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https://github.com/mariadb-corporation/mariadb-columnstore-engine.git
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53b9a2a0f9
The idea is relatively simple - encode prefixes of collated strings as integers and use them to compute extents' ranges. Then we can eliminate extents with strings. The actual patch does have all the code there but miss one important step: we do not keep collation index, we keep charset index. Because of this, some of the tests in the bugfix suite fail and thus main functionality is turned off. The reason of this patch to be put into PR at all is that it contains changes that made CHAR/VARCHAR columns unsigned. This change is needed in vectorization work.
33 lines
1.3 KiB
C
33 lines
1.3 KiB
C
/*
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Copyright (C) 2021, 2022 MariaDB Corporation
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; version 2 of
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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 Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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/* handling of the conversion of string prefixes to int64_t for quick range checking */
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#pragma once
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#include <stdlib.h>
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#include <stdint.h>
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// Encode string prefix into an int64_t, packing as many chars from string as possible
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// into the result and respecting the collation provided by charsetNumber.
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//
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// For one example, for CI Czech collation, encodeStringPrefix("cz") < encodeStringPrefix("CH").
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int64_t encodeStringPrefix(const uint8_t* str, size_t len, int charsetNumber);
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int64_t encodeStringPrefix_check_null(const uint8_t* str, size_t len, int charsetNumber);
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