includes/cache/bloom/BloomFilters.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  * @author Aaron Schulz
  20  */
  21
  22 /**
  23  * @since 1.24
  24  */
  25 class BloomFilterTitleHasLogs {
  26         public static function mergeAndCheck(
  27                 BloomCache $bcache, $domain, $virtualKey, array $status
  28         ) {
  29                 $age = microtime( true ) - $status['asOfTime']; // seconds
  30                 $scopedLock = ( mt_rand( 1, (int)pow( 3, max( 0, 5 - $age ) ) ) == 1 )
  31                         ? $bcache->getScopedLock( $virtualKey )
  32                         : false;
  33
  34                 if ( $scopedLock ) {
  35                         $updates = self::merge( $bcache, $domain, $virtualKey, $status );
  36                         if ( isset( $updates['asOfTime'] ) ) {
  37                                 $age = ( microtime( true ) - $updates['asOfTime'] );
  38                         }
  39                 }
  40
  41                 return ( $age < 30 );
  42         }
  43
  44         public static function merge(
  45                 BloomCache $bcache, $domain, $virtualKey, array $status
  46         ) {
  47                 $limit = 1000;
  48                 $dbr = wfGetDB( DB_SLAVE, array(), $domain );
  49                 $res = $dbr->select( 'logging',
  50                         array( 'log_namespace', 'log_title', 'log_id', 'log_timestamp' ),
  51                         array( 'log_id > ' . $dbr->addQuotes( (int)$status['lastID'] ) ),
  52                         __METHOD__,
  53                         array( 'ORDER BY' => 'log_id', 'LIMIT' => $limit )
  54                 );
  55
  56                 $updates = array();
  57                 if ( $res->numRows() > 0 ) {
  58                         $members = array();
  59                         foreach ( $res as $row ) {
  60                                 $members[] = "$virtualKey:{$row->log_namespace}:{$row->log_title}";
  61                         }
  62                         $lastID = $row->log_id;
  63                         $lastTime = $row->log_timestamp;
  64                         if ( !$bcache->add( 'shared', $members ) ) {
  65                                 return false;
  66                         }
  67                         $updates['lastID'] = $lastID;
  68                         $updates['asOfTime'] = wfTimestamp( TS_UNIX, $lastTime );
  69                 } else {
  70                         $updates['asOfTime'] = microtime( true );
  71                 }
  72
  73                 $updates['epoch'] = $status['epoch'] ?: microtime( true );
  74
  75                 $bcache->setStatus( $virtualKey, $updates );
  76
  77                 return $updates;
  78         }
  79 }