maintenance/fixSlaveDesync.php

   1 <?php
   2 /**
   3  * Fix erroneous page_latest values due to slave desynchronisation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @ingroup Maintenance
  21  */
  22
  23 require_once( dirname( __FILE__ ) . '/Maintenance.php' );
  24
  25 /**
  26  * Maintenance script that fixes erroneous page_latest values
  27  * due to slave desynchronisation.
  28  *
  29  * @ingroup Maintenance
  30  */
  31 class FixSlaveDesync extends Maintenance {
  32         public function __construct() {
  33                 parent::__construct();
  34                 $this->mDescription = "";
  35         }
  36
  37         public function getDbType() {
  38                 return Maintenance::DB_ADMIN;
  39         }
  40
  41         public function execute() {
  42                 $this->slaveIndexes = array();
  43                 for ( $i = 1; $i < wfGetLB()->getServerCount(); $i++ ) {
  44                         if ( wfGetLB()->isNonZeroLoad( $i ) ) {
  45                                 $this->slaveIndexes[] = $i;
  46                         }
  47                 }
  48
  49                 if ( $this->hasArg() ) {
  50                         $this->desyncFixPage( $this->getArg() );
  51                 } else {
  52                         $corrupt = $this->findPageLatestCorruption();
  53                         foreach ( $corrupt as $id => $dummy ) {
  54                                 $this->desyncFixPage( $id );
  55                         }
  56                 }
  57         }
  58
  59         /**
  60          * Find all pages that have a corrupted page_latest
  61          * @return array
  62          */
  63         private function findPageLatestCorruption() {
  64                 $desync = array();
  65                 $n = 0;
  66                 $dbw = wfGetDB( DB_MASTER );
  67                 $masterIDs = array();
  68                 $res = $dbw->select( 'page', array( 'page_id', 'page_latest' ), array( 'page_id<6054123' ), __METHOD__ );
  69                 $this->output( "Number of pages: " . $dbw->numRows( $res ) . "\n" );
  70                 foreach ( $res as $row ) {
  71                         $masterIDs[$row->page_id] = $row->page_latest;
  72                         if ( !( ++$n % 10000 ) ) {
  73                                 $this->output( "$n\r" );
  74                         }
  75                 }
  76                 $this->output( "\n" );
  77
  78                 foreach ( $this->slaveIndexes as $i ) {
  79                         $db = wfGetDB( $i );
  80                         $res = $db->select( 'page', array( 'page_id', 'page_latest' ), array( 'page_id<6054123' ), __METHOD__ );
  81                         foreach ( $res as $row ) {
  82                                 if ( isset( $masterIDs[$row->page_id] ) && $masterIDs[$row->page_id] != $row->page_latest ) {
  83                                         $desync[$row->page_id] = true;
  84                                         $this->output( $row->page_id . "\t" );
  85                                 }
  86                         }
  87                 }
  88                 $this->output( "\n" );
  89                 return $desync;
  90         }
  91
  92         /**
  93          * Fix a broken page entry
  94          * @param $pageID int The page_id to fix
  95          */
  96         private function desyncFixPage( $pageID ) {
  97                 # Check for a corrupted page_latest
  98                 $dbw = wfGetDB( DB_MASTER );
  99                 $dbw->begin( __METHOD__ );
 100                 $realLatest = $dbw->selectField( 'page', 'page_latest', array( 'page_id' => $pageID ),
 101                         __METHOD__, 'FOR UPDATE' );
 102                 # list( $masterFile, $masterPos ) = $dbw->getMasterPos();
 103                 $found = false;
 104                 foreach ( $this->slaveIndexes as $i ) {
 105                         $db = wfGetDB( $i );
 106                         /*
 107                         if ( !$db->masterPosWait( $masterFile, $masterPos, 10 ) ) {
 108                                    $this->output( "Slave is too lagged, aborting\n" );
 109                                    $dbw->commit( __METHOD__ );
 110                                    sleep(10);
 111                                    return;
 112                         }*/
 113                         $latest = $db->selectField( 'page', 'page_latest', array( 'page_id' => $pageID ), __METHOD__ );
 114                         $max = $db->selectField( 'revision', 'MAX(rev_id)', false, __METHOD__ );
 115                         if ( $latest != $realLatest && $realLatest < $max ) {
 116                                 $this->output( "page_latest corrupted in page $pageID, server $i\n" );
 117                                 $found = true;
 118                                 break;
 119                         }
 120                 }
 121                 if ( !$found ) {
 122                         $this->output( "page_id $pageID seems fine\n" );
 123                         $dbw->commit( __METHOD__ );
 124                         return;
 125                 }
 126
 127                 # Find the missing revisions
 128                 $res = $dbw->select( 'revision', array( 'rev_id' ), array( 'rev_page' => $pageID ),
 129                         __METHOD__, 'FOR UPDATE' );
 130                 $masterIDs = array();
 131                 foreach ( $res as $row ) {
 132                         $masterIDs[] = $row->rev_id;
 133                 }
 134
 135                 $res = $dbw->select( 'revision', array( 'rev_id' ), array( 'rev_page' => $pageID ), __METHOD__ );
 136                 $slaveIDs = array();
 137                 foreach ( $res as $row ) {
 138                         $slaveIDs[] = $row->rev_id;
 139                 }
 140                 if ( count( $masterIDs ) < count( $slaveIDs ) ) {
 141                         $missingIDs = array_diff( $slaveIDs, $masterIDs );
 142                         if ( count( $missingIDs ) ) {
 143                                 $this->output( "Found " . count( $missingIDs ) . " lost in master, copying from slave... " );
 144                                 $dbFrom = $dbw;
 145                                 $found = true;
 146                                 $toMaster = true;
 147                         } else {
 148                                 $found = false;
 149                         }
 150                 } else {
 151                         $missingIDs = array_diff( $masterIDs, $slaveIDs );
 152                         if ( count( $missingIDs ) ) {
 153                                 $this->output( "Found " . count( $missingIDs ) . " missing revision(s), copying from master... " );
 154                                 $dbFrom = $dbw;
 155                                 $found = true;
 156                                 $toMaster = false;
 157                         } else {
 158                                 $found = false;
 159                         }
 160                 }
 161
 162                 if ( $found ) {
 163                         foreach ( $missingIDs as $rid ) {
 164                                 $this->output( "$rid " );
 165                                 # Revision
 166                                 $row = $dbFrom->selectRow( 'revision', '*', array( 'rev_id' => $rid ), __METHOD__ );
 167                                 if ( $toMaster ) {
 168                                         $id = $dbw->selectField( 'revision', 'rev_id', array( 'rev_id' => $rid ),
 169                                                 __METHOD__, 'FOR UPDATE' );
 170                                         if ( $id ) {
 171                                                 $this->output( "Revision already exists\n" );
 172                                                 $found = false;
 173                                                 break;
 174                                         } else {
 175                                                 $dbw->insert( 'revision', get_object_vars( $row ), __METHOD__, 'IGNORE' );
 176                                         }
 177                                 } else {
 178                                         foreach ( $this->slaveIndexes as $i ) {
 179                                                 $db = wfGetDB( $i );
 180                                                 $db->insert( 'revision', get_object_vars( $row ), __METHOD__, 'IGNORE' );
 181                                         }
 182                                 }
 183
 184                                 # Text
 185                                 $row = $dbFrom->selectRow( 'text', '*', array( 'old_id' => $row->rev_text_id ), __METHOD__ );
 186                                 if ( $toMaster ) {
 187                                         $dbw->insert( 'text', get_object_vars( $row ), __METHOD__, 'IGNORE' );
 188                                 } else {
 189                                         foreach ( $this->slaveIndexes as $i ) {
 190                                                 $db = wfGetDB( $i );
 191                                                 $db->insert( 'text', get_object_vars( $row ), __METHOD__, 'IGNORE' );
 192                                         }
 193                                 }
 194                         }
 195                         $this->output( "done\n" );
 196                 }
 197
 198                 if ( $found ) {
 199                         $this->output( "Fixing page_latest... " );
 200                         if ( $toMaster ) {
 201                                 # $dbw->update( 'page', array( 'page_latest' => $realLatest ), array( 'page_id' => $pageID ), __METHOD__ );
 202                         } else {
 203                                 foreach ( $this->slaveIndexes as $i ) {
 204                                         $db = wfGetDB( $i );
 205                                         $db->update( 'page', array( 'page_latest' => $realLatest ), array( 'page_id' => $pageID ), __METHOD__ );
 206                                 }
 207                         }
 208                         $this->output( "done\n" );
 209                 }
 210                 $dbw->commit( __METHOD__ );
 211         }
 212 }
 213
 214 $maintClass = "FixSlaveDesync";
 215 require_once( RUN_MAINTENANCE_IF_MAIN );