diff options
Diffstat (limited to 'sql/table.cc')
| -rw-r--r-- | sql/table.cc | 194 |
1 files changed, 0 insertions, 194 deletions
diff --git a/sql/table.cc b/sql/table.cc index 577ed20a87e..cb3eb068e68 100644 --- a/sql/table.cc +++ b/sql/table.cc @@ -8315,200 +8315,6 @@ double KEY::actual_rec_per_key(uint i) } -/** - @brief - Mark subformulas of a condition unusable for the condition pushed into table - - @param cond The condition whose subformulas are to be marked - - @details - This method recursively traverses the AND-OR condition cond and for each subformula - of the codition it checks whether it can be usable for the extraction of a condition - that can be pushed into this table. The subformulas that are not usable are - marked with the flag NO_EXTRACTION_FL. - @note - This method is called before any call of TABLE_LIST::build_pushable_cond_for_table. - The flag NO_EXTRACTION_FL set in a subformula allows to avoid building clone - for the subformula when extracting the pushable condition. -*/ - -void TABLE_LIST::check_pushable_cond_for_table(Item *cond) -{ - table_map tab_map= table->map; - cond->clear_extraction_flag(); - if (cond->type() == Item::COND_ITEM) - { - bool and_cond= ((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC; - List_iterator<Item> li(*((Item_cond*) cond)->argument_list()); - uint count= 0; - Item *item; - while ((item=li++)) - { - check_pushable_cond_for_table(item); - if (item->get_extraction_flag() != NO_EXTRACTION_FL) - count++; - else if (!and_cond) - break; - } - if ((and_cond && count == 0) || item) - { - cond->set_extraction_flag(NO_EXTRACTION_FL); - if (and_cond) - li.rewind(); - while ((item= li++)) - item->clear_extraction_flag(); - } - } - else if (!cond->excl_dep_on_table(tab_map)) - cond->set_extraction_flag(NO_EXTRACTION_FL); -} - - -/** - @brief - Build condition extractable from the given one depended only on this table - - @param thd The thread handle - @param cond The condition from which the pushable one is to be extracted - - @details - For the given condition cond this method finds out what condition depended - only on this table can be extracted from cond. If such condition C exists - the method builds the item for it. - The method uses the flag NO_EXTRACTION_FL set by the preliminary call of - the method TABLE_LIST::check_pushable_cond_for_table to figure out whether - a subformula depends only on this table or not. - @note - The built condition C is always implied by the condition cond - (cond => C). The method tries to build the most restictive such - condition (i.e. for any other condition C' such that cond => C' - we have C => C'). - @note - The build item is not ready for usage: substitution for the field items - has to be done and it has to be re-fixed. - - @retval - the built condition pushable into this table if such a condition exists - NULL if there is no such a condition -*/ - -Item* TABLE_LIST::build_pushable_cond_for_table(THD *thd, Item *cond) -{ - table_map tab_map= table->map; - bool is_multiple_equality= cond->type() == Item::FUNC_ITEM && - ((Item_func*) cond)->functype() == Item_func::MULT_EQUAL_FUNC; - if (cond->get_extraction_flag() == NO_EXTRACTION_FL) - return 0; - if (cond->type() == Item::COND_ITEM) - { - bool cond_and= false; - Item_cond *new_cond; - if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC) - { - cond_and= true; - new_cond=new (thd->mem_root) Item_cond_and(thd); - } - else - new_cond= new (thd->mem_root) Item_cond_or(thd); - if (!new_cond) - return 0; - List_iterator<Item> li(*((Item_cond*) cond)->argument_list()); - Item *item; - bool is_fix_needed= false; - while ((item=li++)) - { - if (item->get_extraction_flag() == NO_EXTRACTION_FL) - { - if (!cond_and) - return 0; - continue; - } - Item *fix= build_pushable_cond_for_table(thd, item); - if (!fix && !cond_and) - return 0; - if (!fix) - continue; - - if (fix->type() == Item::COND_ITEM && - ((Item_cond*) fix)->functype() == Item_func::COND_AND_FUNC) - is_fix_needed= true; - - new_cond->argument_list()->push_back(fix, thd->mem_root); - } - if (is_fix_needed) - new_cond->fix_fields(thd, 0); - - switch (new_cond->argument_list()->elements) - { - case 0: - return 0; - case 1: - return new_cond->argument_list()->head(); - default: - return new_cond; - } - } - else if (is_multiple_equality) - { - if (!(cond->used_tables() & tab_map)) - return 0; - Item *new_cond= NULL; - int i= 0; - Item_equal *item_equal= (Item_equal *) cond; - Item *left_item = item_equal->get_const(); - Item_equal_fields_iterator it(*item_equal); - Item *item; - if (!left_item) - { - while ((item=it++)) - if (item->used_tables() == tab_map) - { - left_item= item; - break; - } - } - if (!left_item) - return 0; - while ((item=it++)) - { - if (!(item->used_tables() == tab_map)) - continue; - Item_func_eq *eq= 0; - Item *left_item_clone= left_item->build_clone(thd); - Item *right_item_clone= item->build_clone(thd); - if (left_item_clone && right_item_clone) - { - left_item_clone->set_item_equal(NULL); - right_item_clone->set_item_equal(NULL); - eq= new (thd->mem_root) Item_func_eq(thd, right_item_clone, - left_item_clone); - } - if (eq) - { - i++; - switch (i) - { - case 1: - new_cond= eq; - break; - case 2: - new_cond= new (thd->mem_root) Item_cond_and(thd, new_cond, eq); - break; - default: - ((Item_cond_and*)new_cond)->argument_list()->push_back(eq, - thd->mem_root); - } - } - } - if (new_cond) - new_cond->fix_fields(thd, &new_cond); - return new_cond; - } - else if (cond->get_extraction_flag() != NO_EXTRACTION_FL) - return cond->build_clone(thd); - return 0; -} - LEX_CSTRING *fk_option_name(enum_fk_option opt) { static LEX_CSTRING names[]= |