diff options
Diffstat (limited to 'sql/item_subselect.h')
| -rw-r--r-- | sql/item_subselect.h | 96 |
1 files changed, 67 insertions, 29 deletions
diff --git a/sql/item_subselect.h b/sql/item_subselect.h index 1da129380e7..e806f45041a 100644 --- a/sql/item_subselect.h +++ b/sql/item_subselect.h @@ -244,6 +244,7 @@ public: virtual bool expr_cache_is_needed(THD *); virtual void get_cache_parameters(List<Item> ¶meters); virtual bool is_subquery_processor (uchar *opt_arg) { return 1; } + bool exists2in_processor(uchar *opt_arg) { return 0; } bool limit_index_condition_pushdown_processor(uchar *opt_arg) { return TRUE; @@ -286,6 +287,7 @@ public: bool val_bool(); bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate); enum Item_result result_type() const; + enum Item_result cmp_type() const; enum_field_types field_type() const; void fix_length_and_dec(); @@ -338,13 +340,35 @@ public: class Item_exists_subselect :public Item_subselect { protected: + Item_func_not *upper_not; bool value; /* value of this item (boolean: exists/not-exists) */ + bool abort_on_null; void init_length_and_dec(); + bool select_prepare_to_be_in(); public: + /* + Used by subquery optimizations to keep track about in which clause this + subquery predicate is located: + NO_JOIN_NEST - the predicate is an AND-part of the WHERE + join nest pointer - the predicate is an AND-part of ON expression + of a join nest + NULL - for all other locations + */ + TABLE_LIST *emb_on_expr_nest; + /** + Reference on the Item_in_optimizer wrapper of this subquery + */ + Item_in_optimizer *optimizer; + /* true if we got this from EXISTS or to IN */ + bool exists_transformed; + Item_exists_subselect(st_select_lex *select_lex); - Item_exists_subselect(): Item_subselect() {} + Item_exists_subselect() + :Item_subselect(), upper_not(NULL),abort_on_null(0), + emb_on_expr_nest(NULL), optimizer(0), exists_transformed(0) + {} subs_type substype() { return EXISTS_SUBS; } void reset() @@ -360,11 +384,24 @@ public: String *val_str(String*); my_decimal *val_decimal(my_decimal *); bool val_bool(); + bool fix_fields(THD *thd, Item **ref); void fix_length_and_dec(); virtual void print(String *str, enum_query_type query_type); + bool select_transformer(JOIN *join); + void top_level_item() { abort_on_null=1; } + inline bool is_top_level_item() { return abort_on_null; } + bool exists2in_processor(uchar *opt_arg); Item* expr_cache_insert_transformer(uchar *thd_arg); + void mark_as_condition_AND_part(TABLE_LIST *embedding) + { + emb_on_expr_nest= embedding; + } + virtual void under_not(Item_func_not *upper) { upper_not= upper; }; + + void set_exists_transformed() { exists_transformed= TRUE; } + friend class select_exists_subselect; friend class subselect_uniquesubquery_engine; friend class subselect_indexsubquery_engine; @@ -424,11 +461,8 @@ protected: */ Item *expr; bool was_null; - bool abort_on_null; /* A bitmap of possible execution strategies for an IN predicate. */ uchar in_strategy; -public: - Item_in_optimizer *optimizer; protected: /* Used to trigger on/off conditions that were pushed down to subselect */ bool *pushed_cond_guards; @@ -451,15 +485,6 @@ public: /* Priority of this predicate in the convert-to-semi-join-nest process. */ int sj_convert_priority; /* - Used by subquery optimizations to keep track about in which clause this - subquery predicate is located: - NO_JOIN_NEST - the predicate is an AND-part of the WHERE - join nest pointer - the predicate is an AND-part of ON expression - of a join nest - NULL - for all other locations - */ - TABLE_LIST *emb_on_expr_nest; - /* Types of left_expr and subquery's select list allow to perform subquery materialization. Currently, we set this to FALSE when it as well could be TRUE. This is to be properly addressed with fix for BUG#36752. @@ -527,7 +552,9 @@ public: */ Item *original_item() { - return is_flattenable_semijoin ? (Item*)this : (Item*)optimizer; + return (is_flattenable_semijoin && !exists_transformed ? + (Item*)this : + (Item*)optimizer); } bool *get_cond_guard(int i) @@ -546,11 +573,9 @@ public: Item_in_subselect(Item * left_expr, st_select_lex *select_lex); Item_in_subselect() :Item_exists_subselect(), left_expr_cache(0), first_execution(TRUE), - abort_on_null(0), in_strategy(SUBS_NOT_TRANSFORMED), optimizer(0), - pushed_cond_guards(NULL), func(NULL), emb_on_expr_nest(NULL), - is_jtbm_merged(FALSE), is_jtbm_const_tab(FALSE), - upper_item(0) - {} + in_strategy(SUBS_NOT_TRANSFORMED), + pushed_cond_guards(NULL), func(NULL), is_jtbm_merged(FALSE), + is_jtbm_const_tab(FALSE), upper_item(0) {} void cleanup(); subs_type substype() { return IN_SUBS; } void reset() @@ -571,8 +596,6 @@ public: my_decimal *val_decimal(my_decimal *); void update_null_value () { (void) val_bool(); } bool val_bool(); - void top_level_item() { abort_on_null=1; } - inline bool is_top_level_item() { return abort_on_null; } bool test_limit(st_select_lex_unit *unit); virtual void print(String *str, enum_query_type query_type); bool fix_fields(THD *thd, Item **ref); @@ -589,19 +612,14 @@ public: void set_first_execution() { if (first_execution) first_execution= FALSE; } bool expr_cache_is_needed(THD *thd); inline bool left_expr_has_null(); - + int optimize(double *out_rows, double *cost); - /* + /* Return the identifier that we could use to identify the subquery for the user. */ int get_identifier(); - void mark_as_condition_AND_part(TABLE_LIST *embedding) - { - emb_on_expr_nest= embedding; - } - bool test_strategy(uchar strategy) { return test(in_strategy & strategy); } @@ -630,6 +648,9 @@ public: void add_strategy (uchar strategy) { + DBUG_ENTER("Item_in_subselect::add_strategy"); + DBUG_PRINT("enter", ("current: %u add: %u", + (uint) in_strategy, (uint) strategy)); DBUG_ASSERT(strategy != SUBS_NOT_TRANSFORMED); DBUG_ASSERT(!(strategy & SUBS_STRATEGY_CHOSEN)); /* @@ -639,16 +660,25 @@ public: DBUG_ASSERT(!(in_strategy & SUBS_STRATEGY_CHOSEN)); */ in_strategy|= strategy; + DBUG_VOID_RETURN; } void reset_strategy(uchar strategy) { + DBUG_ENTER("Item_in_subselect::reset_strategy"); + DBUG_PRINT("enter", ("current: %u new: %u", + (uint) in_strategy, (uint) strategy)); DBUG_ASSERT(strategy != SUBS_NOT_TRANSFORMED); in_strategy= strategy; + DBUG_VOID_RETURN; } void set_strategy(uchar strategy) { + DBUG_ENTER("Item_in_subselect::set_strategy"); + DBUG_PRINT("enter", ("current: %u set: %u", + (uint) in_strategy, + (uint) (SUBS_STRATEGY_CHOSEN | strategy))); /* Check that only one strategy is set for execution. */ DBUG_ASSERT(strategy == SUBS_SEMI_JOIN || strategy == SUBS_IN_TO_EXISTS || @@ -658,7 +688,12 @@ public: strategy == SUBS_MAXMIN_INJECTED || strategy == SUBS_MAXMIN_ENGINE); in_strategy= (SUBS_STRATEGY_CHOSEN | strategy); + DBUG_VOID_RETURN; } + bool exists2in_processor(uchar *opt_arg __attribute__((unused))) + { + return 0; + }; friend class Item_ref_null_helper; friend class Item_is_not_null_test; @@ -666,6 +701,7 @@ public: friend class subselect_indexsubquery_engine; friend class subselect_hash_sj_engine; friend class subselect_partial_match_engine; + friend class Item_exists_subselect; }; @@ -698,6 +734,7 @@ protected: THD *thd; /* pointer to current THD */ Item_subselect *item; /* item, that use this engine */ enum Item_result res_type; /* type of results */ + enum Item_result cmp_type; /* how to compare the results */ enum_field_types res_field_type; /* column type of the results */ bool maybe_null; /* may be null (first item in select) */ public: @@ -712,7 +749,7 @@ public: { result= res; item= si; - res_type= STRING_RESULT; + cmp_type= res_type= STRING_RESULT; res_field_type= MYSQL_TYPE_VAR_STRING; maybe_null= 0; set_thd(thd_arg); @@ -752,6 +789,7 @@ public: virtual uint cols()= 0; /* return number of columns in select */ virtual uint8 uncacheable()= 0; /* query is uncacheable */ enum Item_result type() { return res_type; } + enum Item_result cmptype() { return cmp_type; } enum_field_types field_type() { return res_field_type; } virtual void exclude()= 0; virtual bool may_be_null() { return maybe_null; }; |