includes/libs/rdbms/database/utils/GeneralizedSql.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  * @ingroup Profiler
  20  */
  21
  22 namespace Wikimedia\Rdbms;
  23
  24 /**
  25  * Lazy-loaded wrapper for simplification and scrubbing of SQL queries for profiling
  26  *
  27  * @since 1.34
  28  */
  29 class GeneralizedSql {
  30         /** @var string */
  31         private $rawSql;
  32         /** @var string */
  33         private $trxId;
  34         /** @var string */
  35         private $prefix;
  36
  37         /** @var string|null */
  38         private $genericSql;
  39
  40         /**
  41          * @param string $rawSql
  42          * @param string $trxId
  43          * @param string $prefix
  44          */
  45         public function __construct( $rawSql, $trxId, $prefix ) {
  46                 $this->rawSql = $rawSql;
  47                 $this->trxId = $trxId;
  48                 $this->prefix = $prefix;
  49         }
  50
  51         /**
  52          * Removes most variables from an SQL query and replaces them with X or N for numbers.
  53          * It's only slightly flawed. Don't use for anything important.
  54          *
  55          * @param string $sql A SQL Query
  56          *
  57          * @return string
  58          */
  59         private static function generalizeSQL( $sql ) {
  60                 # This does the same as the regexp below would do, but in such a way
  61                 # as to avoid crashing php on some large strings.
  62                 # $sql = preg_replace( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql );
  63
  64                 $sql = str_replace( "\\\\", '', $sql );
  65                 $sql = str_replace( "\\'", '', $sql );
  66                 $sql = str_replace( "\\\"", '', $sql );
  67                 $sql = preg_replace( "/'.*'/s", "'X'", $sql );
  68                 $sql = preg_replace( '/".*"/s', "'X'", $sql );
  69
  70                 # All newlines, tabs, etc replaced by single space
  71                 $sql = preg_replace( '/\s+/', ' ', $sql );
  72
  73                 # All numbers => N,
  74                 # except the ones surrounded by characters, e.g. l10n
  75                 $sql = preg_replace( '/-?\d+(,-?\d+)+/s', 'N,...,N', $sql );
  76                 $sql = preg_replace( '/(?<![a-zA-Z])-?\d+(?![a-zA-Z])/s', 'N', $sql );
  77
  78                 return $sql;
  79         }
  80
  81         /**
  82          * @return string
  83          */
  84         public function stringify() {
  85                 if ( $this->genericSql !== null ) {
  86                         return $this->genericSql;
  87                 }
  88
  89                 $this->genericSql = $this->prefix .
  90                         substr( self::generalizeSQL( $this->rawSql ), 0, 255 ) .
  91                         ( $this->trxId ? " [TRX#{$this->trxId}]" : "" );
  92
  93                 return $this->genericSql;
  94         }
  95 }