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                 $ttr = 5; // try to refresh before this many seconds
  30                 $age = microtime( true ) - $status['asOfTime']; // seconds
  31                 $chance = min( 1, $age / $ttr );
  32
  33                 $scopedLock = ( mt_rand( 1, 1e9 ) <= 1e9 * $chance )
  34                         ? $bcache->getScopedLock( $virtualKey )
  35                         : false;
  36
  37                 if ( $scopedLock ) {
  38                         $updates = self::merge( $bcache, $domain, $virtualKey, $status );
  39                         if ( isset( $updates['asOfTime'] ) ) {
  40                                 $age = ( microtime( true ) - $updates['asOfTime'] );
  41                         }
  42                 }
  43
  44                 return ( $age < 30 );
  45         }
  46
  47         public static function merge(
  48                 BloomCache $bcache, $domain, $virtualKey, array $status
  49         ) {
  50                 $limit = 1000;
  51                 $dbr = wfGetDB( DB_SLAVE, array(), $domain );
  52                 $res = $dbr->select( 'logging',
  53                         array( 'log_namespace', 'log_title', 'log_id', 'log_timestamp' ),
  54                         array( 'log_id > ' . $dbr->addQuotes( (int)$status['lastID'] ) ),
  55                         __METHOD__,
  56                         array( 'ORDER BY' => 'log_id', 'LIMIT' => $limit )
  57                 );
  58
  59                 $updates = array();
  60                 if ( $res->numRows() > 0 ) {
  61                         $members = array();
  62                         foreach ( $res as $row ) {
  63                                 $members[] = "$virtualKey:{$row->log_namespace}:{$row->log_title}";
  64                         }
  65                         $lastID = $row->log_id;
  66                         $lastTime = $row->log_timestamp;
  67                         if ( !$bcache->add( 'shared', $members ) ) {
  68                                 return false;
  69                         }
  70                         $updates['lastID'] = $lastID;
  71                         $updates['asOfTime'] = wfTimestamp( TS_UNIX, $lastTime );
  72                 } else {
  73                         $updates['asOfTime'] = microtime( true );
  74                 }
  75
  76                 $updates['epoch'] = $status['epoch'] ?: microtime( true );
  77
  78                 $bcache->setStatus( $virtualKey, $updates );
  79
  80                 return $updates;
  81         }
  82 }