}
/**
- * @todo document (e.g. one-sentence top-level class description).
+ * Class to both describe a background job and handle jobs.
*/
abstract class Job {
var $command,
$removeDuplicates,
$error;
+ /*-------------------------------------------------------------------------
+ * Abstract functions
+ *------------------------------------------------------------------------*/
+
+ /**
+ * Run the job
+ * @return boolean success
+ */
+ abstract function run();
+
/*-------------------------------------------------------------------------
* Static functions
*------------------------------------------------------------------------*/
- /**
+ /**
* @deprecated use LinksUpdate::queueRecursiveJobs()
*/
/**
/* Get a job from the slave, start with an offset,
scan full set afterwards, avoid hitting purged rows
-
+
NB: If random fetch previously was used, offset
will always be ahead of few entries
*/
-
+
$row = $dbr->selectRow( 'job', '*', "job_id >= ${offset}", __METHOD__,
array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
-
+
// Refetching without offset is needed as some of job IDs could have had delayed commits
// and have lower IDs than jobs already executed, blame concurrency :)
- //
+ //
if ( $row === false) {
if ($offset!=0)
$row = $dbr->selectRow( 'job', '*', '', __METHOD__,
array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
-
+
if ($row === false ) {
wfProfileOut( __METHOD__ );
return false;
- }
- }
+ }
+ }
$offset = $row->job_id;
-
+
// Try to delete it from the master
$dbw = wfGetDB( DB_MASTER );
$dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
$dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
$affected = $dbw->affectedRows();
$dbw->immediateCommit();
-
+
if ( !$affected ) {
// Random job gone before we exclusively deleted it
// Give up
return false;
}
}
-
+
// If execution got to here, there's a row in $row that has been deleted from the database
// by this thread. Hence the concurrent pop was successful.
$namespace = $row->job_namespace;
$dbkey = $row->job_title;
$title = Title::makeTitleSafe( $namespace, $dbkey );
$job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), $row->job_id );
-
+
// Remove any duplicates it may have later in the queue
$dbw->delete( 'job', $job->insertFields(), __METHOD__ );
-
+
wfProfileOut( __METHOD__ );
return $job;
}
- /**
+ /**
* Create an object of a subclass
*/
static function factory( $command, $title, $params = false, $id = 0 ) {
}
}
+ /**
+ * Batch-insert a group of jobs into the queue.
+ * This will be wrapped in a transaction with a forced commit.
+ *
+ * This may add duplicate at insert time, but they will be
+ * removed later on, when the first one is popped.
+ *
+ * @param $jobs array of Job objects
+ */
+ static function batchInsert( $jobs ) {
+ if( count( $jobs ) ) {
+ $dbw = wfGetDB( DB_MASTER );
+ $dbw->begin();
+ foreach( $jobs as $job ) {
+ $rows[] = $job->insertFields();
+ }
+ $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' );
+ $dbw->commit();
+ }
+ }
+
/*-------------------------------------------------------------------------
* Non-static functions
*------------------------------------------------------------------------*/
$fields = $this->insertFields();
$dbw = wfGetDB( DB_MASTER );
-
+
if ( $this->removeDuplicates ) {
$res = $dbw->select( 'job', array( '1' ), $fields, __METHOD__ );
if ( $dbw->numRows( $res ) ) {
$fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' );
$dbw->insert( 'job', $fields, __METHOD__ );
}
-
+
protected function insertFields() {
return array(
'job_cmd' => $this->command,
'job_params' => Job::makeBlob( $this->params )
);
}
-
- /**
- * Batch-insert a group of jobs into the queue.
- * This will be wrapped in a transaction with a forced commit.
- *
- * This may add duplicate at insert time, but they will be
- * removed later on, when the first one is popped.
- *
- * @param $jobs array of Job objects
- */
- static function batchInsert( $jobs ) {
- if( count( $jobs ) ) {
- $dbw = wfGetDB( DB_MASTER );
- $dbw->begin();
- foreach( $jobs as $job ) {
- $rows[] = $job->insertFields();
- }
- $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' );
- $dbw->commit();
- }
- }
- /**
- * Run the job
- * @return boolean success
- */
- abstract function run();
-
function toString() {
$paramString = '';
if ( $this->params ) {
/**
- * @todo document (e.g. one-sentence top-level class description).
+ * Background job to update links for a given title.
*/
class RefreshLinksJob extends Job {
function __construct( $title, $params = '', $id = 0 ) {
$linkCache =& LinkCache::singleton();
$linkCache->clear();
-
+
if ( is_null( $this->title ) ) {
$this->error = "refreshLinks: Invalid title";
wfProfileOut( __METHOD__ );