mirror of
https://github.com/mariadb-corporation/mariadb-columnstore-engine.git
synced 2025-04-23 07:05:36 +03:00
b53c231ca6
This patch improves handling of NULLs in textual fields in ColumnStore. Previously empty strings were considered NULLs and it could be a problem if data scheme allows for empty strings. It was also one of major reasons of behavior difference between ColumnStore and other engines in MariaDB family. Also, this patch fixes some other bugs and incorrect behavior, for example, incorrect comparison for "column <= ''" which evaluates to constant True for all purposes before this patch.
94 lines
2.8 KiB
C++
94 lines
2.8 KiB
C++
/* Copyright (C) 2014 InfiniDB, Inc.
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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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/****************************************************************************
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* $Id: func_ltrim.cpp 3923 2013-06-19 21:43:06Z bwilkinson $
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*
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*
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****************************************************************************/
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#include <string>
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using namespace std;
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#include "functor_str.h"
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#include "functioncolumn.h"
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using namespace execplan;
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#include "rowgroup.h"
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using namespace rowgroup;
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#include "joblisttypes.h"
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using namespace joblist;
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namespace funcexp
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{
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CalpontSystemCatalog::ColType Func_ltrim::operationType(FunctionParm& fp,
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CalpontSystemCatalog::ColType& resultType)
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{
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// operation type is not used by this functor
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return fp[0]->data()->resultType();
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}
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std::string Func_ltrim::getStrVal(rowgroup::Row& row, FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& type)
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{
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CHARSET_INFO* cs = type.getCharset();
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// The original string
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const auto& src = fp[0]->data()->getStrVal(row, isNull);
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if (isNull || src.length() < 1)
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return "";
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// binLen represents the number of bytes in src
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size_t binLen = src.length();
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const char* pos = src.str();
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const char* end = pos + binLen;
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// strLen = the number of characters in src
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size_t strLen = cs->numchars(pos, end);
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// The trim characters.
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const string& trim = (fp.size() > 1 ? fp[1]->data()->getStrVal(row, isNull).safeString("") : " ");
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// binTLen represents the number of bytes in trim
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size_t binTLen = trim.length();
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const char* posT = trim.c_str();
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// strTLen = the number of characters in trim
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size_t strTLen = cs->numchars(posT, posT + binTLen);
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if (strTLen == 0 || strTLen > strLen)
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return src.unsafeStringRef();
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if (binTLen == 1)
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{
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// If the trim string is 1 byte, don't waste cpu for memcmp
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while (pos < end && *pos == *posT)
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{
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++pos;
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--binLen;
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}
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}
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else
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{
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while (pos + binTLen <= end && memcmp(pos, posT, binTLen) == 0)
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{
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pos += binTLen;
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binLen -= binTLen;
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}
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}
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// Turn back to a string
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std::string ret(pos, binLen);
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return ret;
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}
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} // namespace funcexp
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