3 if ( !defined( 'MEDIAWIKI' ) ) {
4 die( "This file is part of MediaWiki, it is not a valid entry point\n" );
7 require_once('UserMailer.php');
10 * Class to both describe a background job and handle jobs.
20 /*-------------------------------------------------------------------------
22 *------------------------------------------------------------------------*/
26 * @return boolean success
28 abstract function run();
30 /*-------------------------------------------------------------------------
32 *------------------------------------------------------------------------*/
35 * @deprecated use LinksUpdate::queueRecursiveJobs()
38 * static function queueLinksJobs( $titles ) {}
42 * Pop a job of a certain type. This tries less hard than pop() to
43 * actually find a job; it may be adversely affected by concurrent job
46 static function pop_type($type) {
47 wfProfilein( __METHOD__
);
49 $dbw = wfGetDB( DB_MASTER
);
52 $row = $dbw->selectRow( 'job', '*', array( 'job_cmd' => $type ), __METHOD__
,
53 array( 'LIMIT' => 1 ));
56 wfProfileOut( __METHOD__
);
60 /* Ensure we "own" this row */
61 $dbw->delete( 'job', array( 'job_id' => $row->job_id
), __METHOD__
);
62 $affected = $dbw->affectedRows();
65 wfProfileOut( __METHOD__
);
69 $namespace = $row->job_namespace
;
70 $dbkey = $row->job_title
;
71 $title = Title
::makeTitleSafe( $namespace, $dbkey );
72 $job = Job
::factory( $row->job_cmd
, $title, Job
::extractBlob( $row->job_params
), $row->job_id
);
74 $dbw->delete( 'job', $job->insertFields(), __METHOD__
);
75 $dbw->immediateCommit();
77 wfProfileOut( __METHOD__
);
82 * Pop a job off the front of the queue
84 * @param $offset Number of jobs to skip
85 * @return Job or false if there's no jobs
87 static function pop($offset=0) {
88 wfProfileIn( __METHOD__
);
90 $dbr = wfGetDB( DB_SLAVE
);
92 /* Get a job from the slave, start with an offset,
93 scan full set afterwards, avoid hitting purged rows
95 NB: If random fetch previously was used, offset
96 will always be ahead of few entries
99 $row = $dbr->selectRow( 'job', '*', "job_id >= ${offset}", __METHOD__
,
100 array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
102 // Refetching without offset is needed as some of job IDs could have had delayed commits
103 // and have lower IDs than jobs already executed, blame concurrency :)
105 if ( $row === false) {
107 $row = $dbr->selectRow( 'job', '*', '', __METHOD__
,
108 array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
110 if ($row === false ) {
111 wfProfileOut( __METHOD__
);
115 $offset = $row->job_id
;
117 // Try to delete it from the master
118 $dbw = wfGetDB( DB_MASTER
);
119 $dbw->delete( 'job', array( 'job_id' => $row->job_id
), __METHOD__
);
120 $affected = $dbw->affectedRows();
121 $dbw->immediateCommit();
124 // Failed, someone else beat us to it
125 // Try getting a random row
126 $row = $dbw->selectRow( 'job', array( 'MIN(job_id) as minjob',
127 'MAX(job_id) as maxjob' ), "job_id >= $offset", __METHOD__
);
128 if ( $row === false ||
is_null( $row->minjob
) ||
is_null( $row->maxjob
) ) {
130 wfProfileOut( __METHOD__
);
133 // Get the random row
134 $row = $dbw->selectRow( 'job', '*',
135 'job_id >= ' . mt_rand( $row->minjob
, $row->maxjob
), __METHOD__
);
136 if ( $row === false ) {
137 // Random job gone before we got the chance to select it
139 wfProfileOut( __METHOD__
);
142 // Delete the random row
143 $dbw->delete( 'job', array( 'job_id' => $row->job_id
), __METHOD__
);
144 $affected = $dbw->affectedRows();
145 $dbw->immediateCommit();
148 // Random job gone before we exclusively deleted it
150 wfProfileOut( __METHOD__
);
155 // If execution got to here, there's a row in $row that has been deleted from the database
156 // by this thread. Hence the concurrent pop was successful.
157 $namespace = $row->job_namespace
;
158 $dbkey = $row->job_title
;
159 $title = Title
::makeTitleSafe( $namespace, $dbkey );
160 $job = Job
::factory( $row->job_cmd
, $title, Job
::extractBlob( $row->job_params
), $row->job_id
);
162 // Remove any duplicates it may have later in the queue
163 $dbw->delete( 'job', $job->insertFields(), __METHOD__
);
165 wfProfileOut( __METHOD__
);
170 * Create the appropriate object to handle a specific job
172 * @param string $command Job command
173 * @param Title $title Associated title
174 * @param array $params Job parameters
175 * @param int $id Job identifier
178 static function factory( $command, $title, $params = false, $id = 0 ) {
179 global $wgJobClasses;
180 if( isset( $wgJobClasses[$command] ) ) {
181 $class = $wgJobClasses[$command];
182 return new $class( $title, $params, $id );
184 throw new MWException( "Invalid job command `{$command}`" );
187 static function makeBlob( $params ) {
188 if ( $params !== false ) {
189 return serialize( $params );
195 static function extractBlob( $blob ) {
196 if ( (string)$blob !== '' ) {
197 return unserialize( $blob );
204 * Batch-insert a group of jobs into the queue.
205 * This will be wrapped in a transaction with a forced commit.
207 * This may add duplicate at insert time, but they will be
208 * removed later on, when the first one is popped.
210 * @param $jobs array of Job objects
212 static function batchInsert( $jobs ) {
213 if( count( $jobs ) ) {
214 $dbw = wfGetDB( DB_MASTER
);
216 foreach( $jobs as $job ) {
217 $rows[] = $job->insertFields();
219 $dbw->insert( 'job', $rows, __METHOD__
, 'IGNORE' );
224 /*-------------------------------------------------------------------------
225 * Non-static functions
226 *------------------------------------------------------------------------*/
228 function __construct( $command, $title, $params = false, $id = 0 ) {
229 $this->command
= $command;
230 $this->title
= $title;
231 $this->params
= $params;
234 // A bit of premature generalisation
235 // Oh well, the whole class is premature generalisation really
236 $this->removeDuplicates
= true;
240 * Insert a single job into the queue.
243 $fields = $this->insertFields();
245 $dbw = wfGetDB( DB_MASTER
);
247 if ( $this->removeDuplicates
) {
248 $res = $dbw->select( 'job', array( '1' ), $fields, __METHOD__
);
249 if ( $dbw->numRows( $res ) ) {
253 $fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' );
254 $dbw->insert( 'job', $fields, __METHOD__
);
257 protected function insertFields() {
259 'job_cmd' => $this->command
,
260 'job_namespace' => $this->title
->getNamespace(),
261 'job_title' => $this->title
->getDBkey(),
262 'job_params' => Job
::makeBlob( $this->params
)
266 function toString() {
268 if ( $this->params
) {
269 foreach ( $this->params
as $key => $value ) {
270 if ( $paramString != '' ) {
273 $paramString .= "$key=$value";
277 if ( is_object( $this->title
) ) {
278 $s = "{$this->command} " . $this->title
->getPrefixedDBkey();
279 if ( $paramString !== '' ) {
280 $s .= ' ' . $paramString;
284 return "{$this->command} $paramString";
288 function getLastError() {