includes/JobQueue.php

   1 <?php
   2
   3 if ( !defined( 'MEDIAWIKI' ) ) {
   4         die( "This file is part of MediaWiki, it is not a valid entry point\n" );
   5 }
   6
   7 class Job {
   8         var $command,
   9                 $title,
  10                 $params,
  11                 $id,
  12                 $removeDuplicates,
  13                 $error;
  14
  15         /*-------------------------------------------------------------------------
  16          * Static functions
  17          *------------------------------------------------------------------------*/
  18         /**
  19          * Add an array of refreshLinks jobs to the queue
  20          * @param array $titles Array of title objects.
  21          * @static
  22          */
  23         function queueLinksJobs( $titles ) {
  24                 $fname = 'Job::queueLinksJobs';
  25                 wfProfileIn( $fname );
  26                 $batchSize = 100;
  27                 for( $i = 0; $i < count( $titles ); $i += $batchSize ) {
  28                         $batch = array_slice( $titles, $i, $batchSize, true );
  29                         $jobs = array();
  30                         foreach( $batch as $title ) {
  31                                 $jobs[] = new Job( 'refreshLinks', $title );
  32                         }
  33                         Job::batchInsert( $jobs );
  34                 }
  35                 wfProfileOut( $fname );
  36         }
  37
  38         /**
  39          * Pop a job off the front of the queue
  40          * @static
  41          * @return Job or false if there's no jobs
  42          */
  43         function pop() {
  44                 $fname = 'Job::pop';
  45                 wfProfileIn( $fname );
  46
  47                 $dbr =& wfGetDB( DB_SLAVE );
  48
  49                 // Get a job from the slave
  50                 $row = $dbr->selectRow( 'job', '*', '', $fname,
  51                         array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 )
  52                 );
  53
  54                 if ( $row === false ) {
  55                         wfProfileOut( $fname );
  56                         return false;
  57                 }
  58
  59                 // Try to delete it from the master
  60                 $dbw =& wfGetDB( DB_MASTER );
  61                 $dbw->delete( 'job', array( 'job_id' => $row->job_id ), $fname );
  62                 $affected = $dbw->affectedRows();
  63                 $dbw->immediateCommit();
  64
  65                 if ( !$affected ) {
  66                         // Failed, someone else beat us to it
  67                         // Try getting a random row
  68                         $row = $dbw->selectRow( 'job', array( 'MIN(job_id) as minjob',
  69                                 'MAX(job_id) as maxjob' ), '', $fname );
  70                         if ( $row === false || is_null( $row->minjob ) || is_null( $row->maxjob ) ) {
  71                                 // No jobs to get
  72                                 wfProfileOut( $fname );
  73                                 return false;
  74                         }
  75                         // Get the random row
  76                         $row = $dbw->selectRow( 'job', '*',
  77                                 array( 'job_id' => mt_rand( $row->minjob, $row->maxjob ) ),     $fname );
  78                         if ( $row === false ) {
  79                                 // Random job gone before we got the chance to select it
  80                                 // Give up
  81                                 wfProfileOut( $fname );
  82                                 return false;
  83                         }
  84                         // Delete the random row
  85                         $dbw->delete( 'job', array( 'job_id' => $row->job_id ), $fname );
  86                         $affected = $dbw->affectedRows();
  87                         $dbw->immediateCommit();
  88
  89                         if ( !$affected ) {
  90                                 // Random job gone before we exclusively deleted it
  91                                 // Give up
  92                                 wfProfileOut( $fname );
  93                                 return false;
  94                         }
  95                 }
  96
  97                 // If execution got to here, there's a row in $row that has been deleted from the database
  98                 // by this thread. Hence the concurrent pop was successful.
  99                 $namespace = $row->job_namespace;
 100                 $dbkey = $row->job_title;
 101                 $title = Title::makeTitleSafe( $namespace, $dbkey );
 102                 $job = new Job( $row->job_cmd, $title, $row->job_params, $row->job_id );
 103
 104                 // Remove any duplicates it may have later in the queue
 105                 $dbw->delete( 'job', $job->insertFields(), $fname );
 106
 107                 wfProfileOut( $fname );
 108                 return $job;
 109         }
 110
 111         /*-------------------------------------------------------------------------
 112          * Non-static functions
 113          *------------------------------------------------------------------------*/
 114
 115         function Job( $command, $title, $params = '', $id = 0 ) {
 116                 $this->command = $command;
 117                 $this->title = $title;
 118                 $this->params = $params;
 119                 $this->id = $id;
 120
 121                 // A bit of premature generalisation
 122                 // Oh well, the whole class is premature generalisation really
 123                 $this->removeDuplicates = true;
 124         }
 125
 126         /**
 127          * Insert a single job into the queue.
 128          */
 129         function insert() {
 130                 $fname = 'Job::insert';
 131
 132                 $fields = $this->insertFields();
 133
 134                 $dbw =& wfGetDB( DB_MASTER );
 135
 136                 if ( $this->removeDuplicates ) {
 137                         $res = $dbw->select( 'job', array( '1' ), $fields, $fname );
 138                         if ( $dbw->numRows( $res ) ) {
 139                                 return;
 140                         }
 141                 }
 142                 $fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' );
 143                 $dbw->insert( 'job', $fields, $fname );
 144         }
 145
 146         protected function insertFields() {
 147                 return array(
 148                         'job_cmd' => $this->command,
 149                         'job_namespace' => $this->title->getNamespace(),
 150                         'job_title' => $this->title->getDBkey(),
 151                         'job_params' => $this->params
 152                 );
 153         }
 154
 155         /**
 156          * Batch-insert a group of jobs into the queue.
 157          * This will be wrapped in a transaction with a forced commit.
 158          *
 159          * This may add duplicate at insert time, but they will be
 160          * removed later on, when the first one is popped.
 161          *
 162          * @param $jobs array of Job objects
 163          */
 164         static function batchInsert( $jobs ) {
 165                 $fname = __CLASS__ . '::' . __FUNCTION__;
 166
 167                 if( count( $jobs ) ) {
 168                         $dbw = wfGetDB( DB_MASTER );
 169                         $dbw->begin();
 170                         foreach( $jobs as $job ) {
 171                                 $rows[] = $job->insertFields();
 172                         }
 173                         $dbw->insert( 'job', $rows, $fname, 'IGNORE' );
 174                         $dbw->immediateCommit();
 175                 }
 176         }
 177
 178         /**
 179          * Run the job
 180          * @return boolean success
 181          */
 182         function run() {
 183                 $fname = 'Job::run';
 184                 wfProfileIn( $fname );
 185                 switch ( $this->command ) {
 186                         case 'refreshLinks':
 187                                 $retval = $this->refreshLinks();
 188                                 break;
 189                         default:
 190                                 $this->error = "Invalid job type {$this->command}, ignoring";
 191                                 wfDebug( $this->error . "\n" );
 192                                 $retval = false;
 193                 }
 194                 wfProfileOut( $fname );
 195                 return $retval;
 196         }
 197
 198         /**
 199          * Run a refreshLinks job
 200          * @return boolean success
 201          */
 202         function refreshLinks() {
 203                 global $wgParser;
 204                 $fname = 'Job::refreshLinks';
 205                 wfProfileIn( $fname );
 206
 207                 # FIXME: $dbw never used.
 208                 $dbw =& wfGetDB( DB_MASTER );
 209
 210                 $linkCache =& LinkCache::singleton();
 211                 $linkCache->clear();
 212
 213                 if ( is_null( $this->title ) ) {
 214                         $this->error = "refreshLinks: Invalid title";
 215                         wfProfileOut( $fname );
 216                         return false;
 217                 }
 218
 219                 $revision = Revision::newFromTitle( $this->title );
 220                 if ( !$revision ) {
 221                         $this->error = 'refreshLinks: Article not found "' . $this->title->getPrefixedDBkey() . '"';
 222                         wfProfileOut( $fname );
 223                         return false;
 224                 }
 225
 226                 wfProfileIn( "$fname-parse" );
 227                 $options = new ParserOptions;
 228                 $parserOutput = $wgParser->parse( $revision->getText(), $this->title, $options, true, true, $revision->getId() );
 229                 wfProfileOut( "$fname-parse" );
 230                 wfProfileIn( "$fname-update" );
 231                 $update = new LinksUpdate( $this->title, $parserOutput, false );
 232                 $update->doUpdate();
 233                 wfProfileOut( "$fname-update" );
 234                 wfProfileOut( $fname );
 235                 return true;
 236         }
 237
 238         function toString() {
 239                 if ( is_object( $this->title ) ) {
 240                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 241                         if ( $this->params !== '' ) {
 242                                 $s .= ', ' . $this->params;
 243                         }
 244                         return $s;
 245                 } else {
 246                         return "{$this->command} {$this->params}";
 247                 }
 248         }
 249
 250         function getLastError() {
 251                 return $this->error;
 252         }
 253 }
 254 ?>