpartB)
This equality cannot be used for index access but is useful
for table elimination.
*/
bool usable;
} KEYUSE;
@ -734,9 +747,13 @@ bool error_if_full_join(JOIN *join);
int report_error(TABLE *table, int error);
int safe_index_read(JOIN_TAB *tab);
COND *remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value);
void set_position(JOIN *join,uint idx,JOIN_TAB *table,KEYUSE *key);
inline bool optimizer_flag(THD *thd, uint flag)
{
return (thd->variables.optimizer_switch & flag);
}
void eliminate_tables(JOIN *join, uint *const_tbl_count,
table_map *const_tables);