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- Committer: Brian Aker
- Date: 2009-05-29 23:52:19 UTC
- mfrom: (1039.2.1 working)
- Revision ID: brian@gaz-20090529235219-f9hodej510x4bwyj
Merge Jay
- files added:
- drizzled/join.h
- files modified:
- drizzled/Makefile.am
added
removed
drizzled/join.h
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/* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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*
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* Copyright (C) 2008-2009 Sun Microsystems
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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*
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* Defines the JOIN class
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*/
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#ifndef DRIZZLED_JOIN_H
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#define DRIZZLED_JOIN_H
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class JOIN :public Sql_alloc
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{
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JOIN(const JOIN &rhs); /**< not implemented */
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JOIN& operator=(const JOIN &rhs); /**< not implemented */
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public:
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JOIN_TAB *join_tab;
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JOIN_TAB **best_ref;
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JOIN_TAB **map2table; /**< mapping between table indexes and JOIN_TABs */
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JOIN_TAB *join_tab_save; /**< saved join_tab for subquery reexecution */
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Table **table;
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Table **all_tables;
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/**
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The table which has an index that allows to produce the requried ordering.
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A special value of 0x1 means that the ordering will be produced by
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passing 1st non-const table to filesort(). NULL means no such table exists.
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*/
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Table *sort_by_table;
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uint32_t tables; /**< Number of tables in the join */
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uint32_t outer_tables; /**< Number of tables that are not inside semijoin */
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uint32_t const_tables;
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uint32_t send_group_parts;
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bool sort_and_group;
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bool first_record;
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bool full_join;
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bool group;
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bool no_field_update;
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bool do_send_rows;
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/**
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true when we want to resume nested loop iterations when
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fetching data from a cursor
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*/
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bool resume_nested_loop;
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/**
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true <=> optimizer must not mark any table as a constant table.
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This is needed for subqueries in form "a IN (SELECT .. UNION SELECT ..):
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when we optimize the select that reads the results of the union from a
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temporary table, we must not mark the temp. table as constant because
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the number of rows in it may vary from one subquery execution to another.
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*/
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bool no_const_tables;
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bool select_distinct; /**< Set if SELECT DISTINCT */
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/**
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If we have the GROUP BY statement in the query,
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but the group_list was emptied by optimizer, this
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flag is true.
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It happens when fields in the GROUP BY are from
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constant table
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*/
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bool group_optimized_away;
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/*
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simple_xxxxx is set if order_st/GROUP BY doesn't include any references
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to other tables than the first non-constant table in the JOIN.
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It's also set if order_st/GROUP BY is empty.
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*/
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bool simple_order;
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bool simple_group;
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/**
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Is set only in case if we have a GROUP BY clause
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and no order_st BY after constant elimination of 'order'.
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*/
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bool no_order;
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/** Is set if we have a GROUP BY and we have order_st BY on a constant. */
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bool skip_sort_order;
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bool union_part; /**< this subselect is part of union */
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bool optimized; /**< flag to avoid double optimization in EXPLAIN */
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bool need_tmp;
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bool hidden_group_fields;
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table_map const_table_map;
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table_map found_const_table_map;
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table_map outer_join;
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ha_rows send_records;
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ha_rows found_records;
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ha_rows examined_rows;
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ha_rows row_limit;
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ha_rows select_limit;
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/**
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Used to fetch no more than given amount of rows per one
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fetch operation of server side cursor.
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The value is checked in end_send and end_send_group in fashion, similar
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to offset_limit_cnt:
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- fetch_limit= HA_POS_ERROR if there is no cursor.
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- when we open a cursor, we set fetch_limit to 0,
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- on each fetch iteration we add num_rows to fetch to fetch_limit
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*/
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ha_rows fetch_limit;
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Session *session;
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List<Item> *fields;
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List<Item> &fields_list; /**< hold field list passed to mysql_select */
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List<TableList> *join_list; /**< list of joined tables in reverse order */
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/** unit structure (with global parameters) for this select */
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Select_Lex_Unit *unit;
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/** select that processed */
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Select_Lex *select_lex;
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SQL_SELECT *select; /**< created in optimisation phase */
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Array<Item_in_subselect> sj_subselects;
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POSITION positions[MAX_TABLES+1];
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POSITION best_positions[MAX_TABLES+1];
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/**
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Bitmap of nested joins embedding the position at the end of the current
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partial join (valid only during join optimizer run).
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*/
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nested_join_map cur_embedding_map;
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double best_read;
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List<Cached_item> group_fields;
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List<Cached_item> group_fields_cache;
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Table *tmp_table;
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/** used to store 2 possible tmp table of SELECT */
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Table *exec_tmp_table1;
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Table *exec_tmp_table2;
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Item_sum **sum_funcs;
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Item_sum ***sum_funcs_end;
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/** second copy of sumfuncs (for queries with 2 temporary tables */
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Item_sum **sum_funcs2;
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Item_sum ***sum_funcs_end2;
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Item *having;
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Item *tmp_having; /**< To store having when processed temporary table */
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Item *having_history; /**< Store having for explain */
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uint64_t select_options;
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select_result *result;
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Tmp_Table_Param tmp_table_param;
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DRIZZLE_LOCK *lock;
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JOIN *tmp_join; /**< copy of this JOIN to be used with temporary tables */
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ROLLUP rollup; /**< Used with rollup */
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DYNAMIC_ARRAY keyuse;
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Item::cond_result cond_value;
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Item::cond_result having_value;
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List<Item> all_fields; /**< to store all fields that used in query */
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/** Above list changed to use temporary table */
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List<Item> tmp_all_fields1;
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List<Item> tmp_all_fields2;
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List<Item> tmp_all_fields3;
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/** Part, shared with list above, emulate following list */
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List<Item> tmp_fields_list1;
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List<Item> tmp_fields_list2;
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List<Item> tmp_fields_list3;
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int error;
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order_st *order;
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order_st *group_list; /**< hold parameters of mysql_select */
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COND *conds; // ---"---
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Item *conds_history; /**< store WHERE for explain */
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TableList *tables_list; /**< hold 'tables' parameter of mysql_select */
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COND_EQUAL *cond_equal;
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JOIN_TAB *return_tab; /**< used only for outer joins */
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Item **ref_pointer_array; /**< used pointer reference for this select */
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/** Copy of above to be used with different lists */
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Item **items0;
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Item **items1;
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Item **items2;
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Item **items3;
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Item **current_ref_pointer_array;
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uint32_t ref_pointer_array_size; ///< size of above in bytes
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const char *zero_result_cause; ///< not 0 if exec must return zero result
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/* Descriptions of temporary tables used to weed-out semi-join duplicates */
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SJ_TMP_TABLE *sj_tmp_tables;
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table_map cur_emb_sj_nests;
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/*
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storage for caching buffers allocated during query execution.
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These buffers allocations need to be cached as the thread memory pool is
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cleared only at the end of the execution of the whole query and not caching
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allocations that occur in repetition at execution time will result in
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excessive memory usage.
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*/
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SORT_FIELD *sortorder; // make_unireg_sortorder()
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Table **table_reexec; // make_simple_join()
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JOIN_TAB *join_tab_reexec; // make_simple_join()
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/* end of allocation caching storage */
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/** Constructors */
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JOIN(Session *session_arg,
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List<Item> &fields_arg,
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uint64_t select_options_arg,
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select_result *result_arg)
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:
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join_tab(NULL),
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best_ref(NULL),
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map2table(NULL),
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join_tab_save(NULL),
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table(NULL),
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all_tables(NULL),
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sort_by_table(NULL),
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tables(0),
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outer_tables(0),
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const_tables(0),
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send_group_parts(0),
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sort_and_group(false),
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first_record(false),
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full_join(false),
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group(false),
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no_field_update(false),
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do_send_rows(true),
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resume_nested_loop(false),
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no_const_tables(false),
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select_distinct(false),
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group_optimized_away(false),
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simple_order(false),
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simple_group(false),
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no_order(false),
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skip_sort_order(false),
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union_part(false),
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optimized(false),
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need_tmp(false),
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hidden_group_fields(false),
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const_table_map(NULL),
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found_const_table_map(NULL),
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outer_join(NULL),
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send_records(0),
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found_records(0),
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examined_rows(0),
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row_limit(0),
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select_limit(0),
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fetch_limit(HA_POS_ERROR),
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session(session_arg),
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fields_list(fields_arg),
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join_list(NULL),
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unit(NULL),
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select_lex(NULL),
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select(NULL),
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sj_subselects(session_arg->mem_root, 4),
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exec_tmp_table1(NULL),
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exec_tmp_table2(NULL),
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sum_funcs(NULL),
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sum_funcs2(NULL),
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having(NULL),
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tmp_having(NULL),
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having_history(NULL),
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select_options(select_options_arg),
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result(result_arg),
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lock(session_arg->lock),
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tmp_join(NULL),
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all_fields(fields_arg),
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error(0),
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cond_equal(NULL),
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return_tab(NULL),
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ref_pointer_array(NULL),
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items0(NULL),
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items1(NULL),
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items2(NULL),
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items3(NULL),
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ref_pointer_array_size(0),
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zero_result_cause(NULL),
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sj_tmp_tables(NULL),
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sortorder(NULL),
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table_reexec(NULL),
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join_tab_reexec(NULL)
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{
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select_distinct= test(select_options & SELECT_DISTINCT);
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if (&fields_list != &fields_arg) /* only copy if not same*/
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fields_list= fields_arg;
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memset(&keyuse, 0, sizeof(keyuse));
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tmp_table_param.init();
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tmp_table_param.end_write_records= HA_POS_ERROR;
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rollup.state= ROLLUP::STATE_NONE;
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}
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/**
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* This method is currently only used when a subselect EXPLAIN is performed.
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* I pulled out the init() method and have simply reset the values to what
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* was previously in the init() method. See the note about the hack in
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* sql_union.cc...
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*/
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inline void reset(Session *session_arg,
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List<Item> &fields_arg,
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uint64_t select_options_arg,
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select_result *result_arg)
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{
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join_tab= NULL;
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best_ref= NULL;
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map2table= NULL;
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join_tab_save= NULL;
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table= NULL;
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all_tables= NULL;
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sort_by_table= NULL;
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tables= 0;
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outer_tables= 0;
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const_tables= 0;
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send_group_parts= 0;
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sort_and_group= false;
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first_record= false;
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full_join= false;
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group= false;
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no_field_update= false;
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do_send_rows= true;
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resume_nested_loop= false;
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no_const_tables= false;
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select_distinct= false;
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group_optimized_away= false;
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simple_order= false;
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simple_group= false;
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no_order= false;
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skip_sort_order= false;
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union_part= false;
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optimized= false;
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need_tmp= false;
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hidden_group_fields= false;
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const_table_map= NULL;
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found_const_table_map= NULL;
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outer_join= NULL;
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send_records= 0;
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found_records= 0;
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examined_rows= 0;
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row_limit= 0;
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select_limit= 0;
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fetch_limit= HA_POS_ERROR;
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session= session_arg;
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fields_list= fields_arg;
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join_list= NULL;
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unit= NULL;
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select_lex= NULL;
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select= NULL;
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exec_tmp_table1= NULL;
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exec_tmp_table2= NULL;
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sum_funcs= NULL;
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sum_funcs2= NULL;
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having= NULL;
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tmp_having= NULL;
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having_history= NULL;
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select_options= select_options_arg;
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result= result_arg;
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lock= session_arg->lock;
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tmp_join= NULL;
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all_fields= fields_arg;
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error= 0;
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cond_equal= NULL;
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return_tab= NULL;
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ref_pointer_array= NULL;
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items0= NULL;
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items1= NULL;
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items2= NULL;
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items3= NULL;
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ref_pointer_array_size= 0;
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zero_result_cause= NULL;
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sj_tmp_tables= NULL;
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sortorder= NULL;
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table_reexec= NULL;
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join_tab_reexec= NULL;
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select_distinct= test(select_options & SELECT_DISTINCT);
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if (&fields_list != &fields_arg) /* only copy if not same*/
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fields_list= fields_arg;
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memset(&keyuse, 0, sizeof(keyuse));
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tmp_table_param.init();
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tmp_table_param.end_write_records= HA_POS_ERROR;
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rollup.state= ROLLUP::STATE_NONE;
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}
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int prepare(Item ***rref_pointer_array,
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TableList *tables,
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uint32_t wind_num,
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COND *conds,
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uint32_t og_num,
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order_st *order,
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order_st *group,
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Item *having,
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Select_Lex *select,
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Select_Lex_Unit *unit);
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int optimize();
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int reinit();
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void exec();
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int destroy();
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void restore_tmp();
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bool alloc_func_list();
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bool flatten_subqueries();
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bool setup_subquery_materialization();
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bool make_sum_func_list(List<Item> &all_fields,
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List<Item> &send_fields,
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bool before_group_by,
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bool recompute= false);
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inline void set_items_ref_array(Item **ptr)
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{
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memcpy(ref_pointer_array, ptr, ref_pointer_array_size);
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current_ref_pointer_array= ptr;
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}
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inline void init_items_ref_array()
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{
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items0= ref_pointer_array + all_fields.elements;
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memcpy(items0, ref_pointer_array, ref_pointer_array_size);
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current_ref_pointer_array= items0;
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}
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bool rollup_init();
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bool rollup_make_fields(List<Item> &all_fields,
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List<Item> &fields,
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Item_sum ***func);
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int rollup_send_data(uint32_t idx);
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int rollup_write_data(uint32_t idx, Table *table);
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void remove_subq_pushed_predicates(Item **where);
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/**
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Release memory and, if possible, the open tables held by this execution
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plan (and nested plans). It's used to release some tables before
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the end of execution in order to increase concurrency and reduce
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memory consumption.
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*/
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void join_free();
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/** Cleanup this JOIN, possibly for reuse */
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void cleanup(bool full);
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void clear();
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bool save_join_tab();
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bool init_save_join_tab();
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bool send_row_on_empty_set()
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{
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return (do_send_rows && tmp_table_param.sum_func_count != 0 &&
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!group_list);
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}
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bool change_result(select_result *result);
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bool is_top_level_join() const
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{
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return (unit == &session->lex->unit && (unit->fake_select_lex == 0 ||
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select_lex == unit->fake_select_lex));
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}
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};
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#endif /* DRIZZLED_JOIN_H */
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