diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 71 |
1 files changed, 41 insertions, 30 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index f4fbd03768d..2e1429feb3e 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -91,7 +91,7 @@ static int return_zero_rows(JOIN *join, select_result *res,TABLE_LIST *tables, uint select_options, const char *info, Item *having, Procedure *proc, SELECT_LEX_UNIT *unit); -static COND *build_equal_items(COND *cond, +static COND *build_equal_items(THD *thd, COND *cond, COND_EQUAL *inherited, List<TABLE_LIST> *join_list, COND_EQUAL **cond_equal_ref); @@ -101,6 +101,7 @@ static COND* substitute_for_best_equal_field(COND *cond, static COND *simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top); static COND *optimize_cond(JOIN *join, COND *conds, + List<TABLE_LIST> *join_list, Item::cond_result *cond_value); static bool resolve_nested_join (TABLE_LIST *table); static COND *remove_eq_conds(THD *thd, COND *cond, @@ -228,14 +229,11 @@ int handle_select(THD *thd, LEX *lex, select_result *result) select_lex->options | thd->options, result, unit, select_lex); } - - /* Don't set res if it's -1 as we may want this later */ DBUG_PRINT("info",("res: %d report_error: %d", res, thd->net.report_error)); - if (thd->net.report_error || res<0) + if (thd->net.report_error || res < 0) { - if (res > 0) - result->send_error(0, NullS); + result->send_error(0, NullS); result->abort(); res= 1; // Error sent to client } @@ -556,17 +554,7 @@ JOIN::optimize() thd->restore_backup_item_arena(arena, &backup); } - /* - Build all multiple equality predicates and eliminate equality - predicates that can be inferred from these multiple equalities. - For each reference of a field included into a multiple equality - that occurs in a function set a pointer to the multiple equality - predicate. Substitute a constant instead of this field if the - multiple equality contains a constant. - */ - conds= build_equal_items(conds, NULL, join_list, &cond_equal); - - conds= optimize_cond(this, conds,&cond_value); + conds= optimize_cond(this, conds, join_list, &cond_value); if (thd->net.report_error) { error= 1; @@ -684,6 +672,7 @@ JOIN::optimize() { conds= substitute_for_best_equal_field(conds, cond_equal, map2table); conds->update_used_tables(); + DBUG_EXECUTE("where", print_where(conds, "after substitute_best_equal");); } /* Permorm the the optimization on fields evaluation mentioned above @@ -1723,11 +1712,10 @@ int Cursor::open(JOIN *join_arg) { join= join_arg; - THD *thd= join->thd; - /* First non-constant table */ JOIN_TAB *join_tab= join->join_tab + join->const_tables; + DBUG_ENTER("Cursor::open"); /* Send fields description to the client; server_status is sent @@ -1749,7 +1737,9 @@ Cursor::open(JOIN *join_arg) join->fetch_limit= join->unit->offset_limit_cnt; /* Disable JOIN CACHE as it is not working with cursors yet */ - for (JOIN_TAB *tab= join_tab; tab != join->join_tab + join->tables - 1; ++tab) + for (JOIN_TAB *tab= join_tab; + tab != join->join_tab + join->tables - 1; + tab++) { if (tab->next_select == sub_select_cache) tab->next_select= sub_select; @@ -1763,7 +1753,7 @@ Cursor::open(JOIN *join_arg) */ DBUG_ASSERT(join_tab->table->null_row == 0); - return join_tab->read_first_record(join_tab); + DBUG_RETURN(join_tab->read_first_record(join_tab)); } @@ -6028,7 +6018,7 @@ template class List_iterator<Item_func_match>; find_item_equal() cond_equal multiple equalities to search in field field to look for - inherited_fl :out set up to TRUE iff multiple equality is found + inherited_fl :out set up to TRUE if multiple equality is found on upper levels (not on current level of cond_equal) DESCRIPTION @@ -6446,12 +6436,14 @@ static COND *build_equal_items_for_cond(COND *cond, return cond; } + /* Build multiple equalities for a condition and all on expressions that inherit these multiple equalities SYNOPSIS build_equal_items() + thd Thread handler cond condition to build the multiple equalities for inherited path to all inherited multiple equality items join_list list of join tables to which the condition refers to @@ -6503,7 +6495,7 @@ static COND *build_equal_items_for_cond(COND *cond, pointer to the transformed condition containing multiple equalities */ -static COND *build_equal_items(COND *cond, +static COND *build_equal_items(THD *thd, COND *cond, COND_EQUAL *inherited, List<TABLE_LIST> *join_list, COND_EQUAL **cond_equal_ref) @@ -6540,12 +6532,13 @@ static COND *build_equal_items(COND *cond, { if (table->on_expr) { + Item *expr; List<TABLE_LIST> *join_list= table->nested_join ? &table->nested_join->join_list : NULL; - table->on_expr= build_equal_items(table->on_expr, - inherited, - join_list, - &table->cond_equal); + expr= build_equal_items(thd, table->on_expr, inherited, join_list, + &table->cond_equal); + if (expr != table->on_expr) + thd->change_item_tree(&table->on_expr, expr); } } } @@ -6553,6 +6546,7 @@ static COND *build_equal_items(COND *cond, return cond; } + /* Compare field items by table order in the execution plan @@ -6797,6 +6791,7 @@ static COND* substitute_for_best_equal_field(COND *cond, return cond; } + /* change field = field to field = const for each found field = const in the and_level @@ -7089,6 +7084,7 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top) */ if (table->on_expr) { + Item *expr; /* If an on expression E is attached to the table, check all null rejected predicates in this expression. @@ -7097,8 +7093,9 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top) the outer join is converted to an inner join and the corresponding on expression is added to E. */ - table->on_expr= simplify_joins(join, &nested_join->join_list, - table->on_expr, FALSE); + expr= simplify_joins(join, &nested_join->join_list, + table->on_expr, FALSE); + table->on_expr= expr; } nested_join->used_tables= (table_map) 0; nested_join->not_null_tables=(table_map) 0; @@ -7207,8 +7204,10 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top) DBUG_RETURN(conds); } + static COND * -optimize_cond(JOIN *join, COND *conds, Item::cond_result *cond_value) +optimize_cond(JOIN *join, COND *conds, List<TABLE_LIST> *join_list, + Item::cond_result *cond_value) { THD *thd= join->thd; SELECT_LEX *select= thd->lex->current_select; @@ -7221,7 +7220,19 @@ optimize_cond(JOIN *join, COND *conds, Item::cond_result *cond_value) } else { + /* + Build all multiple equality predicates and eliminate equality + predicates that can be inferred from these multiple equalities. + For each reference of a field included into a multiple equality + that occurs in a function set a pointer to the multiple equality + predicate. Substitute a constant instead of this field if the + multiple equality contains a constant. + */ DBUG_EXECUTE("where", print_where(conds, "original");); + conds= build_equal_items(join->thd, conds, NULL, join_list, + &join->cond_equal); + DBUG_EXECUTE("where",print_where(conds,"after equal_items");); + /* change field = field to field = const for each found field = const */ propagate_cond_constants(thd, (I_List<COND_CMP> *) 0, conds, conds); /* |