diff options
Diffstat (limited to 'sql')
| -rw-r--r-- | sql/item.cc | 14 | ||||
| -rw-r--r-- | sql/item.h | 7 | ||||
| -rw-r--r-- | sql/item_cmpfunc.cc | 105 | ||||
| -rw-r--r-- | sql/item_cmpfunc.h | 3 | ||||
| -rw-r--r-- | sql/sql_lex.cc | 14 |
5 files changed, 89 insertions, 54 deletions
diff --git a/sql/item.cc b/sql/item.cc index 897d6cdbd69..9b721266e9d 100644 --- a/sql/item.cc +++ b/sql/item.cc @@ -7353,7 +7353,7 @@ Item *Item::build_pushable_cond(THD *thd, List<Item> equalities; Item *new_cond= NULL; if (((Item_equal *)this)->create_pushable_equalities(thd, &equalities, - checker, arg) || + checker, arg, true) || (equalities.elements == 0)) return 0; @@ -10555,3 +10555,15 @@ void Item::register_in(THD *thd) next= thd->free_list; thd->free_list= this; } + + +bool Item::cleanup_excluding_immutables_processor (void *arg) +{ + if (!(get_extraction_flag() == IMMUTABLE_FL)) + return cleanup_processor(arg); + else + { + clear_extraction_flag(); + return false; + } +} diff --git a/sql/item.h b/sql/item.h index 42ad6ba35fe..990ca0ec887 100644 --- a/sql/item.h +++ b/sql/item.h @@ -152,8 +152,10 @@ bool mark_unsupported_function(const char *w1, const char *w2, #define NO_EXTRACTION_FL (1 << 6) #define FULL_EXTRACTION_FL (1 << 7) #define DELETION_FL (1 << 8) -#define SUBSTITUTION_FL (1 << 9) -#define EXTRACTION_MASK (NO_EXTRACTION_FL | FULL_EXTRACTION_FL | DELETION_FL) +#define IMMUTABLE_FL (1 << 9) +#define SUBSTITUTION_FL (1 << 10) +#define EXTRACTION_MASK \ + (NO_EXTRACTION_FL | FULL_EXTRACTION_FL | DELETION_FL | IMMUTABLE_FL) extern const char *item_empty_name; @@ -1867,6 +1869,7 @@ public: virtual bool cleanup_processor(void *arg); virtual bool cleanup_excluding_fields_processor (void *arg) { return cleanup_processor(arg); } + bool cleanup_excluding_immutables_processor (void *arg); virtual bool cleanup_excluding_const_fields_processor (void *arg) { return cleanup_processor(arg); } virtual bool collect_item_field_processor(void *arg) { return 0; } diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc index 7a1d721ca48..b23aca2c5f3 100644 --- a/sql/item_cmpfunc.cc +++ b/sql/item_cmpfunc.cc @@ -7410,6 +7410,7 @@ Item_equal::excl_dep_on_grouping_fields(st_select_lex *sel) of the tree of the object to check if multiple equality elements can be used to create equalities @param arg parameter to be passed to the checker + @param clone_const true <=> clone the constant member if there is any @details How the method works on examples: @@ -7420,36 +7421,31 @@ Item_equal::excl_dep_on_grouping_fields(st_select_lex *sel) Example 2: It takes MULT_EQ(1,a,b) and tries to create from its elements a set of - equalities {(1=a),(1=b)}. + equalities {(a=1),(a=b)}. How it is done: - 1. The method finds the left part of the equalities to be built. It will - be the same for all equalities. It is either: - a. A constant if there is any - b. A first element in the multiple equality that satisfies - checker function + 1. If there is a constant member c the first non-constant member x for + which the function checker returns true is taken and an item for + the equality x=c is created. When constructing the equality item + the left part of the equality is always taken as a clone of x while + the right part is taken as a clone of c only if clone_const == true. - For the example 1 the left element is field 'x'. - For the example 2 it is constant '1'. + 2. After this all equalities of the form x=a (where x designates the first + non-constant member for which checker returns true and a is some other + such member of the multiplle equality) are created. When constructing + an equality item both its parts are taken as clones of x and a. - 2. If the left element is found the rest elements of the multiple equality - are checked with the checker function if they can be right parts - of equalities. - If the element can be a right part of the equality, equality is built. - It is built with the left part element found at the step 1 and - the right part element found at this step (step 2). - - Suppose for the example above that both 'a' and 'b' fields can be used - to build equalities: + Suppose in the examples above that for 'x', 'a', and 'b' the function + checker returns true. Example 1: - for 'a' field (x=a) is built - for 'b' field (x=b) is built + the equality (x=a) is built + the equality (x=b) is built Example 2: - for 'a' field (1=a) is built - for 'b' field (1=b) is built + the equality (a=1) is built + the equality (a=b) is built 3. As a result we get a set of equalities built with the elements of this multiple equality. They are saved in the equality list. @@ -7458,15 +7454,17 @@ Item_equal::excl_dep_on_grouping_fields(st_select_lex *sel) {(x=a),(x=b)} Example 2: - {(1=a),(1=b)} + {(a=1),(a=b)} @note This method is called for condition pushdown into materialized derived table/view, and IN subquery, and pushdown from HAVING into WHERE. When it is called for pushdown from HAVING the empty checker is passed. - It happens because elements of this multiple equality don't need to be - checked if they can be used to build equalities. There are no elements - that can't be used to build equalities. + This is because in this case the elements of the multiple equality don't + need to be checked if they can be used to build equalities: either all + equalities can be pushed or none of them can be pushed. + When the function is called for pushdown from HAVING the value of the + parameter clone_const is always false. In other cases it's always true. @retval true if an error occurs @retval false otherwise @@ -7475,24 +7473,42 @@ Item_equal::excl_dep_on_grouping_fields(st_select_lex *sel) bool Item_equal::create_pushable_equalities(THD *thd, List<Item> *equalities, Pushdown_checker checker, - uchar *arg) + uchar *arg, + bool clone_const) { Item *item; + Item *left_item= NULL; + Item *right_item = get_const(); Item_equal_fields_iterator it(*this); - Item *left_item = get_const(); - if (!left_item) + + while ((item=it++)) { - while ((item=it++)) - { - left_item= item; - if (checker && !((item->*checker) (arg))) - continue; - break; - } + left_item= item; + if (checker && !((item->*checker) (arg))) + continue; + break; } + if (!left_item) return false; + if (right_item) + { + Item_func_eq *eq= 0; + Item *left_item_clone= left_item->build_clone(thd); + Item *right_item_clone= !clone_const ? + right_item : right_item->build_clone(thd); + if (!left_item_clone || !right_item_clone) + return true; + eq= new (thd->mem_root) Item_func_eq(thd, + left_item_clone, + right_item_clone); + if (!eq || equalities->push_back(eq, thd->mem_root)) + return true; + if (!clone_const) + right_item->set_extraction_flag(IMMUTABLE_FL); + } + while ((item=it++)) { if (checker && !((item->*checker) (arg))) @@ -7500,15 +7516,14 @@ bool Item_equal::create_pushable_equalities(THD *thd, 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 && equalities->push_back(eq, thd->mem_root)) + if (!(left_item_clone && right_item_clone)) + return true; + 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 || equalities->push_back(eq, thd->mem_root)) return true; } return false; @@ -7533,7 +7548,7 @@ bool Item_equal::create_pushable_equalities(THD *thd, Item *Item_equal::multiple_equality_transformer(THD *thd, uchar *arg) { List<Item> equalities; - if (create_pushable_equalities(thd, &equalities, 0, 0)) + if (create_pushable_equalities(thd, &equalities, 0, 0, false)) return 0; switch (equalities.elements) diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h index 8eaa0ab7c36..178ed8360dd 100644 --- a/sql/item_cmpfunc.h +++ b/sql/item_cmpfunc.h @@ -3209,7 +3209,8 @@ public: bool excl_dep_on_in_subq_left_part(Item_in_subselect *subq_pred); bool excl_dep_on_grouping_fields(st_select_lex *sel); bool create_pushable_equalities(THD *thd, List<Item> *equalities, - Pushdown_checker checker, uchar *arg); + Pushdown_checker checker, uchar *arg, + bool clone_const); /* Return the number of elements in this multiple equality */ uint elements_count() { return equal_items.elements; } friend class Item_equal_fields_iterator; diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc index ff40a46d7fd..6539b1e471f 100644 --- a/sql/sql_lex.cc +++ b/sql/sql_lex.cc @@ -7988,7 +7988,7 @@ st_select_lex::check_cond_extraction_for_grouping_fields(THD *thd, Item *cond) } else { - int fl= cond->excl_dep_on_grouping_fields(this) ? + int fl= cond->excl_dep_on_grouping_fields(this) && !cond->is_expensive() ? FULL_EXTRACTION_FL : NO_EXTRACTION_FL; cond->set_extraction_flag(fl); } @@ -9819,7 +9819,7 @@ st_select_lex::build_pushable_cond_for_having_pushdown(THD *thd, Item *cond) { List_iterator<Item> li(*((Item_cond*) result)->argument_list()); Item *item; - while ((item=li++)) + while ((item= li++)) { if (attach_to_conds.push_back(item, thd->mem_root)) return true; @@ -9839,8 +9839,13 @@ st_select_lex::build_pushable_cond_for_having_pushdown(THD *thd, Item *cond) */ if (cond->type() != Item::COND_ITEM) return false; + if (((Item_cond *)cond)->functype() != Item_cond::COND_AND_FUNC) { + /* + cond is not a conjunctive formula and it cannot be pushed into WHERE. + Try to extract a formula that can be pushed. + */ Item *fix= cond->build_pushable_cond(thd, 0, 0); if (!fix) return false; @@ -9860,7 +9865,6 @@ st_select_lex::build_pushable_cond_for_having_pushdown(THD *thd, Item *cond) Item *result= item->transform(thd, &Item::multiple_equality_transformer, (uchar *)item); - if (!result) return true; if (result->type() == Item::COND_ITEM && @@ -10188,8 +10192,8 @@ Item *st_select_lex::pushdown_from_having_into_where(THD *thd, Item *having) &Item::field_transformer_for_having_pushdown, (uchar *)this); - if (item->walk(&Item:: cleanup_processor, 0, STOP_PTR) || - item->fix_fields(thd, NULL)) + if (item->walk(&Item::cleanup_excluding_immutables_processor, 0, STOP_PTR) + || item->fix_fields(thd, NULL)) { attach_to_conds.empty(); goto exit; |