diff options
Diffstat (limited to 'sql/sql_select.h')
| -rw-r--r-- | sql/sql_select.h | 38 |
1 files changed, 24 insertions, 14 deletions
diff --git a/sql/sql_select.h b/sql/sql_select.h index affa0fd3ed4..76c7715e68f 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -160,7 +160,9 @@ typedef struct st_join_table { TABLE *table; KEYUSE *keyuse; /**< pointer to first used key */ SQL_SELECT *select; - COND *select_cond; + COND *select_cond; + COND *on_precond; /**< part of on condition to check before + accessing the first inner table */ QUICK_SELECT_I *quick; /* The value of select_cond before we've attempted to do Index Condition @@ -1497,24 +1499,31 @@ public: the number of rows in it may vary from one subquery execution to another. */ bool no_const_tables; + /* + This flag is set if we call no_rows_in_result() as par of end_group(). + This is used as a simple speed optimization to avoiding calling + restore_no_rows_in_result() in ::reinit() + */ + bool no_rows_in_result_called; /** Copy of this JOIN to be used with temporary tables. - tmp_join is used when the JOIN needs to be "reusable" (e.g. in a subquery - that gets re-executed several times) and we know will use temporary tables - for materialization. The materialization to a temporary table overwrites the - JOIN structure to point to the temporary table after the materialization is - done. This is where tmp_join is used : it's a copy of the JOIN before the - materialization and is used in restoring before re-execution by overwriting - the current JOIN structure with the saved copy. - Because of this we should pay extra care of not freeing up helper structures - that are referenced by the original contents of the JOIN. We can check for - this by making sure the "current" join is not the temporary copy, e.g. - !tmp_join || tmp_join != join + tmp_join is used when the JOIN needs to be "reusable" (e.g. in a + subquery that gets re-executed several times) and we know will use + temporary tables for materialization. The materialization to a + temporary table overwrites the JOIN structure to point to the + temporary table after the materialization is done. This is where + tmp_join is used : it's a copy of the JOIN before the + materialization and is used in restoring before re-execution by + overwriting the current JOIN structure with the saved copy. + Because of this we should pay extra care of not freeing up helper + structures that are referenced by the original contents of the + JOIN. We can check for this by making sure the "current" join is + not the temporary copy, e.g. !tmp_join || tmp_join != join - We should free these sub-structures at JOIN::destroy() if the "current" join - has a copy is not that copy. + We should free these sub-structures at JOIN::destroy() if the + "current" join has a copy is not that copy. */ JOIN *tmp_join; ROLLUP rollup; ///< Used with rollup @@ -1651,6 +1660,7 @@ public: optimized= 0; cond_equal= 0; group_optimized_away= 0; + no_rows_in_result_called= 0; all_fields= fields_arg; if (&fields_list != &fields_arg) /* Avoid valgrind-warning */ |