diff options
Diffstat (limited to 'sql/sql_select.h')
| -rw-r--r-- | sql/sql_select.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/sql/sql_select.h b/sql/sql_select.h index a1e382d1bcd..9bce799b02d 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -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); + |