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226 lines
7.3 KiB
226 lines
7.3 KiB
5 months ago
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/* Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
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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, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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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, version 2.0, 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 TEMP_TABLE_PARAM_INCLUDED
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#define TEMP_TABLE_PARAM_INCLUDED
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#include <vector>
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#include "my_base.h"
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#include "sql/mem_root_array.h"
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#include "sql/sql_list.h"
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#include "sql/thr_malloc.h"
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#include "sql/window.h"
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class KEY;
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class Copy_field;
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class Item;
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class Window;
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template <typename T>
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using Memroot_vector = std::vector<T, Memroot_allocator<T>>;
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/**
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Helper class for copy_funcs(); represents an Item to copy from table to
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next tmp table.
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*/
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class Func_ptr {
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public:
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explicit Func_ptr(Item *f) : m_func(f) {}
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Item *func() const { return m_func; }
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void set_override_result_field(Field *f) { m_override_result_field = f; }
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Field *override_result_field() const { return m_override_result_field; }
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private:
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Item *m_func;
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/// If not nullptr, copy_funcs() will save the result of m_func here instead
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/// of in m_func's usual designated result field.
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Field *m_override_result_field = nullptr;
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};
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/// Used by copy_funcs()
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typedef Mem_root_array<Func_ptr> Func_ptr_array;
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/**
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Object containing parameters used when creating and using temporary
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tables. Temporary tables created with the help of this object are
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used only internally by the query execution engine.
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*/
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class Temp_table_param {
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public:
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/**
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Used to store the values of grouped non-column-reference expressions in
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between groups, so they can be retreived when the group changes.
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@see setup_copy_fields
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@see copy_fields
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*/
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Memroot_vector<Item_copy *> grouped_expressions;
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Memroot_vector<Copy_field> copy_fields;
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uchar *group_buff;
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Func_ptr_array *items_to_copy; /* Fields in tmp table */
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/**
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After temporary table creation, points to an index on the table
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created depending on the purpose of the table - grouping,
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duplicate elimination, etc. There is at most one such index.
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*/
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KEY *keyinfo;
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/**
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LIMIT (maximum number of rows) for this temp table, or HA_POS_ERROR
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for no limit. Enforced by MaterializeIterator when writing to the table.
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*/
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ha_rows end_write_records{HA_POS_ERROR};
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/**
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Number of normal fields in the query, including those referred to
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from aggregate functions. Hence, "SELECT `field1`,
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SUM(`field2`) from t1" sets this counter to 2.
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@see count_field_types
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*/
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uint field_count;
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/**
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Number of fields in the query that have functions. Includes both
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aggregate functions (e.g., SUM) and non-aggregates (e.g., RAND)
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and windowing functions.
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Also counts functions referred to from windowing or aggregate functions,
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i.e., "SELECT SUM(RAND())" sets this counter to 2.
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@see count_field_types
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*/
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uint func_count;
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/**
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Number of fields in the query that have aggregate functions. Note
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that the optimizer may choose to optimize away these fields by
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replacing them with constants, in which case sum_func_count will
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need to be updated.
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@see optimize_aggregated_query, count_field_types
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*/
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uint sum_func_count;
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uint hidden_field_count;
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uint group_parts, group_length, group_null_parts;
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/**
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Whether we allow running GROUP BY processing into a temporary table,
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i.e., keeping many different aggregations going at once without
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having ordered input. This is usually the case, but is currently not
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supported for aggregation UDFs, aggregates with DISTINCT, or ROLLUP.
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Note that even if this is true, the optimizer may choose to not use
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a temporary table, as it is often more efficient to just read along
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an index.
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*/
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bool allow_group_via_temp_table{true};
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/**
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Number of outer_sum_funcs i.e the number of set functions that are
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aggregated in a query block outer to this subquery.
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@see count_field_types
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*/
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uint outer_sum_func_count;
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/**
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Enabled when we have atleast one outer_sum_func. Needed when used
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along with distinct.
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@see create_tmp_table
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*/
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bool using_outer_summary_function;
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CHARSET_INFO *table_charset;
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bool schema_table;
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/*
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True if GROUP BY and its aggregate functions are already computed
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by a table access method (e.g. by loose index scan). In this case
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query execution should not perform aggregation and should treat
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aggregate functions as normal functions.
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*/
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bool precomputed_group_by;
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bool force_copy_fields;
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/**
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true <=> don't actually create table handler when creating the result
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table. This allows range optimizer to add indexes later.
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Used for materialized derived tables/views.
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@see TABLE_LIST::update_derived_keys.
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*/
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bool skip_create_table;
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/*
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If true, create_tmp_field called from create_tmp_table will convert
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all BIT fields to 64-bit longs. This is a workaround the limitation
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that MEMORY tables cannot index BIT columns.
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*/
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bool bit_fields_as_long;
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/// Whether the UNIQUE index can be promoted to PK
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bool can_use_pk_for_unique;
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/// Whether UNIQUE keys should always be implemented by way of a hidden
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/// hash field, never a unique index. Needed for materialization of mixed
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/// UNION ALL / UNION DISTINCT queries (see comments in
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/// create_result_table()).
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bool force_hash_field_for_unique{false};
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/// (Last) window's tmp file step can be skipped
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bool m_window_short_circuit;
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/// This tmp table is used for a window's frame buffer
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bool m_window_frame_buffer{false};
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/// If this is the out table of a window: the said window
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Window *m_window;
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Temp_table_param(MEM_ROOT *mem_root = *THR_MALLOC)
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: grouped_expressions(Memroot_allocator<Item_copy *>(mem_root)),
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copy_fields(Memroot_allocator<Copy_field>(mem_root)),
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group_buff(nullptr),
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items_to_copy(nullptr),
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keyinfo(NULL),
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field_count(0),
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func_count(0),
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sum_func_count(0),
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hidden_field_count(0),
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group_parts(0),
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group_length(0),
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group_null_parts(0),
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outer_sum_func_count(0),
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using_outer_summary_function(false),
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table_charset(NULL),
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schema_table(false),
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precomputed_group_by(false),
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force_copy_fields(false),
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skip_create_table(false),
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bit_fields_as_long(false),
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can_use_pk_for_unique(true),
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m_window_short_circuit(false),
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m_window(nullptr) {}
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void cleanup() {
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grouped_expressions.clear();
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copy_fields.clear();
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}
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};
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#endif // TEMP_TABLE_PARAM_INCLUDED
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