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  * @file
  21  * @ingroup Maintenance
  22  */
  23
  24 require_once __DIR__ . '/Maintenance.php';
  25
  26 /**
  27  * Maintenance script that fixes erroneous page_latest values
  28  * due to slave desynchronisation.
  29  *
  30  * @ingroup Maintenance
  31  */
  32 class FixSlaveDesync extends Maintenance {
  33         /** @var array */
  34         private $slaveIndexes;
  35
  36         public function __construct() {
  37                 parent::__construct();
  38                 $this->mDescription = "";
  39         }
  40
  41         public function getDbType() {
  42                 return Maintenance::DB_ADMIN;
  43         }
  44
  45         public function execute() {
  46                 $this->slaveIndexes = array();
  47                 $serverCount = wfGetLB()->getServerCount();
  48                 for ( $i = 1; $i < $serverCount; $i++ ) {
  49                         if ( wfGetLB()->isNonZeroLoad( $i ) ) {
  50                                 $this->slaveIndexes[] = $i;
  51                         }
  52                 }
  53
  54                 if ( $this->hasArg() ) {
  55                         $this->desyncFixPage( $this->getArg() );
  56                 } else {
  57                         $corrupt = $this->findPageLatestCorruption();
  58                         foreach ( $corrupt as $id => $dummy ) {
  59                                 $this->desyncFixPage( $id );
  60                         }
  61                 }
  62         }
  63
  64         /**
  65          * Find all pages that have a corrupted page_latest
  66          * @return array
  67          */
  68         private function findPageLatestCorruption() {
  69                 $desync = array();
  70                 $n = 0;
  71                 $dbw = wfGetDB( DB_MASTER );
  72                 $masterIDs = array();
  73                 $res = $dbw->select(
  74                         'page',
  75                         array( 'page_id', 'page_latest' ),
  76                         array( 'page_id<6054123' ),
  77                         __METHOD__
  78                 );
  79                 $this->output( "Number of pages: " . $res->numRows() . "\n" );
  80                 foreach ( $res as $row ) {
  81                         $masterIDs[$row->page_id] = $row->page_latest;
  82                         if ( !( ++$n % 10000 ) ) {
  83                                 $this->output( "$n\r" );
  84                         }
  85                 }
  86                 $this->output( "\n" );
  87
  88                 foreach ( $this->slaveIndexes as $i ) {
  89                         $db = wfGetDB( $i );
  90                         $res = $db->select(
  91                                 'page',
  92                                 array( 'page_id', 'page_latest' ),
  93                                 array( 'page_id<6054123' ),
  94                                 __METHOD__
  95                         );
  96                         foreach ( $res as $row ) {
  97                                 if ( isset( $masterIDs[$row->page_id] ) && $masterIDs[$row->page_id] != $row->page_latest ) {
  98                                         $desync[$row->page_id] = true;
  99                                         $this->output( $row->page_id . "\t" );
 100                                 }
 101                         }
 102                 }
 103                 $this->output( "\n" );
 104                 return $desync;
 105         }
 106
 107         /**
 108          * Fix a broken page entry
 109          * @param int $pageID The page_id to fix
 110          */
 111         private function desyncFixPage( $pageID ) {
 112                 # Check for a corrupted page_latest
 113                 $dbw = wfGetDB( DB_MASTER );
 114                 $dbw->begin( __METHOD__ );
 115                 $realLatest = $dbw->selectField( 'page', 'page_latest', array( 'page_id' => $pageID ),
 116                         __METHOD__, 'FOR UPDATE' );
 117                 # list( $masterFile, $masterPos ) = $dbw->getMasterPos();
 118                 $found = false;
 119                 foreach ( $this->slaveIndexes as $i ) {
 120                         $db = wfGetDB( $i );
 121                         /*
 122                         if ( !$db->masterPosWait( $masterFile, $masterPos, 10 ) ) {
 123                                 $this->output( "Slave is too lagged, aborting\n" );
 124                                 $dbw->commit( __METHOD__ );
 125                                 sleep(10);
 126                                 return;
 127                         }*/
 128                         $latest = $db->selectField( 'page', 'page_latest', array( 'page_id' => $pageID ), __METHOD__ );
 129                         $max = $db->selectField( 'revision', 'MAX(rev_id)', false, __METHOD__ );
 130                         if ( $latest != $realLatest && $realLatest < $max ) {
 131                                 $this->output( "page_latest corrupted in page $pageID, server $i\n" );
 132                                 $found = true;
 133                                 break;
 134                         }
 135                 }
 136                 if ( !$found ) {
 137                         $this->output( "page_id $pageID seems fine\n" );
 138                         $dbw->commit( __METHOD__ );
 139                         return;
 140                 }
 141
 142                 # Find the missing revisions
 143                 $res = $dbw->select( 'revision', array( 'rev_id' ), array( 'rev_page' => $pageID ),
 144                         __METHOD__, 'FOR UPDATE' );
 145                 $masterIDs = array();
 146                 foreach ( $res as $row ) {
 147                         $masterIDs[] = $row->rev_id;
 148                 }
 149
 150                 $res = $dbw->select( 'revision', array( 'rev_id' ), array( 'rev_page' => $pageID ), __METHOD__ );
 151                 $slaveIDs = array();
 152                 foreach ( $res as $row ) {
 153                         $slaveIDs[] = $row->rev_id;
 154                 }
 155                 if ( count( $masterIDs ) < count( $slaveIDs ) ) {
 156                         $missingIDs = array_diff( $slaveIDs, $masterIDs );
 157                         if ( count( $missingIDs ) ) {
 158                                 $this->output( "Found " . count( $missingIDs )
 159                                         . " lost in master, copying from slave... " );
 160                                 $dbFrom = $dbw;
 161                                 $found = true;
 162                                 $toMaster = true;
 163                         } else {
 164                                 $found = false;
 165                         }
 166                 } else {
 167                         $missingIDs = array_diff( $masterIDs, $slaveIDs );
 168                         if ( count( $missingIDs ) ) {
 169                                 $this->output( "Found " . count( $missingIDs )
 170                                         . " missing revision(s), copying from master... " );
 171                                 $dbFrom = $dbw;
 172                                 $found = true;
 173                                 $toMaster = false;
 174                         } else {
 175                                 $found = false;
 176                         }
 177                 }
 178
 179                 if ( $found ) {
 180                         foreach ( $missingIDs as $rid ) {
 181                                 $this->output( "$rid " );
 182                                 # Revision
 183                                 $row = $dbFrom->selectRow( 'revision', '*', array( 'rev_id' => $rid ), __METHOD__ );
 184                                 if ( $toMaster ) {
 185                                         $id = $dbw->selectField( 'revision', 'rev_id', array( 'rev_id' => $rid ),
 186                                                 __METHOD__, 'FOR UPDATE' );
 187                                         if ( $id ) {
 188                                                 $this->output( "Revision already exists\n" );
 189                                                 $found = false;
 190                                                 break;
 191                                         } else {
 192                                                 $dbw->insert( 'revision', get_object_vars( $row ), __METHOD__, 'IGNORE' );
 193                                         }
 194                                 } else {
 195                                         foreach ( $this->slaveIndexes as $i ) {
 196                                                 $db = wfGetDB( $i );
 197                                                 $db->insert( 'revision', get_object_vars( $row ), __METHOD__, 'IGNORE' );
 198                                         }
 199                                 }
 200
 201                                 # Text
 202                                 $row = $dbFrom->selectRow( 'text', '*', array( 'old_id' => $row->rev_text_id ), __METHOD__ );
 203                                 if ( $toMaster ) {
 204                                         $dbw->insert( 'text', get_object_vars( $row ), __METHOD__, 'IGNORE' );
 205                                 } else {
 206                                         foreach ( $this->slaveIndexes as $i ) {
 207                                                 $db = wfGetDB( $i );
 208                                                 $db->insert( 'text', get_object_vars( $row ), __METHOD__, 'IGNORE' );
 209                                         }
 210                                 }
 211                         }
 212                         $this->output( "done\n" );
 213                 }
 214
 215                 if ( $found ) {
 216                         $this->output( "Fixing page_latest... " );
 217                         if ( $toMaster ) {
 218                                 /*
 219                                 $dbw->update(
 220                                         'page',
 221                                         array( 'page_latest' => $realLatest ),
 222                                         array( 'page_id' => $pageID ),
 223                                         __METHOD__
 224                                 );
 225                                 */
 226                         } else {
 227                                 foreach ( $this->slaveIndexes as $i ) {
 228                                         $db = wfGetDB( $i );
 229                                         $db->update(
 230                                                 'page',
 231                                                 array( 'page_latest' => $realLatest ),
 232                                                 array( 'page_id' => $pageID ),
 233                                                 __METHOD__
 234                                         );
 235                                 }
 236                         }
 237                         $this->output( "done\n" );
 238                 }
 239                 $dbw->commit( __METHOD__ );
 240         }
 241 }
 242
 243 $maintClass = "FixSlaveDesync";
 244 require_once RUN_MAINTENANCE_IF_MAIN;