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Diffstat (limited to 'sql/sql_select.h')
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diff --git a/sql/sql_select.h b/sql/sql_select.h new file mode 100644 index 00000000..4f2719f1 --- /dev/null +++ b/sql/sql_select.h @@ -0,0 +1,2595 @@ +#ifndef SQL_SELECT_INCLUDED +#define SQL_SELECT_INCLUDED + +/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. + Copyright (c) 2008, 2022, MariaDB Corporation. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */ + +/** + @file + + @brief + classes to use when handling where clause +*/ + +#ifdef USE_PRAGMA_INTERFACE +#pragma interface /* gcc class implementation */ +#endif + +#include "procedure.h" +#include "sql_array.h" /* Array */ +#include "records.h" /* READ_RECORD */ +#include "opt_range.h" /* SQL_SELECT, QUICK_SELECT_I */ +#include "filesort.h" + +#include "cset_narrowing.h" + +typedef struct st_join_table JOIN_TAB; +/* Values in optimize */ +#define KEY_OPTIMIZE_EXISTS 1U +#define KEY_OPTIMIZE_REF_OR_NULL 2U +#define KEY_OPTIMIZE_EQ 4U + +inline uint get_hash_join_key_no() { return MAX_KEY; } + +inline bool is_hash_join_key_no(uint key) { return key == MAX_KEY; } + +typedef struct keyuse_t { + TABLE *table; + Item *val; /**< or value if no field */ + table_map used_tables; + uint key, keypart, optimize; + key_part_map keypart_map; + ha_rows ref_table_rows; + /** + If true, the comparison this value was created from will not be + satisfied if val has NULL 'value'. + */ + bool null_rejecting; + /* + !NULL - This KEYUSE was created from an equality that was wrapped into + an Item_func_trig_cond. This means the equality (and validity of + this KEYUSE element) can be turned on and off. The on/off state + is indicted by the pointed value: + *cond_guard == TRUE <=> equality condition is on + *cond_guard == FALSE <=> equality condition is off + + NULL - Otherwise (the source equality can't be turned off) + */ + bool *cond_guard; + /* + 0..64 <=> This was created from semi-join IN-equality # sj_pred_no. + MAX_UINT Otherwise + */ + uint sj_pred_no; + + /* + If this is NULL than KEYUSE is always enabled. + Otherwise it points to the enabling flag for this keyuse (true <=> enabled) + */ + bool *validity_ref; + + bool is_for_hash_join() { return is_hash_join_key_no(key); } +} KEYUSE; + + +struct KEYUSE_EXT: public KEYUSE +{ + /* + This keyuse can be used only when the partial join being extended + contains the tables from this table map + */ + table_map needed_in_prefix; + /* The enabling flag for keyuses usable for splitting */ + bool validity_var; +}; + +/// Used when finding key fields +struct KEY_FIELD { + Field *field; + Item_bool_func *cond; + Item *val; ///< May be empty if diff constant + uint level; + uint optimize; + bool eq_func; + /** + If true, the condition this struct represents will not be satisfied + when val IS NULL. + */ + bool null_rejecting; + bool *cond_guard; /* See KEYUSE::cond_guard */ + uint sj_pred_no; /* See KEYUSE::sj_pred_no */ +}; + + +#define NO_KEYPART ((uint)(-1)) + +class store_key; + +const int NO_REF_PART= uint(-1); + +typedef struct st_table_ref +{ + bool key_err; + /** True if something was read into buffer in join_read_key. */ + bool has_record; + uint key_parts; ///< num of ... + uint key_length; ///< length of key_buff + int key; ///< key no + uchar *key_buff; ///< value to look for with key + uchar *key_buff2; ///< key_buff+key_length + store_key **key_copy; // + + /* + Bitmap of key parts which refer to constants. key_copy only has copiers for + non-const key parts. + */ + key_part_map const_ref_part_map; + + Item **items; ///< val()'s for each keypart + /* + Array of pointers to trigger variables. Some/all of the pointers may be + NULL. The ref access can be used iff + + for each used key part i, (!cond_guards[i] || *cond_guards[i]) + + This array is used by subquery code. The subquery code may inject + triggered conditions, i.e. conditions that can be 'switched off'. A ref + access created from such condition is not valid when at least one of the + underlying conditions is switched off (see subquery code for more details) + */ + bool **cond_guards; + /** + (null_rejecting & (1<<i)) means the condition is '=' and no matching + rows will be produced if items[i] IS NULL (see add_not_null_conds()) + */ + key_part_map null_rejecting; + table_map depend_map; ///< Table depends on these tables. + + /* null byte position in the key_buf. Used for REF_OR_NULL optimization */ + uchar *null_ref_key; + /* + ref_or_null optimization: number of key part that alternates between + the lookup value or NULL (there's only one such part). + If we're not using ref_or_null, the value is NO_REF_PART + */ + uint null_ref_part; + + /* + The number of times the record associated with this key was used + in the join. + */ + ha_rows use_count; + + /* + TRUE <=> disable the "cache" as doing lookup with the same key value may + produce different results (because of Index Condition Pushdown) + + */ + bool disable_cache; + + /* + If true, this ref access was constructed from equalities generated by + LATERAL DERIVED (aka GROUP BY splitting) optimization + */ + bool uses_splitting; + + bool tmp_table_index_lookup_init(THD *thd, KEY *tmp_key, Item_iterator &it, + bool value, uint skip= 0); + bool is_access_triggered(); +} TABLE_REF; + + +/* + The structs which holds the join connections and join states +*/ +enum join_type { JT_UNKNOWN,JT_SYSTEM,JT_CONST,JT_EQ_REF,JT_REF,JT_MAYBE_REF, + JT_ALL, JT_RANGE, JT_NEXT, JT_FT, JT_REF_OR_NULL, + JT_UNIQUE_SUBQUERY, JT_INDEX_SUBQUERY, JT_INDEX_MERGE, + JT_HASH, JT_HASH_RANGE, JT_HASH_NEXT, JT_HASH_INDEX_MERGE}; + +class JOIN; + +enum enum_nested_loop_state +{ + NESTED_LOOP_KILLED= -2, NESTED_LOOP_ERROR= -1, + NESTED_LOOP_OK= 0, NESTED_LOOP_NO_MORE_ROWS= 1, + NESTED_LOOP_QUERY_LIMIT= 3, NESTED_LOOP_CURSOR_LIMIT= 4 +}; + + +/* Possible sj_strategy values */ +enum sj_strategy_enum +{ + SJ_OPT_NONE=0, + SJ_OPT_DUPS_WEEDOUT=1, + SJ_OPT_LOOSE_SCAN =2, + SJ_OPT_FIRST_MATCH =3, + SJ_OPT_MATERIALIZE =4, + SJ_OPT_MATERIALIZE_SCAN=5 +}; + +/* Values for JOIN_TAB::packed_info */ +#define TAB_INFO_HAVE_VALUE 1U +#define TAB_INFO_USING_INDEX 2U +#define TAB_INFO_USING_WHERE 4U +#define TAB_INFO_FULL_SCAN_ON_NULL 8U + +typedef enum_nested_loop_state +(*Next_select_func)(JOIN *, struct st_join_table *, bool); +Next_select_func setup_end_select_func(JOIN *join); +int rr_sequential(READ_RECORD *info); +int read_record_func_for_rr_and_unpack(READ_RECORD *info); +Item *remove_pushed_top_conjuncts(THD *thd, Item *cond); +Item *and_new_conditions_to_optimized_cond(THD *thd, Item *cond, + COND_EQUAL **cond_eq, + List<Item> &new_conds, + Item::cond_result *cond_value); + +#include "sql_explain.h" + +/************************************************************************************** + * New EXPLAIN structures END + *************************************************************************************/ + +class JOIN_CACHE; +class SJ_TMP_TABLE; +class JOIN_TAB_RANGE; +class AGGR_OP; +class Filesort; +struct SplM_plan_info; +class SplM_opt_info; + +typedef struct st_join_table { + TABLE *table; + TABLE_LIST *tab_list; + KEYUSE *keyuse; /**< pointer to first used key */ + KEY *hj_key; /**< descriptor of the used best hash join key + not supported by any index */ + SQL_SELECT *select; + 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 + Pushdown. We may need to restore everything back if we first choose one + index but then reconsider (see test_if_skip_sort_order() for such + scenarios). + NULL means no index condition pushdown was performed. + */ + Item *pre_idx_push_select_cond; + /* + Pointer to the associated ON expression. on_expr_ref=!NULL except for + degenerate joins. + + Optimization phase: *on_expr_ref!=NULL for tables that are the single + tables on the inner side of the outer join (t1 LEFT JOIN t2 ON...) + + Execution phase: *on_expr_ref!=NULL for tables that are first inner tables + within an outer join (which may have multiple tables) + */ + Item **on_expr_ref; + COND_EQUAL *cond_equal; /**< multiple equalities for the on expression */ + st_join_table *first_inner; /**< first inner table for including outerjoin */ + bool found; /**< true after all matches or null complement */ + bool not_null_compl;/**< true before null complement is added */ + st_join_table *last_inner; /**< last table table for embedding outer join */ + st_join_table *first_upper; /**< first inner table for embedding outer join */ + st_join_table *first_unmatched; /**< used for optimization purposes only */ + + /* + For join tabs that are inside an SJM bush: root of the bush + */ + st_join_table *bush_root_tab; + + /* TRUE <=> This join_tab is inside an SJM bush and is the last leaf tab here */ + bool last_leaf_in_bush; + + /* + ptr - this is a bush, and ptr points to description of child join_tab + range + NULL - this join tab has no bush children + */ + JOIN_TAB_RANGE *bush_children; + + /* Special content for EXPLAIN 'Extra' column or NULL if none */ + enum explain_extra_tag info; + + Table_access_tracker *tracker; + + Table_access_tracker *jbuf_tracker; + Time_and_counter_tracker *jbuf_unpack_tracker; + Counter_tracker *jbuf_loops_tracker; + /* + Bitmap of TAB_INFO_* bits that encodes special line for EXPLAIN 'Extra' + column, or 0 if there is no info. + */ + uint packed_info; + + // READ_RECORD::Setup_func materialize_table; + READ_RECORD::Setup_func read_first_record; + Next_select_func next_select; + READ_RECORD read_record; + /* + Currently the following two fields are used only for a [NOT] IN subquery + if it is executed by an alternative full table scan when the left operand of + the subquery predicate is evaluated to NULL. + */ + READ_RECORD::Setup_func save_read_first_record;/* to save read_first_record */ + READ_RECORD::Read_func save_read_record;/* to save read_record.read_record */ + double worst_seeks; + key_map const_keys; /**< Keys with constant part */ + key_map checked_keys; /**< Keys checked in find_best */ + key_map needed_reg; + key_map keys; /**< all keys with can be used */ + + /* Either #rows in the table or 1 for const table. */ + ha_rows records; + /* + Number of records that will be scanned (yes scanned, not returned) by the + best 'independent' access method, i.e. table scan or QUICK_*_SELECT) + */ + ha_rows found_records; + /* + Cost of accessing the table using "ALL" or range/index_merge access + method (but not 'index' for some reason), i.e. this matches method which + E(#records) is in found_records. + */ + double read_time; + + /* Copy of POSITION::records_read, set by get_best_combination() */ + double records_read; + + /* The selectivity of the conditions that can be pushed to the table */ + double cond_selectivity; + + /* Startup cost for execution */ + double startup_cost; + + double partial_join_cardinality; + + table_map dependent,key_dependent; + /* + This is set for embedded sub queries. It contains the table map of + the outer expression, like 'A' in the following expression: + WHERE A in (SELECT ....) + */ + table_map embedded_dependent; + + /* + 1 - use quick select + 2 - use "Range checked for each record" + */ + uint use_quick; + /* + Index to use. Note: this is valid only for 'index' access, but not range or + ref access. + */ + uint index; + uint status; ///< Save status for cache + uint used_fields; + ulong used_fieldlength; + ulong max_used_fieldlength; + uint used_blobs; + uint used_null_fields; + uint used_uneven_bit_fields; + enum join_type type; + /* If first key part is used for any key in 'key_dependent' */ + bool key_start_dependent; + bool cached_eq_ref_table,eq_ref_table; + bool shortcut_for_distinct; + bool sorted; + /* + If it's not 0 the number stored this field indicates that the index + scan has been chosen to access the table data and we expect to scan + this number of rows for the table. + */ + ha_rows limit; + TABLE_REF ref; + /* TRUE <=> condition pushdown supports other tables presence */ + bool icp_other_tables_ok; + /* + TRUE <=> condition pushed to the index has to be factored out of + the condition pushed to the table + */ + bool idx_cond_fact_out; + bool use_join_cache; + /* TRUE <=> it is prohibited to join this table using join buffer */ + bool no_forced_join_cache; + uint used_join_cache_level; + JOIN_CACHE *cache; + /* + Index condition for BKA access join + */ + Item *cache_idx_cond; + SQL_SELECT *cache_select; + AGGR_OP *aggr; + JOIN *join; + /* + Embedding SJ-nest (may be not the direct parent), or NULL if none. + This variable holds the result of table pullout. + */ + TABLE_LIST *emb_sj_nest; + + /* FirstMatch variables (final QEP) */ + struct st_join_table *first_sj_inner_tab; + struct st_join_table *last_sj_inner_tab; + + /* Variables for semi-join duplicate elimination */ + SJ_TMP_TABLE *flush_weedout_table; + SJ_TMP_TABLE *check_weed_out_table; + /* for EXPLAIN only: */ + SJ_TMP_TABLE *first_weedout_table; + + /** + reference to saved plan and execution statistics + */ + Explain_table_access *explain_plan; + + /* + If set, means we should stop join enumeration after we've got the first + match and return to the specified join tab. May point to + join->join_tab[-1] which means stop join execution after the first + match. + */ + struct st_join_table *do_firstmatch; + + /* + ptr - We're doing a LooseScan, this join tab is the first (i.e. + "driving") join tab), and ptr points to the last join tab + handled by the strategy. loosescan_match_tab->found_match + should be checked to see if the current value group had a match. + NULL - Not doing a loose scan on this join tab. + */ + struct st_join_table *loosescan_match_tab; + + /* TRUE <=> we are inside LooseScan range */ + bool inside_loosescan_range; + + /* Buffer to save index tuple to be able to skip duplicates */ + uchar *loosescan_buf; + + /* + Index used by LooseScan (we store it here separately because ref access + stores it in tab->ref.key, while range scan stores it in tab->index, etc) + */ + uint loosescan_key; + + /* Length of key tuple (depends on #keyparts used) to store in the above */ + uint loosescan_key_len; + + /* Used by LooseScan. TRUE<=> there has been a matching record combination */ + bool found_match; + + /* + Used by DuplicateElimination. tab->table->ref must have the rowid + whenever we have a current record. + */ + int keep_current_rowid; + + /* NestedOuterJoins: Bitmap of nested joins this table is part of */ + nested_join_map embedding_map; + + /* Tmp table info */ + TMP_TABLE_PARAM *tmp_table_param; + + /* Sorting related info */ + Filesort *filesort; + SORT_INFO *filesort_result; + + /* + Non-NULL value means this join_tab must do window function computation + before reading. + */ + Window_funcs_computation* window_funcs_step; + + /** + List of topmost expressions in the select list. The *next* JOIN_TAB + in the plan should use it to obtain correct values. Same applicable to + all_fields. These lists are needed because after tmp tables functions + will be turned to fields. These variables are pointing to + tmp_fields_list[123]. Valid only for tmp tables and the last non-tmp + table in the query plan. + @see JOIN::make_aggr_tables_info() + */ + List<Item> *fields; + /** List of all expressions in the select list */ + List<Item> *all_fields; + /* + Pointer to the ref array slice which to switch to before sending + records. Valid only for tmp tables. + */ + Ref_ptr_array *ref_array; + + /** Number of records saved in tmp table */ + ha_rows send_records; + + /** HAVING condition for checking prior saving a record into tmp table*/ + Item *having; + + /** TRUE <=> remove duplicates on this table. */ + bool distinct; + + /* + Semi-join strategy to be used for this join table. This is a copy of + POSITION::sj_strategy field. This field is set up by the + fix_semijoin_strategies_for_picked_join_order. + */ + enum sj_strategy_enum sj_strategy; + + uint n_sj_tables; + + bool preread_init_done; + + /* true <=> split optimization has been applied to this materialized table */ + bool is_split_derived; + + /* + Bitmap of split materialized derived tables that can be filled just before + this join table is to be joined. All parameters of the split derived tables + belong to tables preceding this join table. + */ + table_map split_derived_to_update; + + /* + Cost info to the range filter used when joining this join table + (Defined when the best join order has been already chosen) + */ + Range_rowid_filter_cost_info *range_rowid_filter_info; + /* Rowid filter to be used when joining this join table */ + Rowid_filter *rowid_filter; + /* Becomes true just after the used range filter has been built / filled */ + bool is_rowid_filter_built; + + bool build_range_rowid_filter_if_needed(); + + void cleanup(); + inline bool is_using_loose_index_scan() + { + const SQL_SELECT *sel= get_sql_select(); + return (sel && sel->quick && + (sel->quick->get_type() == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX)); + } + bool is_using_agg_loose_index_scan () + { + const SQL_SELECT *sel= get_sql_select(); + return (is_using_loose_index_scan() && + ((QUICK_GROUP_MIN_MAX_SELECT *)sel->quick)->is_agg_distinct()); + } + const SQL_SELECT *get_sql_select() + { + return filesort ? filesort->select : select; + } + bool is_inner_table_of_semi_join_with_first_match() + { + return first_sj_inner_tab != NULL; + } + bool is_inner_table_of_semijoin() + { + return emb_sj_nest != NULL; + } + bool is_inner_table_of_outer_join() + { + return first_inner != NULL; + } + bool is_single_inner_of_semi_join_with_first_match() + { + return first_sj_inner_tab == this && last_sj_inner_tab == this; + } + bool is_single_inner_of_outer_join() + { + return first_inner == this && first_inner->last_inner == this; + } + bool is_first_inner_for_outer_join() + { + return first_inner == this; + } + bool use_match_flag() + { + return is_first_inner_for_outer_join() || first_sj_inner_tab == this ; + } + bool check_only_first_match() + { + return is_inner_table_of_semi_join_with_first_match() || + (is_inner_table_of_outer_join() && + table->reginfo.not_exists_optimize); + } + bool is_last_inner_table() + { + return (first_inner && first_inner->last_inner == this) || + last_sj_inner_tab == this; + } + /* + Check whether the table belongs to a nest of inner tables of an + outer join or to a nest of inner tables of a semi-join + */ + bool is_nested_inner() + { + if (first_inner && + (first_inner != first_inner->last_inner || first_inner->first_upper)) + return TRUE; + if (first_sj_inner_tab && first_sj_inner_tab != last_sj_inner_tab) + return TRUE; + return FALSE; + } + struct st_join_table *get_first_inner_table() + { + if (first_inner) + return first_inner; + return first_sj_inner_tab; + } + void set_select_cond(COND *to, uint line) + { + DBUG_PRINT("info", ("select_cond changes %p -> %p at line %u tab %p", + select_cond, to, line, this)); + select_cond= to; + } + COND *set_cond(COND *new_cond) + { + COND *tmp_select_cond= select_cond; + set_select_cond(new_cond, __LINE__); + if (select) + select->cond= new_cond; + return tmp_select_cond; + } + void calc_used_field_length(bool max_fl); + ulong get_used_fieldlength() + { + if (!used_fieldlength) + calc_used_field_length(FALSE); + return used_fieldlength; + } + ulong get_max_used_fieldlength() + { + if (!max_used_fieldlength) + calc_used_field_length(TRUE); + return max_used_fieldlength; + } + double get_partial_join_cardinality() { return partial_join_cardinality; } + bool hash_join_is_possible(); + int make_scan_filter(); + bool is_ref_for_hash_join() { return is_hash_join_key_no(ref.key); } + KEY *get_keyinfo_by_key_no(uint key) + { + return (is_hash_join_key_no(key) ? hj_key : table->key_info+key); + } + double scan_time(); + ha_rows get_examined_rows(); + bool preread_init(); + + bool pfs_batch_update(JOIN *join); + + bool is_sjm_nest() { return MY_TEST(bush_children); } + + /* + If this join_tab reads a non-merged semi-join (also called jtbm), return + the select's number. Otherwise, return 0. + */ + int get_non_merged_semijoin_select() const + { + Item_in_subselect *subq; + if (table->pos_in_table_list && + (subq= table->pos_in_table_list->jtbm_subselect)) + { + return subq->unit->first_select()->select_number; + } + return 0; /* Not a merged semi-join */ + } + + bool access_from_tables_is_allowed(table_map used_tables, + table_map sjm_lookup_tables) + { + table_map used_sjm_lookup_tables= used_tables & sjm_lookup_tables; + return !used_sjm_lookup_tables || + (emb_sj_nest && + !(used_sjm_lookup_tables & ~emb_sj_nest->sj_inner_tables)); + } + + bool keyuse_is_valid_for_access_in_chosen_plan(JOIN *join, KEYUSE *keyuse); + + void remove_redundant_bnl_scan_conds(); + + bool save_explain_data(Explain_table_access *eta, table_map prefix_tables, + bool distinct, struct st_join_table *first_top_tab); + + bool use_order() const; ///< Use ordering provided by chosen index? + bool sort_table(); + bool remove_duplicates(); + + void partial_cleanup(); + void add_keyuses_for_splitting(); + SplM_plan_info *choose_best_splitting(uint idx, + table_map remaining_tables, + const POSITION *join_positions, + table_map *spl_pd_boundary); + bool fix_splitting(SplM_plan_info *spl_plan, table_map excluded_tables, + bool is_const_table); +} JOIN_TAB; + + +#include "sql_join_cache.h" + +enum_nested_loop_state +sub_select_cache(JOIN *join, JOIN_TAB *join_tab, bool end_of_records); +enum_nested_loop_state +sub_select(JOIN *join, JOIN_TAB *join_tab, bool end_of_records); +enum_nested_loop_state +sub_select_postjoin_aggr(JOIN *join, JOIN_TAB *join_tab, bool end_of_records); + +enum_nested_loop_state +end_send_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)), + bool end_of_records); +enum_nested_loop_state +end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)), + bool end_of_records); + + +class Semi_join_strategy_picker +{ +public: + /* Called when starting to build a new join prefix */ + virtual void set_empty() = 0; + + /* + Update internal state after another table has been added to the join + prefix + */ + virtual void set_from_prev(POSITION *prev) = 0; + + virtual bool check_qep(JOIN *join, + uint idx, + table_map remaining_tables, + const JOIN_TAB *new_join_tab, + double *record_count, + double *read_time, + table_map *handled_fanout, + sj_strategy_enum *strategy, + POSITION *loose_scan_pos) = 0; + + virtual void mark_used() = 0; + + virtual ~Semi_join_strategy_picker() = default; +}; + + +/* + Duplicate Weedout strategy optimization state +*/ + +class Duplicate_weedout_picker : public Semi_join_strategy_picker +{ + /* The first table that the strategy will need to handle */ + uint first_dupsweedout_table; + + /* + Tables that we will need to have in the prefix to do the weedout step + (all inner and all outer that the involved semi-joins are correlated with) + */ + table_map dupsweedout_tables; + + bool is_used; +public: + void set_empty() + { + dupsweedout_tables= 0; + first_dupsweedout_table= MAX_TABLES; + is_used= FALSE; + } + void set_from_prev(POSITION *prev); + + bool check_qep(JOIN *join, + uint idx, + table_map remaining_tables, + const JOIN_TAB *new_join_tab, + double *record_count, + double *read_time, + table_map *handled_fanout, + sj_strategy_enum *stratey, + POSITION *loose_scan_pos); + + void mark_used() { is_used= TRUE; } + friend void fix_semijoin_strategies_for_picked_join_order(JOIN *join); +}; + + +class Firstmatch_picker : public Semi_join_strategy_picker +{ + /* + Index of the first inner table that we intend to handle with this + strategy + */ + uint first_firstmatch_table; + /* + Tables that were not in the join prefix when we've started considering + FirstMatch strategy. + */ + table_map first_firstmatch_rtbl; + /* + Tables that need to be in the prefix before we can calculate the cost + of using FirstMatch strategy. + */ + table_map firstmatch_need_tables; + + bool is_used; + + bool in_firstmatch_prefix() { return (first_firstmatch_table != MAX_TABLES); } + void invalidate_firstmatch_prefix() { first_firstmatch_table= MAX_TABLES; } +public: + void set_empty() + { + invalidate_firstmatch_prefix(); + is_used= FALSE; + } + + void set_from_prev(POSITION *prev); + bool check_qep(JOIN *join, + uint idx, + table_map remaining_tables, + const JOIN_TAB *new_join_tab, + double *record_count, + double *read_time, + table_map *handled_fanout, + sj_strategy_enum *strategy, + POSITION *loose_scan_pos); + + void mark_used() { is_used= TRUE; } + friend void fix_semijoin_strategies_for_picked_join_order(JOIN *join); +}; + + +class LooseScan_picker : public Semi_join_strategy_picker +{ +public: + /* The first (i.e. driving) table we're doing loose scan for */ + uint first_loosescan_table; + /* + Tables that need to be in the prefix before we can calculate the cost + of using LooseScan strategy. + */ + table_map loosescan_need_tables; + + /* + keyno - Planning to do LooseScan on this key. If keyuse is NULL then + this is a full index scan, otherwise this is a ref+loosescan + scan (and keyno matches the KEUSE's) + MAX_KEY - Not doing a LooseScan + */ + uint loosescan_key; // final (one for strategy instance ) + uint loosescan_parts; /* Number of keyparts to be kept distinct */ + + bool is_used; + void set_empty() + { + first_loosescan_table= MAX_TABLES; + is_used= FALSE; + } + + void set_from_prev(POSITION *prev); + bool check_qep(JOIN *join, + uint idx, + table_map remaining_tables, + const JOIN_TAB *new_join_tab, + double *record_count, + double *read_time, + table_map *handled_fanout, + sj_strategy_enum *strategy, + POSITION *loose_scan_pos); + void mark_used() { is_used= TRUE; } + + friend class Loose_scan_opt; + friend void best_access_path(JOIN *join, + JOIN_TAB *s, + table_map remaining_tables, + const POSITION *join_positions, + uint idx, + bool disable_jbuf, + double record_count, + POSITION *pos, + POSITION *loose_scan_pos); + friend bool get_best_combination(JOIN *join); + friend int setup_semijoin_loosescan(JOIN *join); + friend void fix_semijoin_strategies_for_picked_join_order(JOIN *join); +}; + + +class Sj_materialization_picker : public Semi_join_strategy_picker +{ + bool is_used; + + /* The last inner table (valid once we're after it) */ + uint sjm_scan_last_inner; + /* + Tables that we need to have in the prefix to calculate the correct cost. + Basically, we need all inner tables and outer tables mentioned in the + semi-join's ON expression so we can correctly account for fanout. + */ + table_map sjm_scan_need_tables; + +public: + void set_empty() + { + sjm_scan_need_tables= 0; + sjm_scan_last_inner= 0; + is_used= FALSE; + } + void set_from_prev(POSITION *prev); + bool check_qep(JOIN *join, + uint idx, + table_map remaining_tables, + const JOIN_TAB *new_join_tab, + double *record_count, + double *read_time, + table_map *handled_fanout, + sj_strategy_enum *strategy, + POSITION *loose_scan_pos); + void mark_used() { is_used= TRUE; } + + friend void fix_semijoin_strategies_for_picked_join_order(JOIN *join); +}; + + +class Range_rowid_filter_cost_info; +class Rowid_filter; + + +/** + Information about a position of table within a join order. Used in join + optimization. +*/ +class POSITION +{ +public: + /* The table that's put into join order */ + JOIN_TAB *table; + + /* + The "fanout": number of output rows that will be produced (after + pushed down selection condition is applied) per each row combination of + previous tables. + */ + double records_read; + + /* The selectivity of the pushed down conditions */ + double cond_selectivity; + + /* + Cost accessing the table in course of the entire complete join execution, + i.e. cost of one access method use (e.g. 'range' or 'ref' scan ) times + number the access method will be invoked. + */ + double read_time; + + double prefix_record_count; + + /* Cost for the join prefix */ + double prefix_cost; + + /* + NULL - 'index' or 'range' or 'index_merge' or 'ALL' access is used. + Other - [eq_]ref[_or_null] access is used. Pointer to {t.keypart1 = expr} + */ + KEYUSE *key; + + /* Cardinality of current partial join ending with this position */ + double partial_join_cardinality; + + /* Info on splitting plan used at this position */ + SplM_plan_info *spl_plan; + + /* + If spl_plan is NULL the value of spl_pd_boundary is 0. Otherwise + spl_pd_boundary contains the bitmap of the table from the current + partial join ending at this position that starts the sub-sequence of + tables S from which no conditions are allowed to be used in the plan + spl_plan for the split table joined at this position. + */ + table_map spl_pd_boundary; + + /* Cost info for the range filter used at this position */ + Range_rowid_filter_cost_info *range_rowid_filter_info; + + /* If ref-based access is used: bitmap of tables this table depends on */ + table_map ref_depend_map; + + /* tables that may help best_access_path() to find a better key */ + table_map key_dependent; + /* + Bitmap of semi-join inner tables that are in the join prefix and for + which there's no provision for how to eliminate semi-join duplicates + they produce. + */ + table_map dups_producing_tables; + + table_map inner_tables_handled_with_other_sjs; + + Duplicate_weedout_picker dups_weedout_picker; + Firstmatch_picker firstmatch_picker; + LooseScan_picker loosescan_picker; + Sj_materialization_picker sjmat_picker; + + /* + Current optimization state: Semi-join strategy to be used for this + and preceding join tables. + + Join optimizer sets this for the *last* join_tab in the + duplicate-generating range. That is, in order to interpret this field, + one needs to traverse join->[best_]positions array from right to left. + When you see a join table with sj_strategy!= SJ_OPT_NONE, some other + field (depending on the strategy) tells how many preceding positions + this applies to. The values of covered_preceding_positions->sj_strategy + must be ignored. + */ + enum sj_strategy_enum sj_strategy; + + /* Type of join (EQ_REF, REF etc) */ + enum join_type type; + /* + Valid only after fix_semijoin_strategies_for_picked_join_order() call: + if sj_strategy!=SJ_OPT_NONE, this is the number of subsequent tables that + are covered by the specified semi-join strategy + */ + uint n_sj_tables; + + /* + TRUE <=> join buffering will be used. At the moment this is based on + *very* imprecise guesses made in best_access_path(). + */ + bool use_join_buffer; + POSITION(); +}; + +typedef Bounds_checked_array<Item_null_result*> Item_null_array; + +typedef struct st_rollup +{ + enum State { STATE_NONE, STATE_INITED, STATE_READY }; + State state; + Item_null_array null_items; + Ref_ptr_array *ref_pointer_arrays; + List<Item> *fields; +} ROLLUP; + + +class JOIN_TAB_RANGE: public Sql_alloc +{ +public: + JOIN_TAB *start; + JOIN_TAB *end; +}; + +class Pushdown_query; + +/** + @brief + Class to perform postjoin aggregation operations + + @details + The result records are obtained on the put_record() call. + The aggrgation process is determined by the write_func, it could be: + end_write Simply store all records in tmp table. + end_write_group Perform grouping using join->group_fields, + records are expected to be sorted. + end_update Perform grouping using the key generated on tmp + table. Input records aren't expected to be sorted. + Tmp table uses the heap engine + end_update_unique Same as above, but the engine is myisam. + + Lazy table initialization is used - the table will be instantiated and + rnd/index scan started on the first put_record() call. + +*/ + +class AGGR_OP :public Sql_alloc +{ +public: + JOIN_TAB *join_tab; + + AGGR_OP(JOIN_TAB *tab) : join_tab(tab), write_func(NULL) + {}; + + enum_nested_loop_state put_record() { return put_record(false); }; + /* + Send the result of operation further (to a next operation/client) + This function is called after all records were put into tmp table. + + @return return one of enum_nested_loop_state values. + */ + enum_nested_loop_state end_send(); + /** write_func setter */ + void set_write_func(Next_select_func new_write_func) + { + write_func= new_write_func; + } + +private: + /** Write function that would be used for saving records in tmp table. */ + Next_select_func write_func; + enum_nested_loop_state put_record(bool end_of_records); + bool prepare_tmp_table(); +}; + + +class JOIN :public Sql_alloc +{ +private: + JOIN(const JOIN &rhs); /**< not implemented */ + JOIN& operator=(const JOIN &rhs); /**< not implemented */ + +protected: + + /** + The subset of the state of a JOIN that represents an optimized query + execution plan. Allows saving/restoring different JOIN plans for the same + query. + */ + class Join_plan_state { + public: + DYNAMIC_ARRAY keyuse; /* Copy of the JOIN::keyuse array. */ + POSITION *best_positions; /* Copy of JOIN::best_positions */ + /* Copies of the JOIN_TAB::keyuse pointers for each JOIN_TAB. */ + KEYUSE **join_tab_keyuse; + /* Copies of JOIN_TAB::checked_keys for each JOIN_TAB. */ + key_map *join_tab_checked_keys; + SJ_MATERIALIZATION_INFO **sj_mat_info; + my_bool error; + public: + Join_plan_state(uint tables) : error(0) + { + keyuse.elements= 0; + keyuse.buffer= NULL; + keyuse.malloc_flags= 0; + best_positions= 0; /* To detect errors */ + error= my_multi_malloc(PSI_INSTRUMENT_ME, MYF(MY_WME), + &best_positions, + sizeof(*best_positions) * (tables + 1), + &join_tab_keyuse, + sizeof(*join_tab_keyuse) * tables, + &join_tab_checked_keys, + sizeof(*join_tab_checked_keys) * tables, + &sj_mat_info, + sizeof(sj_mat_info) * tables, + NullS) == 0; + } + Join_plan_state(JOIN *join); + ~Join_plan_state() + { + delete_dynamic(&keyuse); + my_free(best_positions); + } + }; + + /* Results of reoptimizing a JOIN via JOIN::reoptimize(). */ + enum enum_reopt_result { + REOPT_NEW_PLAN, /* there is a new reoptimized plan */ + REOPT_OLD_PLAN, /* no new improved plan can be found, use the old one */ + REOPT_ERROR, /* an irrecovarable error occurred during reoptimization */ + REOPT_NONE /* not yet reoptimized */ + }; + + /* Support for plan reoptimization with rewritten conditions. */ + enum_reopt_result reoptimize(Item *added_where, table_map join_tables, + Join_plan_state *save_to); + /* Choose a subquery plan for a table-less subquery. */ + bool choose_tableless_subquery_plan(); + void handle_implicit_grouping_with_window_funcs(); + +public: + void save_query_plan(Join_plan_state *save_to); + void reset_query_plan(); + void restore_query_plan(Join_plan_state *restore_from); + +public: + JOIN_TAB *join_tab, **best_ref; + + /* List of fields that aren't under an aggregate function */ + List<Item_field> non_agg_fields; + + JOIN_TAB **map2table; ///< mapping between table indexes and JOIN_TABs + List<JOIN_TAB_RANGE> join_tab_ranges; + + /* + Base tables participating in the join. After join optimization is done, the + tables are stored in the join order (but the only really important part is + that const tables are first). + */ + TABLE **table; + /** + The table which has an index that allows to produce the requried ordering. + A special value of 0x1 means that the ordering will be produced by + passing 1st non-const table to filesort(). NULL means no such table exists. + */ + TABLE *sort_by_table; + /* + Number of tables in the join. + (In MySQL, it is named 'tables' and is also the number of elements in + join->join_tab array. In MariaDB, the latter is not true, so we've renamed + the variable) + */ + uint table_count; + uint outer_tables; /**< Number of tables that are not inside semijoin */ + uint const_tables; + /* + Number of tables in the top join_tab array. Normally this matches + (join_tab_ranges.head()->end - join_tab_ranges.head()->start). + + We keep it here so that it is saved/restored with JOIN::restore_tmp. + */ + uint top_join_tab_count; + uint aggr_tables; ///< Number of post-join tmp tables + uint send_group_parts; + /* + This represents the number of items in ORDER BY *after* removing + all const items. This is computed before other optimizations take place, + such as removal of ORDER BY when it is a prefix of GROUP BY, for example: + GROUP BY a, b ORDER BY a + + This is used when deciding to send rows, by examining the correct number + of items in the group_fields list when ORDER BY was previously eliminated. + */ + uint with_ties_order_count; + /* + True if the query has GROUP BY. + (that is, if group_by != NULL. when DISTINCT is converted into GROUP BY, it + will set this, too. It is not clear why we need a separate var from + group_list) + */ + bool group; + bool need_distinct; + + /** + Indicates that grouping will be performed on the result set during + query execution. This field belongs to query execution. + + If 'sort_and_group' is set, then the optimizer is going to use on of + the following algorithms to resolve GROUP BY. + + - If one table, sort the table and then calculate groups on the fly. + - If more than one table, create a temporary table to hold the join, + sort it and then resolve group by on the fly. + + The 'on the fly' calculation is done in end_send_group() + + @see make_group_fields, alloc_group_fields, JOIN::exec, + setup_end_select_func + */ + bool sort_and_group; + bool first_record,full_join, no_field_update; + bool hash_join; + bool do_send_rows; + table_map const_table_map; + /** + Bitmap of semijoin tables that the current partial plan decided + to materialize and access by lookups + */ + table_map sjm_lookup_tables; + /** + Bitmap of semijoin tables that the chosen plan decided + to materialize to scan the results of materialization + */ + table_map sjm_scan_tables; + /* + Constant tables for which we have found a row (as opposed to those for + which we didn't). + */ + table_map found_const_table_map; + + /* Tables removed by table elimination. Set to 0 before the elimination. */ + table_map eliminated_tables; + /* + Bitmap of all inner tables from outer joins (set at start of + make_join_statistics) + */ + table_map outer_join; + /* Bitmap of tables used in the select list items */ + table_map select_list_used_tables; + /* Tables that has HA_NON_COMPARABLE_ROWID (does not support rowid) set */ + table_map not_usable_rowid_map; + /* Tables that have a possiblity to use EQ_ref */ + table_map eq_ref_tables; + + table_map allowed_top_level_tables; + ha_rows send_records,found_records,join_examined_rows, accepted_rows; + + /* + LIMIT for the JOIN operation. When not using aggregation or DISITNCT, this + is the same as select's LIMIT clause specifies. + Note that this doesn't take sql_calc_found_rows into account. + */ + ha_rows row_limit; + + /* + How many output rows should be produced after GROUP BY. + (if sql_calc_found_rows is used, LIMIT is ignored) + */ + ha_rows select_limit; + /* + Number of duplicate rows found in UNION. + */ + ha_rows duplicate_rows; + /** + Used to fetch no more than given amount of rows per one + fetch operation of server side cursor. + The value is checked in end_send and end_send_group in fashion, similar + to offset_limit_cnt: + - fetch_limit= HA_POS_ERROR if there is no cursor. + - when we open a cursor, we set fetch_limit to 0, + - on each fetch iteration we add num_rows to fetch to fetch_limit + NOTE: currently always HA_POS_ERROR. + */ + ha_rows fetch_limit; + + /* Finally picked QEP. This is result of join optimization */ + POSITION *best_positions; + POSITION *sort_positions; /* Temporary space used by greedy_search */ + POSITION *next_sort_position; /* Next free space in sort_positions */ + + Pushdown_query *pushdown_query; + JOIN_TAB *original_join_tab; + uint sort_space; + +/******* Join optimization state members start *******/ + /* + pointer - we're doing optimization for a semi-join materialization nest. + NULL - otherwise + */ + TABLE_LIST *emb_sjm_nest; + + /* Current join optimization state */ + POSITION *positions; + + /* + Bitmap of nested joins embedding the position at the end of the current + partial join (valid only during join optimizer run). + */ + nested_join_map cur_embedding_map; + + /* + Bitmap of inner tables of semi-join nests that have a proper subset of + their tables in the current join prefix. That is, of those semi-join + nests that have their tables both in and outside of the join prefix. + (Note: tables that are constants but have not been pulled out of semi-join + nests are not considered part of semi-join nests) + */ + table_map cur_sj_inner_tables; + + /* A copy of thd->variables.optimizer_prune_level */ + uint prune_level; + /* + If true, do extra heuristic pruning (enabled based on + optimizer_extra_pruning_depth) + */ + bool extra_heuristic_pruning; +#ifndef DBUG_OFF + void dbug_verify_sj_inner_tables(uint n_positions) const; + int dbug_join_tab_array_size; +#endif + + /* We also maintain a stack of join optimization states in * join->positions[] */ +/******* Join optimization state members end *******/ + + /* + Tables within complex firstmatch ranges (i.e. those where inner tables are + interleaved with outer tables). Join buffering cannot be used for these. + */ + table_map complex_firstmatch_tables; + + Next_select_func first_select; + /* + The cost of best complete join plan found so far during optimization, + after optimization phase - cost of picked join order (not taking into + account the changes made by test_if_skip_sort_order()). + */ + double best_read; + /* + Estimated result rows (fanout) of the join operation. If this is a subquery + that is reexecuted multiple times, this value includes the estiamted # of + reexecutions. This value is equal to the multiplication of all + join->positions[i].records_read of a JOIN. + */ + double join_record_count; + List<Item> *fields; + + /* Used only for FETCH ... WITH TIES to identify peers. */ + List<Cached_item> order_fields; + /* Used during GROUP BY operations to identify when a group has changed. */ + List<Cached_item> group_fields, group_fields_cache; + THD *thd; + Item_sum **sum_funcs, ***sum_funcs_end; + /** second copy of sumfuncs (for queries with 2 temporary tables */ + Item_sum **sum_funcs2, ***sum_funcs_end2; + Procedure *procedure; + Item *having; + Item *tmp_having; ///< To store having when processed temporary table + Item *having_history; ///< Store having for explain + ORDER *group_list_for_estimates; + bool having_is_correlated; + ulonglong select_options; + /* + Bitmap of allowed types of the join caches that + can be used for join operations + */ + uint allowed_join_cache_types; + bool allowed_semijoin_with_cache; + bool allowed_outer_join_with_cache; + /* Maximum level of the join caches that can be used for join operations */ + uint max_allowed_join_cache_level; + select_result *result; + TMP_TABLE_PARAM tmp_table_param; + MYSQL_LOCK *lock; + /// unit structure (with global parameters) for this select + SELECT_LEX_UNIT *unit; + /// select that processed + SELECT_LEX *select_lex; + /** + TRUE <=> optimizer must not mark any table as a constant table. + This is needed for subqueries in form "a IN (SELECT .. UNION SELECT ..): + when we optimize the select that reads the results of the union from a + temporary table, we must not mark the temp. table as constant because + 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; + + /** + This is set if SQL_CALC_ROWS was calculated by filesort() + and should be taken from the appropriate JOIN_TAB + */ + bool filesort_found_rows; + + bool subq_exit_fl; + + ROLLUP rollup; ///< Used with rollup + + bool mixed_implicit_grouping; + bool select_distinct; ///< Set if SELECT DISTINCT + /** + If we have the GROUP BY statement in the query, + but the group_list was emptied by optimizer, this + flag is TRUE. + It happens when fields in the GROUP BY are from + constant table + */ + bool group_optimized_away; + + /* + simple_xxxxx is set if ORDER/GROUP BY doesn't include any references + to other tables than the first non-constant table in the JOIN. + It's also set if ORDER/GROUP BY is empty. + Used for deciding for or against using a temporary table to compute + GROUP/ORDER BY. + */ + bool simple_order, simple_group; + + /* + ordered_index_usage is set if an ordered index access + should be used instead of a filesort when computing + ORDER/GROUP BY. + */ + enum + { + ordered_index_void, // No ordered index avail. + ordered_index_group_by, // Use index for GROUP BY + ordered_index_order_by // Use index for ORDER BY + } ordered_index_usage; + + /** + Is set only in case if we have a GROUP BY clause + and no ORDER BY after constant elimination of 'order'. + */ + bool no_order; + /** Is set if we have a GROUP BY and we have ORDER BY on a constant. */ + bool skip_sort_order; + + bool need_tmp; + bool hidden_group_fields; + /* TRUE if there was full cleunap of the JOIN */ + bool cleaned; + DYNAMIC_ARRAY keyuse; + Item::cond_result cond_value, having_value; + /** + Impossible where after reading const tables + (set in make_join_statistics()) + */ + bool impossible_where; + + /* + All fields used in the query processing. + + Initially this is a list of fields from the query's SQL text. + + Then, ORDER/GROUP BY and Window Function code add columns that need to + be saved to be available in the post-group-by context. These extra columns + are added to the front, because this->all_fields points to the suffix of + this list. + */ + List<Item> all_fields; + ///Above list changed to use temporary table + List<Item> tmp_all_fields1, tmp_all_fields2, tmp_all_fields3; + ///Part, shared with list above, emulate following list + List<Item> tmp_fields_list1, tmp_fields_list2, tmp_fields_list3; + + /* + The original field list as it was passed to mysql_select(). This refers + to select_lex->item_list. + CAUTION: this list is a suffix of this->all_fields list, that is, it shares + elements with that list! + */ + List<Item> &fields_list; + List<Item> procedure_fields_list; + int error; + + ORDER *order, *group_list, *proc_param; //hold parameters of mysql_select + COND *conds; // ---"--- + Item *conds_history; // store WHERE for explain + COND *outer_ref_cond; ///<part of conds containing only outer references + COND *pseudo_bits_cond; // part of conds containing special bita + TABLE_LIST *tables_list; ///<hold 'tables' parameter of mysql_select + List<TABLE_LIST> *join_list; ///< list of joined tables in reverse order + COND_EQUAL *cond_equal; + COND_EQUAL *having_equal; + /* + Constant codition computed during optimization, but evaluated during + join execution. Typically expensive conditions that should not be + evaluated at optimization time. + */ + Item *exec_const_cond; + /* + Constant ORDER and/or GROUP expressions that contain subqueries. Such + expressions need to evaluated to verify that the subquery indeed + returns a single row. The evaluation of such expressions is delayed + until query execution. + */ + List<Item> exec_const_order_group_cond; + SQL_SELECT *select; ///<created in optimisation phase + JOIN_TAB *return_tab; ///<used only for outer joins + + /* + Used pointer reference for this select. + select_lex->ref_pointer_array contains five "slices" of the same length: + |========|========|========|========|========| + ref_ptrs items0 items1 items2 items3 + */ + Ref_ptr_array ref_ptrs; + // Copy of the initial slice above, to be used with different lists + Ref_ptr_array items0, items1, items2, items3; + // Used by rollup, to restore ref_ptrs after overwriting it. + Ref_ptr_array current_ref_ptrs; + + const char *zero_result_cause; ///< not 0 if exec must return zero result + + bool union_part; ///< this subselect is part of union + + enum join_optimization_state { NOT_OPTIMIZED=0, + OPTIMIZATION_IN_PROGRESS=1, + OPTIMIZATION_PHASE_1_DONE=2, + OPTIMIZATION_DONE=3}; + // state of JOIN optimization + enum join_optimization_state optimization_state; + bool initialized; ///< flag to avoid double init_execution calls + + Explain_select *explain; + + enum { QEP_NOT_PRESENT_YET, QEP_AVAILABLE, QEP_DELETED} have_query_plan; + + // if keep_current_rowid=true, whether they should be saved in temporary table + bool tmp_table_keep_current_rowid; + + /* + Additional WHERE and HAVING predicates to be considered for IN=>EXISTS + subquery transformation of a JOIN object. + */ + Item *in_to_exists_where; + Item *in_to_exists_having; + + /* Temporary tables used to weed-out semi-join duplicates */ + List<TABLE> sj_tmp_tables; + /* SJM nests that are executed with SJ-Materialization strategy */ + List<SJ_MATERIALIZATION_INFO> sjm_info_list; + + /** TRUE <=> ref_pointer_array is set to items3. */ + bool set_group_rpa; + /** Exec time only: TRUE <=> current group has been sent */ + bool group_sent; + /** + TRUE if the query contains an aggregate function but has no GROUP + BY clause. + */ + bool implicit_grouping; + + bool with_two_phase_optimization; + + /* Saved execution plan for this join */ + Join_plan_state *save_qep; + /* Info on splittability of the table materialized by this plan*/ + SplM_opt_info *spl_opt_info; + /* Contains info on keyuses usable for splitting */ + Dynamic_array<KEYUSE_EXT> *ext_keyuses_for_splitting; + + JOIN_TAB *sort_and_group_aggr_tab; + /* + Flag is set to true if select_lex was found to be degenerated before + the optimize_cond() call in JOIN::optimize_inner() method. + */ + bool is_orig_degenerated; + + JOIN(THD *thd_arg, List<Item> &fields_arg, ulonglong select_options_arg, + select_result *result_arg) + :fields_list(fields_arg) + { + init(thd_arg, fields_arg, select_options_arg, result_arg); + } + + void init(THD *thd_arg, List<Item> &fields_arg, ulonglong select_options_arg, + select_result *result_arg); + + /* True if the plan guarantees that it will be returned zero or one row */ + bool only_const_tables() { return const_tables == table_count; } + /* Number of tables actually joined at the top level */ + uint exec_join_tab_cnt() { return tables_list ? top_join_tab_count : 0; } + + /* + Number of tables in the join which also includes the temporary tables + created for GROUP BY, DISTINCT , WINDOW FUNCTION etc. + */ + uint total_join_tab_cnt() + { + return exec_join_tab_cnt() + aggr_tables - 1; + } + + int prepare(TABLE_LIST *tables, COND *conds, uint og_num, ORDER *order, + bool skip_order_by, ORDER *group, Item *having, + ORDER *proc_param, SELECT_LEX *select, SELECT_LEX_UNIT *unit); + bool prepare_stage2(); + int optimize(); + int optimize_inner(); + int optimize_stage2(); + bool build_explain(); + int reinit(); + int init_execution(); + void exec(); + + void exec_inner(); + bool prepare_result(List<Item> **columns_list); + int destroy(); + void restore_tmp(); + bool alloc_func_list(); + bool flatten_subqueries(); + bool optimize_unflattened_subqueries(); + bool optimize_constant_subqueries(); + bool make_range_rowid_filters(); + bool init_range_rowid_filters(); + bool make_sum_func_list(List<Item> &all_fields, List<Item> &send_fields, + bool before_group_by); + + /// Initialzes a slice, see comments for ref_ptrs above. + Ref_ptr_array ref_ptr_array_slice(size_t slice_num) + { + size_t slice_sz= select_lex->ref_pointer_array.size() / 5U; + DBUG_ASSERT(select_lex->ref_pointer_array.size() % 5 == 0); + DBUG_ASSERT(slice_num < 5U); + return Ref_ptr_array(&select_lex->ref_pointer_array[slice_num * slice_sz], + slice_sz); + } + + /** + Overwrites one slice with the contents of another slice. + In the normal case, dst and src have the same size(). + However: the rollup slices may have smaller size than slice_sz. + */ + void copy_ref_ptr_array(Ref_ptr_array dst_arr, Ref_ptr_array src_arr) + { + DBUG_ASSERT(dst_arr.size() >= src_arr.size()); + if (src_arr.size() == 0) + return; + + void *dest= dst_arr.array(); + const void *src= src_arr.array(); + memcpy(dest, src, src_arr.size() * src_arr.element_size()); + } + + /// Overwrites 'ref_ptrs' and remembers the the source as 'current'. + void set_items_ref_array(Ref_ptr_array src_arr) + { + copy_ref_ptr_array(ref_ptrs, src_arr); + current_ref_ptrs= src_arr; + } + + /// Initializes 'items0' and remembers that it is 'current'. + void init_items_ref_array() + { + items0= ref_ptr_array_slice(1); + copy_ref_ptr_array(items0, ref_ptrs); + current_ref_ptrs= items0; + } + + bool rollup_init(); + bool rollup_process_const_fields(); + bool rollup_make_fields(List<Item> &all_fields, List<Item> &fields, + Item_sum ***func); + int rollup_send_data(uint idx); + int rollup_write_data(uint idx, TMP_TABLE_PARAM *tmp_table_param, TABLE *table); + void join_free(); + /** Cleanup this JOIN, possibly for reuse */ + void cleanup(bool full); + void clear(table_map *cleared_tables); + void inline clear_sum_funcs(); + bool send_row_on_empty_set() + { + return (do_send_rows && implicit_grouping && !group_optimized_away && + having_value != Item::COND_FALSE); + } + bool empty_result() { return (zero_result_cause && !implicit_grouping); } + bool change_result(select_result *new_result, select_result *old_result); + bool is_top_level_join() const + { + return (unit == &thd->lex->unit && (unit->fake_select_lex == 0 || + select_lex == unit->fake_select_lex)); + } + void cache_const_exprs(); + inline table_map all_tables_map() + { + return (table_map(1) << table_count) - 1; + } + void drop_unused_derived_keys(); + bool get_best_combination(); + bool add_sorting_to_table(JOIN_TAB *tab, ORDER *order); + inline void eval_select_list_used_tables(); + /* + Return the table for which an index scan can be used to satisfy + the sort order needed by the ORDER BY/(implicit) GROUP BY clause + */ + JOIN_TAB *get_sort_by_join_tab() + { + return (need_tmp || !sort_by_table || skip_sort_order || + ((group || tmp_table_param.sum_func_count) && !group_list)) ? + NULL : join_tab+const_tables; + } + bool setup_subquery_caches(); + bool shrink_join_buffers(JOIN_TAB *jt, + ulonglong curr_space, + ulonglong needed_space); + void set_allowed_join_cache_types(); + bool is_allowed_hash_join_access() + { + return MY_TEST(allowed_join_cache_types & JOIN_CACHE_HASHED_BIT) && + max_allowed_join_cache_level > JOIN_CACHE_HASHED_BIT; + } + /* + Check if we need to create a temporary table. + This has to be done if all tables are not already read (const tables) + and one of the following conditions holds: + - We are using DISTINCT (simple distinct's are already optimized away) + - We are using an ORDER BY or GROUP BY on fields not in the first table + - We are using different ORDER BY and GROUP BY orders + - The user wants us to buffer the result. + - We are using WINDOW functions. + When the WITH ROLLUP modifier is present, we cannot skip temporary table + creation for the DISTINCT clause just because there are only const tables. + */ + bool test_if_need_tmp_table() + { + return ((const_tables != table_count && + ((select_distinct || !simple_order || !simple_group) || + (group_list && order) || + MY_TEST(select_options & OPTION_BUFFER_RESULT))) || + (rollup.state != ROLLUP::STATE_NONE && select_distinct) || + select_lex->have_window_funcs()); + } + bool choose_subquery_plan(table_map join_tables); + void get_partial_cost_and_fanout(int end_tab_idx, + table_map filter_map, + double *read_time_arg, + double *record_count_arg); + void get_prefix_cost_and_fanout(uint n_tables, + double *read_time_arg, + double *record_count_arg); + double get_examined_rows(); + /* defined in opt_subselect.cc */ + bool transform_max_min_subquery(); + /* True if this JOIN is a subquery under an IN predicate. */ + bool is_in_subquery() + { + return (unit->item && unit->item->is_in_predicate()); + } + bool save_explain_data(Explain_query *output, bool can_overwrite, + bool need_tmp_table, bool need_order, bool distinct); + int save_explain_data_intern(Explain_query *output, bool need_tmp_table, + bool need_order, bool distinct, + const char *message); + JOIN_TAB *first_breadth_first_tab() { return join_tab; } + bool check_two_phase_optimization(THD *thd); + bool inject_cond_into_where(Item *injected_cond); + bool check_for_splittable_materialized(); + void add_keyuses_for_splitting(); + bool inject_best_splitting_cond(table_map remaining_tables); + bool fix_all_splittings_in_plan(); + bool inject_splitting_cond_for_all_tables_with_split_opt(); + void make_notnull_conds_for_range_scans(); + + bool transform_in_predicates_into_in_subq(THD *thd); + + bool optimize_upper_rownum_func(); + void calc_allowed_top_level_tables(SELECT_LEX *lex); + table_map get_allowed_nj_tables(uint idx); + +private: + /** + Create a temporary table to be used for processing DISTINCT/ORDER + BY/GROUP BY. + + @note Will modify JOIN object wrt sort/group attributes + + @param tab the JOIN_TAB object to attach created table to + @param tmp_table_fields List of items that will be used to define + column types of the table. + @param tmp_table_group Group key to use for temporary table, NULL if none. + @param save_sum_fields If true, do not replace Item_sum items in + @c tmp_fields list with Item_field items referring + to fields in temporary table. + + @returns false on success, true on failure + */ + bool create_postjoin_aggr_table(JOIN_TAB *tab, List<Item> *tmp_table_fields, + ORDER *tmp_table_group, + bool save_sum_fields, + bool distinct, + bool keep_row_ordermake); + /** + Optimize distinct when used on a subset of the tables. + + E.g.,: SELECT DISTINCT t1.a FROM t1,t2 WHERE t1.b=t2.b + In this case we can stop scanning t2 when we have found one t1.a + */ + void optimize_distinct(); + + void cleanup_item_list(List<Item> &items) const; + bool add_having_as_table_cond(JOIN_TAB *tab); + bool make_aggr_tables_info(); + bool add_fields_for_current_rowid(JOIN_TAB *cur, List<Item> *fields); + void free_pushdown_handlers(List<TABLE_LIST>& join_list); + void init_join_cache_and_keyread(); + bool transform_in_predicates_into_equalities(THD *thd); + bool transform_all_conds_and_on_exprs(THD *thd, + Item_transformer transformer); + bool transform_all_conds_and_on_exprs_in_join_list(THD *thd, + List<TABLE_LIST> *join_list, + Item_transformer transformer); +}; + +enum enum_with_bush_roots { WITH_BUSH_ROOTS, WITHOUT_BUSH_ROOTS}; +enum enum_with_const_tables { WITH_CONST_TABLES, WITHOUT_CONST_TABLES}; + +JOIN_TAB *first_linear_tab(JOIN *join, + enum enum_with_bush_roots include_bush_roots, + enum enum_with_const_tables const_tbls); +JOIN_TAB *next_linear_tab(JOIN* join, JOIN_TAB* tab, + enum enum_with_bush_roots include_bush_roots); + +JOIN_TAB *first_top_level_tab(JOIN *join, enum enum_with_const_tables with_const); +JOIN_TAB *next_top_level_tab(JOIN *join, JOIN_TAB *tab); + +typedef struct st_select_check { + uint const_ref,reg_ref; +} SELECT_CHECK; + +extern const char *join_type_str[]; + +/* Extern functions in sql_select.cc */ +void count_field_types(SELECT_LEX *select_lex, TMP_TABLE_PARAM *param, + List<Item> &fields, bool reset_with_sum_func); +bool setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param, + Ref_ptr_array ref_pointer_array, + List<Item> &new_list1, List<Item> &new_list2, + uint elements, List<Item> &fields); +void copy_fields(TMP_TABLE_PARAM *param); +bool copy_funcs(Item **func_ptr, const THD *thd); +uint find_shortest_key(TABLE *table, const key_map *usable_keys); +bool is_indexed_agg_distinct(JOIN *join, List<Item_field> *out_args); + +/* functions from opt_sum.cc */ +bool simple_pred(Item_func *func_item, Item **args, bool *inv_order); +int opt_sum_query(THD* thd, + List<TABLE_LIST> &tables, List<Item> &all_fields, COND *conds); + +/* from sql_delete.cc, used by opt_range.cc */ +extern "C" int refpos_order_cmp(void* arg, const void *a,const void *b); + +/** class to copying an field/item to a key struct */ + +class store_key :public Sql_alloc +{ +public: + bool null_key; /* TRUE <=> the value of the key has a null part */ + enum store_key_result { STORE_KEY_OK, STORE_KEY_FATAL, STORE_KEY_CONV }; + enum Type { FIELD_STORE_KEY, ITEM_STORE_KEY, CONST_ITEM_STORE_KEY }; + store_key(THD *thd, Field *field_arg, uchar *ptr, uchar *null, uint length) + :null_key(0), null_ptr(null), err(0) + { + to_field=field_arg->new_key_field(thd->mem_root, field_arg->table, + ptr, length, null, 1); + } + store_key(store_key &arg) + :Sql_alloc(), null_key(arg.null_key), to_field(arg.to_field), + null_ptr(arg.null_ptr), err(arg.err) + + {} + virtual ~store_key() = default; /** Not actually needed */ + virtual enum Type type() const=0; + virtual const char *name() const=0; + virtual bool store_key_is_const() { return false; } + + /** + @brief sets ignore truncation warnings mode and calls the real copy method + + @details this function makes sure truncation warnings when preparing the + key buffers don't end up as errors (because of an enclosing INSERT/UPDATE). + */ + enum store_key_result copy(THD *thd) + { + enum_check_fields org_count_cuted_fields= thd->count_cuted_fields; + Use_relaxed_field_copy urfc(to_field->table->in_use); + + /* If needed, perform CharsetNarrowing for making ref access lookup keys. */ + Utf8_narrow do_narrow(to_field, do_cset_narrowing); + + store_key_result result= copy_inner(); + + do_narrow.stop(); + + thd->count_cuted_fields= org_count_cuted_fields; + return result; + } + + protected: + Field *to_field; // Store data here + uchar *null_ptr; + uchar err; + + /* + This is set to true if we need to do Charset Narrowing when making a lookup + key. + */ + bool do_cset_narrowing= false; + + virtual enum store_key_result copy_inner()=0; +}; + + +class store_key_field: public store_key +{ + Copy_field copy_field; + const char *field_name; + public: + store_key_field(THD *thd, Field *to_field_arg, uchar *ptr, + uchar *null_ptr_arg, + uint length, Field *from_field, const char *name_arg) + :store_key(thd, to_field_arg,ptr, + null_ptr_arg ? null_ptr_arg : from_field->maybe_null() ? &err + : (uchar*) 0, length), field_name(name_arg) + { + if (to_field) + { + copy_field.set(to_field,from_field,0); + setup_charset_narrowing(); + } + } + + enum Type type() const override { return FIELD_STORE_KEY; } + const char *name() const override { return field_name; } + + void change_source_field(Item_field *fld_item) + { + copy_field.set(to_field, fld_item->field, 0); + field_name= fld_item->full_name(); + setup_charset_narrowing(); + } + + /* Setup CharsetNarrowing if necessary */ + void setup_charset_narrowing() + { + do_cset_narrowing= + Utf8_narrow::should_do_narrowing(copy_field.to_field, + copy_field.from_field->charset()); + } + + protected: + enum store_key_result copy_inner() override + { + TABLE *table= copy_field.to_field->table; + MY_BITMAP *old_map= dbug_tmp_use_all_columns(table, + &table->write_set); + + /* + It looks like the next statement is needed only for a simplified + hash function over key values used now in BNLH join. + When the implementation of this function will be replaced for a proper + full version this statement probably should be removed. + */ + bzero(copy_field.to_ptr,copy_field.to_length); + + copy_field.do_copy(©_field); + dbug_tmp_restore_column_map(&table->write_set, old_map); + null_key= to_field->is_null(); + return err != 0 ? STORE_KEY_FATAL : STORE_KEY_OK; + } +}; + + +class store_key_item :public store_key +{ + protected: + Item *item; + /* + Flag that forces usage of save_val() method which save value of the + item instead of save_in_field() method which saves result. + */ + bool use_value; +public: + store_key_item(THD *thd, Field *to_field_arg, uchar *ptr, + uchar *null_ptr_arg, uint length, Item *item_arg, bool val) + :store_key(thd, to_field_arg, ptr, + null_ptr_arg ? null_ptr_arg : item_arg->maybe_null() ? + &err : (uchar*) 0, length), item(item_arg), use_value(val) + { + /* Setup CharsetNarrowing to be done if necessary */ + do_cset_narrowing= + Utf8_narrow::should_do_narrowing(to_field, + item->collation.collation); + } + store_key_item(store_key &arg, Item *new_item, bool val) + :store_key(arg), item(new_item), use_value(val) + {} + + + enum Type type() const override { return ITEM_STORE_KEY; } + const char *name() const override { return "func"; } + + protected: + enum store_key_result copy_inner() override + { + TABLE *table= to_field->table; + MY_BITMAP *old_map= dbug_tmp_use_all_columns(table, + &table->write_set); + int res= FALSE; + + /* + It looks like the next statement is needed only for a simplified + hash function over key values used now in BNLH join. + When the implementation of this function will be replaced for a proper + full version this statement probably should be removed. + */ + to_field->reset(); + + if (use_value) + item->save_val(to_field); + else + res= item->save_in_field(to_field, 1); + /* + Item::save_in_field() may call Item::val_xxx(). And if this is a subquery + we need to check for errors executing it and react accordingly + */ + if (!res && table->in_use->is_error()) + res= 1; /* STORE_KEY_FATAL */ + dbug_tmp_restore_column_map(&table->write_set, old_map); + null_key= to_field->is_null() || item->null_value; + return ((err != 0 || res < 0 || res > 2) ? STORE_KEY_FATAL : + (store_key_result) res); + } +}; + + +class store_key_const_item :public store_key_item +{ + bool inited; +public: + store_key_const_item(THD *thd, Field *to_field_arg, uchar *ptr, + uchar *null_ptr_arg, uint length, + Item *item_arg) + :store_key_item(thd, to_field_arg, ptr, + null_ptr_arg ? null_ptr_arg : item_arg->maybe_null() ? + &err : (uchar*) 0, length, item_arg, FALSE), inited(0) + { + } + store_key_const_item(store_key &arg, Item *new_item) + :store_key_item(arg, new_item, FALSE), inited(0) + {} + + enum Type type() const override { return CONST_ITEM_STORE_KEY; } + const char *name() const override { return "const"; } + bool store_key_is_const() override { return true; } + +protected: + enum store_key_result copy_inner() override + { + int res; + if (!inited) + { + inited=1; + TABLE *table= to_field->table; + MY_BITMAP *old_map= dbug_tmp_use_all_columns(table, + &table->write_set); + if ((res= item->save_in_field(to_field, 1))) + { + if (!err) + err= res < 0 ? 1 : res; /* 1=STORE_KEY_FATAL */ + } + /* + Item::save_in_field() may call Item::val_xxx(). And if this is a subquery + we need to check for errors executing it and react accordingly + */ + if (!err && to_field->table->in_use->is_error()) + err= 1; /* STORE_KEY_FATAL */ + dbug_tmp_restore_column_map(&table->write_set, old_map); + } + null_key= to_field->is_null() || item->null_value; + return (err > 2 ? STORE_KEY_FATAL : (store_key_result) err); + } +}; + +void best_access_path(JOIN *join, JOIN_TAB *s, + table_map remaining_tables, + const POSITION *join_positions, uint idx, + bool disable_jbuf, double record_count, + POSITION *pos, POSITION *loose_scan_pos); +bool cp_buffer_from_ref(THD *thd, TABLE *table, TABLE_REF *ref); +bool error_if_full_join(JOIN *join); +int report_error(TABLE *table, int error); +int safe_index_read(JOIN_TAB *tab); +int get_quick_record(SQL_SELECT *select); +int setup_order(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables, + List<Item> &fields, List <Item> &all_fields, ORDER *order, + bool from_window_spec= false); +int setup_group(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables, + List<Item> &fields, List<Item> &all_fields, ORDER *order, + bool *hidden_group_fields, bool from_window_spec= false); +bool fix_inner_refs(THD *thd, List<Item> &all_fields, SELECT_LEX *select, + Ref_ptr_array ref_pointer_array); +int join_read_key2(THD *thd, struct st_join_table *tab, TABLE *table, + struct st_table_ref *table_ref); + +bool handle_select(THD *thd, LEX *lex, select_result *result, + ulonglong setup_tables_done_option); +bool mysql_select(THD *thd, TABLE_LIST *tables, List<Item> &list, + COND *conds, uint og_num, ORDER *order, ORDER *group, + Item *having, ORDER *proc_param, ulonglong select_type, + select_result *result, SELECT_LEX_UNIT *unit, + SELECT_LEX *select_lex); +void free_underlaid_joins(THD *thd, SELECT_LEX *select); +bool mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, + select_result *result); + +/* + General routine to change field->ptr of a NULL-terminated array of Field + objects. Useful when needed to call val_int, val_str or similar and the + field data is not in table->record[0] but in some other structure. + set_key_field_ptr changes all fields of an index using a key_info object. + All methods presume that there is at least one field to change. +*/ + + +class Virtual_tmp_table: public TABLE +{ + /** + Destruct collected fields. This method can be called on errors, + when we could not make the virtual temporary table completely, + e.g. when some of the fields could not be created or added. + + This is needed to avoid memory leaks, as some fields can be BLOB + variants and thus can have String onboard. Strings must be destructed + as they store data on the heap (not on MEM_ROOT). + */ + void destruct_fields() + { + for (uint i= 0; i < s->fields; i++) + { + field[i]->free(); + delete field[i]; // to invoke the field destructor + } + s->fields= 0; // safety + } + +protected: + /** + The number of the fields that are going to be in the table. + We remember the number of the fields at init() time, and + at open() we check that all of the fields were really added. + */ + uint m_alloced_field_count; + + /** + Setup field pointers and null-bit pointers. + */ + void setup_field_pointers(); + +public: + /** + Create a new empty virtual temporary table on the thread mem_root. + After creation, the caller must: + - call init() + - populate the table with new fields using add(). + - call open(). + @param thd - Current thread. + */ + static void *operator new(size_t size, THD *thd) throw(); + static void operator delete(void *ptr, size_t size) { TRASH_FREE(ptr, size); } + static void operator delete(void *, THD *) throw(){} + + Virtual_tmp_table(THD *thd) : m_alloced_field_count(0) + { + reset(); + temp_pool_slot= MY_BIT_NONE; + in_use= thd; + copy_blobs= true; + alias.set("", 0, &my_charset_bin); + } + + ~Virtual_tmp_table() + { + if (s) + destruct_fields(); + } + + /** + Allocate components for the given number of fields. + - fields[] + - s->blob_fields[], + - bitmaps: def_read_set, def_write_set, tmp_set, eq_join_set, cond_set. + @param field_count - The number of fields we plan to add to the table. + @returns false - on success. + @returns true - on error. + */ + bool init(uint field_count); + + /** + Add one Field to the end of the field array, update members: + s->reclength, s->fields, s->blob_fields, s->null_fuelds. + */ + bool add(Field *new_field) + { + DBUG_ASSERT(s->fields < m_alloced_field_count); + new_field->init(this); + field[s->fields]= new_field; + s->reclength+= new_field->pack_length(); + if (!(new_field->flags & NOT_NULL_FLAG)) + s->null_fields++; + if (new_field->flags & BLOB_FLAG) + { + // Note, s->blob_fields was incremented in Field_blob::Field_blob + DBUG_ASSERT(s->blob_fields); + DBUG_ASSERT(s->blob_fields <= m_alloced_field_count); + s->blob_field[s->blob_fields - 1]= s->fields; + } + new_field->field_index= s->fields++; + return false; + } + + /** + Add fields from a Spvar_definition list + @returns false - on success. + @returns true - on error. + */ + bool add(List<Spvar_definition> &field_list); + + /** + Open a virtual table for read/write: + - Setup end markers in TABLE::field and TABLE_SHARE::blob_fields, + - Allocate a buffer in TABLE::record[0]. + - Set field pointers (Field::ptr, Field::null_pos, Field::null_bit) to + the allocated record. + This method is called when all of the fields have been added to the table. + After calling this method the table is ready for read and write operations. + @return false - on success + @return true - on error (e.g. could not allocate the record buffer). + */ + bool open(); + + void set_all_fields_to_null() + { + for (uint i= 0; i < s->fields; i++) + field[i]->set_null(); + } + /** + Set all fields from a compatible item list. + The number of fields in "this" must be equal to the number + of elements in "value". + */ + bool sp_set_all_fields_from_item_list(THD *thd, List<Item> &items); + + /** + Set all fields from a compatible item. + The number of fields in "this" must be the same with the number + of elements in "value". + */ + bool sp_set_all_fields_from_item(THD *thd, Item *value); + + /** + Find a ROW element index by its name + Assumes that "this" is used as a storage for a ROW-type SP variable. + @param [OUT] idx - the index of the found field is returned here + @param [IN] field_name - find a field with this name + @return true - on error (the field was not found) + @return false - on success (idx[0] was set to the field index) + */ + bool sp_find_field_by_name(uint *idx, const LEX_CSTRING &name) const; + + /** + Find a ROW element index by its name. + If the element is not found, and error is issued. + @param [OUT] idx - the index of the found field is returned here + @param [IN] var_name - the name of the ROW variable (for error reporting) + @param [IN] field_name - find a field with this name + @return true - on error (the field was not found) + @return false - on success (idx[0] was set to the field index) + */ + bool sp_find_field_by_name_or_error(uint *idx, + const LEX_CSTRING &var_name, + const LEX_CSTRING &field_name) const; +}; + + +/** + Create a reduced TABLE object with properly set up Field list from a + list of field definitions. + + The created table doesn't have a table handler associated with + it, has no keys, no group/distinct, no copy_funcs array. + The sole purpose of this TABLE object is to use the power of Field + class to read/write data to/from table->record[0]. Then one can store + the record in any container (RB tree, hash, etc). + The table is created in THD mem_root, so are the table's fields. + Consequently, if you don't BLOB fields, you don't need to free it. + + @param thd connection handle + @param field_list list of column definitions + + @return + 0 if out of memory, or a + TABLE object ready for read and write in case of success +*/ + +inline Virtual_tmp_table * +create_virtual_tmp_table(THD *thd, List<Spvar_definition> &field_list) +{ + Virtual_tmp_table *table; + if (!(table= new(thd) Virtual_tmp_table(thd))) + return NULL; + + /* + If "simulate_create_virtual_tmp_table_out_of_memory" debug option + is enabled, we now enable "simulate_out_of_memory". This effectively + makes table->init() fail on OOM inside multi_alloc_root(). + This is done to test that ~Virtual_tmp_table() called from the "delete" + below correcly handles OOM. + */ + DBUG_EXECUTE_IF("simulate_create_virtual_tmp_table_out_of_memory", + DBUG_SET("+d,simulate_out_of_memory");); + + if (table->init(field_list.elements) || + table->add(field_list) || + table->open()) + { + delete table; + return NULL; + } + return table; +} + + +/** + Create a new virtual temporary table consisting of a single field. + SUM(DISTINCT expr) and similar numeric aggregate functions use this. + @param thd - Current thread + @param field - The field that will be added into the table. + @return NULL - On error. + @return !NULL - A pointer to the created table that is ready + for read and write. +*/ +inline TABLE * +create_virtual_tmp_table(THD *thd, Field *field) +{ + Virtual_tmp_table *table; + DBUG_ASSERT(field); + if (!(table= new(thd) Virtual_tmp_table(thd))) + return NULL; + if (table->init(1) || + table->add(field) || + table->open()) + { + delete table; + return NULL; + } + return table; +} + + +int test_if_item_cache_changed(List<Cached_item> &list); +int join_init_read_record(JOIN_TAB *tab); +void set_position(JOIN *join,uint idx,JOIN_TAB *table,KEYUSE *key); +inline Item * and_items(THD *thd, Item* cond, Item *item) +{ + return (cond ? (new (thd->mem_root) Item_cond_and(thd, cond, item)) : item); +} +inline Item * or_items(THD *thd, Item* cond, Item *item) +{ + return (cond ? (new (thd->mem_root) Item_cond_or(thd, cond, item)) : item); +} +bool choose_plan(JOIN *join, table_map join_tables); +void optimize_wo_join_buffering(JOIN *join, uint first_tab, uint last_tab, + table_map last_remaining_tables, + bool first_alt, uint no_jbuf_before, + double *outer_rec_count, double *reopt_cost); +Item_equal *find_item_equal(COND_EQUAL *cond_equal, Field *field, + bool *inherited_fl); +extern bool test_if_ref(Item *, + Item_field *left_item,Item *right_item); + +inline bool optimizer_flag(const THD *thd, ulonglong flag) +{ + return (thd->variables.optimizer_switch & flag); +} + +/* +int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly, + SELECT_LEX *select_lex, uint8 select_options); +*/ + +uint get_index_for_order(ORDER *order, TABLE *table, SQL_SELECT *select, + ha_rows limit, ha_rows *scanned_limit, + bool *need_sort, bool *reverse); +ORDER *simple_remove_const(ORDER *order, COND *where); +bool const_expression_in_where(COND *cond, Item *comp_item, + Field *comp_field= NULL, + Item **const_item= NULL); +bool cond_is_datetime_is_null(Item *cond); +bool cond_has_datetime_is_null(Item *cond); + +/* Table elimination entry point function */ +void eliminate_tables(JOIN *join); + +/* Index Condition Pushdown entry point function */ +void push_index_cond(JOIN_TAB *tab, uint keyno); + +#define OPT_LINK_EQUAL_FIELDS 1 + +/* EXPLAIN-related utility functions */ +int print_explain_message_line(select_result_sink *result, + uint8 options, bool is_analyze, + uint select_number, + const char *select_type, + ha_rows *rows, + const char *message); +void explain_append_mrr_info(QUICK_RANGE_SELECT *quick, String *res); +int append_possible_keys(MEM_ROOT *alloc, String_list &list, TABLE *table, + key_map possible_keys); +void unpack_to_base_table_fields(TABLE *table); + +/**************************************************************************** + Temporary table support for SQL Runtime + ***************************************************************************/ + +#define STRING_TOTAL_LENGTH_TO_PACK_ROWS 128 +#define AVG_STRING_LENGTH_TO_PACK_ROWS 64 +#define RATIO_TO_PACK_ROWS 2 +#define MIN_STRING_LENGTH_TO_PACK_ROWS 10 + +void calc_group_buffer(TMP_TABLE_PARAM *param, ORDER *group); +TABLE *create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields, + ORDER *group, bool distinct, bool save_sum_fields, + ulonglong select_options, ha_rows rows_limit, + const LEX_CSTRING *alias, bool do_not_open=FALSE, + bool keep_row_order= FALSE); +TABLE *create_tmp_table_for_schema(THD *thd, TMP_TABLE_PARAM *param, + const ST_SCHEMA_TABLE &schema_table, + longlong select_options, + const LEX_CSTRING &alias, + bool do_not_open, bool keep_row_order); + +void free_tmp_table(THD *thd, TABLE *entry); +bool create_internal_tmp_table_from_heap(THD *thd, TABLE *table, + TMP_ENGINE_COLUMNDEF *start_recinfo, + TMP_ENGINE_COLUMNDEF **recinfo, + int error, bool ignore_last_dupp_key_error, + bool *is_duplicate); +bool create_internal_tmp_table(TABLE *table, KEY *keyinfo, + TMP_ENGINE_COLUMNDEF *start_recinfo, + TMP_ENGINE_COLUMNDEF **recinfo, + ulonglong options); +bool instantiate_tmp_table(TABLE *table, KEY *keyinfo, + TMP_ENGINE_COLUMNDEF *start_recinfo, + TMP_ENGINE_COLUMNDEF **recinfo, + ulonglong options); +bool open_tmp_table(TABLE *table); +double prev_record_reads(const POSITION *positions, uint idx, table_map found_ref); +void fix_list_after_tbl_changes(SELECT_LEX *new_parent, List<TABLE_LIST> *tlist); +double get_tmp_table_lookup_cost(THD *thd, double row_count, uint row_size); +double get_tmp_table_write_cost(THD *thd, double row_count, uint row_size); +void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array); +bool sort_and_filter_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse, + bool skip_unprefixed_keyparts); + +struct st_cond_statistic +{ + Item *cond; + Field *field_arg; + ulong positive; +}; +typedef struct st_cond_statistic COND_STATISTIC; + +ulong check_selectivity(THD *thd, + ulong rows_to_read, + TABLE *table, + List<COND_STATISTIC> *conds); + +class Pushdown_query: public Sql_alloc +{ +public: + SELECT_LEX *select_lex; + bool store_data_in_temp_table; + group_by_handler *handler; + Item *having; + + Pushdown_query(SELECT_LEX *select_lex_arg, group_by_handler *handler_arg) + : select_lex(select_lex_arg), store_data_in_temp_table(0), + handler(handler_arg), having(0) {} + + ~Pushdown_query() { delete handler; } + + /* Function that calls the above scan functions */ + int execute(JOIN *); +}; + +class derived_handler; + +class Pushdown_derived: public Sql_alloc +{ +public: + TABLE_LIST *derived; + derived_handler *handler; + + Pushdown_derived(TABLE_LIST *tbl, derived_handler *h); + + int execute(); +}; + + +class select_handler; + + +bool test_if_order_compatible(SQL_I_List<ORDER> &a, SQL_I_List<ORDER> &b); +int test_if_group_changed(List<Cached_item> &list); +int create_sort_index(THD *thd, JOIN *join, JOIN_TAB *tab, Filesort *fsort); + +JOIN_TAB *first_explain_order_tab(JOIN* join); +JOIN_TAB *next_explain_order_tab(JOIN* join, JOIN_TAB* tab); + +bool is_eliminated_table(table_map eliminated_tables, TABLE_LIST *tbl); + +bool check_simple_equality(THD *thd, const Item::Context &ctx, + Item *left_item, Item *right_item, + COND_EQUAL *cond_equal); + +void propagate_new_equalities(THD *thd, Item *cond, + List<Item_equal> *new_equalities, + COND_EQUAL *inherited, + bool *is_simplifiable_cond); + +bool dbug_user_var_equals_str(THD *thd, const char *name, const char *value); +#endif /* SQL_SELECT_INCLUDED */ |