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-rw-r--r--includes/JobQueue.php125
1 files changed, 76 insertions, 49 deletions
diff --git a/includes/JobQueue.php b/includes/JobQueue.php
index 746cf5de..140130fa 100644
--- a/includes/JobQueue.php
+++ b/includes/JobQueue.php
@@ -4,6 +4,9 @@ if ( !defined( 'MEDIAWIKI' ) ) {
die( "This file is part of MediaWiki, it is not a valid entry point\n" );
}
+/**
+ * Class to both describe a background job and handle jobs.
+ */
abstract class Job {
var $command,
$title,
@@ -13,10 +16,20 @@ abstract class Job {
$error;
/*-------------------------------------------------------------------------
+ * Abstract functions
+ *------------------------------------------------------------------------*/
+
+ /**
+ * Run the job
+ * @return boolean success
+ */
+ abstract function run();
+
+ /*-------------------------------------------------------------------------
* Static functions
*------------------------------------------------------------------------*/
- /**
+ /**
* @deprecated use LinksUpdate::queueRecursiveJobs()
*/
/**
@@ -26,25 +39,41 @@ abstract class Job {
/**
* Pop a job off the front of the queue
* @static
+ * @param $offset Number of jobs to skip
* @return Job or false if there's no jobs
*/
- static function pop() {
+ static function pop($offset=0) {
wfProfileIn( __METHOD__ );
- $dbr =& wfGetDB( DB_SLAVE );
+ $dbr = wfGetDB( DB_SLAVE );
- // Get a job from the slave
- $row = $dbr->selectRow( 'job', '*', '', __METHOD__,
- array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 )
- );
+ /* Get a job from the slave, start with an offset,
+ scan full set afterwards, avoid hitting purged rows
- if ( $row === false ) {
- wfProfileOut( __METHOD__ );
- return false;
+ 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 = wfGetDB( DB_MASTER );
$dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
$affected = $dbw->affectedRows();
$dbw->immediateCommit();
@@ -53,7 +82,7 @@ abstract class Job {
// Failed, someone else beat us to it
// Try getting a random row
$row = $dbw->selectRow( 'job', array( 'MIN(job_id) as minjob',
- 'MAX(job_id) as maxjob' ), '', __METHOD__ );
+ 'MAX(job_id) as maxjob' ), "job_id >= $offset", __METHOD__ );
if ( $row === false || is_null( $row->minjob ) || is_null( $row->maxjob ) ) {
// No jobs to get
wfProfileOut( __METHOD__ );
@@ -61,7 +90,7 @@ abstract class Job {
}
// Get the random row
$row = $dbw->selectRow( 'job', '*',
- array( 'job_id' => mt_rand( $row->minjob, $row->maxjob ) ), __METHOD__ );
+ 'job_id >= ' . mt_rand( $row->minjob, $row->maxjob ), __METHOD__ );
if ( $row === false ) {
// Random job gone before we got the chance to select it
// Give up
@@ -72,7 +101,7 @@ abstract class Job {
$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
@@ -80,22 +109,22 @@ abstract class Job {
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 ) {
@@ -126,6 +155,27 @@ abstract class Job {
}
}
+ /**
+ * 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
*------------------------------------------------------------------------*/
@@ -147,8 +197,8 @@ abstract class Job {
function insert() {
$fields = $this->insertFields();
- $dbw =& wfGetDB( DB_MASTER );
-
+ $dbw = wfGetDB( DB_MASTER );
+
if ( $this->removeDuplicates ) {
$res = $dbw->select( 'job', array( '1' ), $fields, __METHOD__ );
if ( $dbw->numRows( $res ) ) {
@@ -158,7 +208,7 @@ abstract class Job {
$fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' );
$dbw->insert( 'job', $fields, __METHOD__ );
}
-
+
protected function insertFields() {
return array(
'job_cmd' => $this->command,
@@ -167,34 +217,7 @@ abstract class Job {
'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 ) {
@@ -222,6 +245,10 @@ abstract class Job {
}
}
+
+/**
+ * Background job to update links for a given title.
+ */
class RefreshLinksJob extends Job {
function __construct( $title, $params = '', $id = 0 ) {
parent::__construct( 'refreshLinks', $title, $params, $id );
@@ -237,7 +264,7 @@ class RefreshLinksJob extends Job {
$linkCache =& LinkCache::singleton();
$linkCache->clear();
-
+
if ( is_null( $this->title ) ) {
$this->error = "refreshLinks: Invalid title";
wfProfileOut( __METHOD__ );
generated by cgit v1.2.2 (git 2.25.0) at 2024-04-18 22:42:09 +0000