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51 lines
1.8 KiB
51 lines
1.8 KiB
5 months ago
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#ifndef OPT_STATISTICS_INCLUDED
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#define OPT_STATISTICS_INCLUDED
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/*
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Copyright (c) 2014, 2017, 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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#include <sys/types.h>
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#include "my_inttypes.h" // IWYU pragma: keep
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struct TABLE;
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typedef float rec_per_key_t;
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class KEY;
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/**
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Guesstimate for "records per key" when index statistics is not available.
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@param table the table
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@param key the index
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@param used_keyparts the number of key part that should be included in the
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estimate
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@return estimated records per key value
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*/
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rec_per_key_t guess_rec_per_key(const TABLE *const table, const KEY *const key,
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uint used_keyparts);
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#endif /* OPT_STATISTICS_INCLUDED */
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