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a1fd25c22b
value constructor shows wrong number of rows If the specification of a derived table contained a table value constructor then the optimizer incorrectly estimated the number of rows in the derived table. This happened because the optimizer did not take into account the number of rows in the constructor. The wrong estimate could lead to choosing inefficient execution plans.
67 lines
2.1 KiB
Objective-C
67 lines
2.1 KiB
Objective-C
/* Copyright (c) 2017, MariaDB
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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; version 2 of the License.
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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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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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#ifndef SQL_TVC_INCLUDED
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#define SQL_TVC_INCLUDED
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#include "sql_type.h"
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typedef List<Item> List_item;
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class select_result;
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class Explain_select;
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class Explain_query;
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class Item_func_in;
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class st_select_lex_unit;
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typedef class st_select_lex SELECT_LEX;
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/**
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@class table_value_constr
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@brief Definition of a Table Value Construction(TVC)
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It contains a list of lists of values which this TVC is defined by and
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reference on SELECT where this TVC is defined.
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*/
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class table_value_constr : public Sql_alloc
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{
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public:
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List<List_item> lists_of_values;
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select_result *result;
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SELECT_LEX *select_lex;
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enum { QEP_NOT_PRESENT_YET, QEP_AVAILABLE} have_query_plan;
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Explain_select *explain;
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ulonglong select_options;
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table_value_constr(List<List_item> tvc_values, SELECT_LEX *sl,
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ulonglong select_options_arg) :
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lists_of_values(tvc_values), result(0), select_lex(sl),
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have_query_plan(QEP_NOT_PRESENT_YET), explain(0),
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select_options(select_options_arg)
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{ };
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ha_rows get_records() { return lists_of_values.elements; }
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bool prepare(THD *thd_arg, SELECT_LEX *sl,
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select_result *tmp_result,
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st_select_lex_unit *unit_arg);
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int save_explain_data_intern(THD *thd_arg,
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Explain_query *output);
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bool optimize(THD *thd_arg);
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bool exec(SELECT_LEX *sl);
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void print(THD *thd_arg, String *str, enum_query_type query_type);
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};
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#endif /* SQL_TVC_INCLUDED */
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