aa21e125a3
Xhprof generates this data now. Custom profiling of various sub-function units are kept. Calls to profiler represented about 3% of page execution time on Special:BlankPage (1.5% in/out); after this change it's down to about 0.98% of page execution time. Change-Id: Id9a1dc9d8f80bbd52e42226b724a1e1213d07af7
362 lines
12 KiB
PHP
362 lines
12 KiB
PHP
<?php
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/**
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* Job queue runner utility methods
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @ingroup JobQueue
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*/
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/**
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* Job queue runner utility methods
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*
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* @ingroup JobQueue
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* @since 1.24
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*/
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class JobRunner {
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/** @var callable|null Debug output handler */
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protected $debug;
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/**
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* @param callable $debug Optional debug output handler
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*/
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public function setDebugHandler( $debug ) {
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$this->debug = $debug;
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}
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/**
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* Run jobs of the specified number/type for the specified time
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*
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* The response map has a 'job' field that lists status of each job, including:
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* - type : the job type
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* - status : ok/failed
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* - error : any error message string
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* - time : the job run time in ms
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* The response map also has:
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* - backoffs : the (job type => seconds) map of backoff times
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* - elapsed : the total time spent running tasks in ms
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* - reached : the reason the script finished, one of (none-ready, job-limit, time-limit)
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*
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* This method outputs status information only if a debug handler was set.
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* Any exceptions are caught and logged, but are not reported as output.
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*
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* @param array $options Map of parameters:
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* - type : the job type (or false for the default types)
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* - maxJobs : maximum number of jobs to run
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* - maxTime : maximum time in seconds before stopping
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* - throttle : whether to respect job backoff configuration
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* @return array Summary response that can easily be JSON serialized
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*/
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public function run( array $options ) {
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$response = array( 'jobs' => array(), 'reached' => 'none-ready' );
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$type = isset( $options['type'] ) ? $options['type'] : false;
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$maxJobs = isset( $options['maxJobs'] ) ? $options['maxJobs'] : false;
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$maxTime = isset( $options['maxTime'] ) ? $options['maxTime'] : false;
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$noThrottle = isset( $options['throttle'] ) && !$options['throttle'];
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$group = JobQueueGroup::singleton();
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// Handle any required periodic queue maintenance
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$count = $group->executeReadyPeriodicTasks();
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if ( $count > 0 ) {
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$this->runJobsLog( "Executed $count periodic queue task(s)." );
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}
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// Bail out if there is too much DB lag
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list( , $maxLag ) = wfGetLBFactory()->getMainLB( wfWikiID() )->getMaxLag();
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if ( $maxLag >= 5 ) {
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$response['reached'] = 'slave-lag-limit';
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return $response;
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}
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// Flush any pending DB writes for sanity
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wfGetLBFactory()->commitMasterChanges();
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// Some jobs types should not run until a certain timestamp
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$backoffs = array(); // map of (type => UNIX expiry)
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$backoffDeltas = array(); // map of (type => seconds)
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$wait = 'wait'; // block to read backoffs the first time
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$jobsRun = 0;
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$timeMsTotal = 0;
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$flags = JobQueueGroup::USE_CACHE;
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$checkPeriod = 5.0; // seconds
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$checkPhase = mt_rand( 0, 1000 * $checkPeriod ) / 1000; // avoid stampedes
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$startTime = microtime( true ); // time since jobs started running
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$lastTime = microtime( true ) - $checkPhase; // time since last slave check
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do {
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// Sync the persistent backoffs with concurrent runners
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$backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
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$blacklist = $noThrottle ? array() : array_keys( $backoffs );
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$wait = 'nowait'; // less important now
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if ( $type === false ) {
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$job = $group->pop( JobQueueGroup::TYPE_DEFAULT, $flags, $blacklist );
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} elseif ( in_array( $type, $blacklist ) ) {
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$job = false; // requested queue in backoff state
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} else {
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$job = $group->pop( $type ); // job from a single queue
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}
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if ( $job ) { // found a job
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$jType = $job->getType();
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// Back off of certain jobs for a while (for throttling and for errors)
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$ttw = $this->getBackoffTimeToWait( $job );
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if ( $ttw > 0 ) {
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// Always add the delta for other runners in case the time running the
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// job negated the backoff for each individually but not collectively.
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$backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
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? $backoffDeltas[$jType] + $ttw
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: $ttw;
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$backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
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}
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$this->runJobsLog( $job->toString() . " STARTING" );
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// Run the job...
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wfProfileIn( __METHOD__ . '-' . get_class( $job ) );
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$jobStartTime = microtime( true );
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try {
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++$jobsRun;
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$status = $job->run();
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$error = $job->getLastError();
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wfGetLBFactory()->commitMasterChanges();
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} catch ( MWException $e ) {
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MWExceptionHandler::rollbackMasterChangesAndLog( $e );
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$status = false;
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$error = get_class( $e ) . ': ' . $e->getMessage();
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MWExceptionHandler::logException( $e );
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}
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$timeMs = intval( ( microtime( true ) - $jobStartTime ) * 1000 );
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wfProfileOut( __METHOD__ . '-' . get_class( $job ) );
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$timeMsTotal += $timeMs;
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// Mark the job as done on success or when the job cannot be retried
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if ( $status !== false || !$job->allowRetries() ) {
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$group->ack( $job ); // done
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}
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// Back off of certain jobs for a while (for throttling and for errors)
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if ( $status === false && mt_rand( 0, 49 ) == 0 ) {
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$ttw = max( $ttw, 30 ); // too many errors
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$backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
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? $backoffDeltas[$jType] + $ttw
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: $ttw;
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}
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if ( $status === false ) {
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$this->runJobsLog( $job->toString() . " t=$timeMs error={$error}" );
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} else {
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$this->runJobsLog( $job->toString() . " t=$timeMs good" );
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}
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$response['jobs'][] = array(
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'type' => $jType,
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'status' => ( $status === false ) ? 'failed' : 'ok',
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'error' => $error,
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'time' => $timeMs
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);
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// Break out if we hit the job count or wall time limits...
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if ( $maxJobs && $jobsRun >= $maxJobs ) {
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$response['reached'] = 'job-limit';
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break;
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} elseif ( $maxTime && ( microtime( true ) - $startTime ) > $maxTime ) {
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$response['reached'] = 'time-limit';
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break;
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}
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// Don't let any of the main DB slaves get backed up.
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// This only waits for so long before exiting and letting
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// other wikis in the farm (on different masters) get a chance.
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$timePassed = microtime( true ) - $lastTime;
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if ( $timePassed >= 5 || $timePassed < 0 ) {
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if ( !wfWaitForSlaves( $lastTime, false, '*', 5 ) ) {
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$response['reached'] = 'slave-lag-limit';
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break;
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}
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$lastTime = microtime( true );
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}
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// Don't let any queue slaves/backups fall behind
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if ( $jobsRun > 0 && ( $jobsRun % 100 ) == 0 ) {
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$group->waitForBackups();
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}
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// Bail if near-OOM instead of in a job
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$this->assertMemoryOK();
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}
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} while ( $job ); // stop when there are no jobs
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// Sync the persistent backoffs for the next runJobs.php pass
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if ( $backoffDeltas ) {
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$this->syncBackoffDeltas( $backoffs, $backoffDeltas, 'wait' );
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}
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$response['backoffs'] = $backoffs;
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$response['elapsed'] = $timeMsTotal;
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return $response;
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}
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/**
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* @param Job $job
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* @return int Seconds for this runner to avoid doing more jobs of this type
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* @see $wgJobBackoffThrottling
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*/
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private function getBackoffTimeToWait( Job $job ) {
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global $wgJobBackoffThrottling;
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if ( !isset( $wgJobBackoffThrottling[$job->getType()] ) ||
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$job instanceof DuplicateJob // no work was done
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) {
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return 0; // not throttled
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}
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$itemsPerSecond = $wgJobBackoffThrottling[$job->getType()];
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if ( $itemsPerSecond <= 0 ) {
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return 0; // not throttled
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}
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$seconds = 0;
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if ( $job->workItemCount() > 0 ) {
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$exactSeconds = $job->workItemCount() / $itemsPerSecond;
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// use randomized rounding
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$seconds = floor( $exactSeconds );
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$remainder = $exactSeconds - $seconds;
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$seconds += ( mt_rand() / mt_getrandmax() < $remainder ) ? 1 : 0;
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}
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return (int)$seconds;
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}
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/**
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* Get the previous backoff expiries from persistent storage
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* On I/O or lock acquisition failure this returns the original $backoffs.
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*
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* @param array $backoffs Map of (job type => UNIX timestamp)
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* @param string $mode Lock wait mode - "wait" or "nowait"
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* @return array Map of (job type => backoff expiry timestamp)
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*/
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private function loadBackoffs( array $backoffs, $mode = 'wait' ) {
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$file = wfTempDir() . '/mw-runJobs-backoffs.json';
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if ( is_file( $file ) ) {
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$noblock = ( $mode === 'nowait' ) ? LOCK_NB : 0;
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$handle = fopen( $file, 'rb' );
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if ( !flock( $handle, LOCK_SH | $noblock ) ) {
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fclose( $handle );
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return $backoffs; // don't wait on lock
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}
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$content = stream_get_contents( $handle );
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flock( $handle, LOCK_UN );
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fclose( $handle );
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$ctime = microtime( true );
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$cBackoffs = json_decode( $content, true ) ?: array();
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foreach ( $cBackoffs as $type => $timestamp ) {
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if ( $timestamp < $ctime ) {
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unset( $cBackoffs[$type] );
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}
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}
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} else {
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$cBackoffs = array();
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}
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return $cBackoffs;
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}
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/**
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* Merge the current backoff expiries from persistent storage
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*
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* The $deltas map is set to an empty array on success.
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* On I/O or lock acquisition failure this returns the original $backoffs.
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*
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* @param array $backoffs Map of (job type => UNIX timestamp)
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* @param array $deltas Map of (job type => seconds)
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* @param string $mode Lock wait mode - "wait" or "nowait"
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* @return array The new backoffs account for $backoffs and the latest file data
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*/
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private function syncBackoffDeltas( array $backoffs, array &$deltas, $mode = 'wait' ) {
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if ( !$deltas ) {
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return $this->loadBackoffs( $backoffs, $mode );
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}
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$noblock = ( $mode === 'nowait' ) ? LOCK_NB : 0;
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$file = wfTempDir() . '/mw-runJobs-backoffs.json';
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$handle = fopen( $file, 'wb+' );
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if ( !flock( $handle, LOCK_EX | $noblock ) ) {
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fclose( $handle );
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return $backoffs; // don't wait on lock
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}
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$ctime = microtime( true );
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$content = stream_get_contents( $handle );
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$cBackoffs = json_decode( $content, true ) ?: array();
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foreach ( $deltas as $type => $seconds ) {
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$cBackoffs[$type] = isset( $cBackoffs[$type] ) && $cBackoffs[$type] >= $ctime
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? $cBackoffs[$type] + $seconds
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: $ctime + $seconds;
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}
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foreach ( $cBackoffs as $type => $timestamp ) {
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if ( $timestamp < $ctime ) {
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unset( $cBackoffs[$type] );
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}
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}
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ftruncate( $handle, 0 );
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fwrite( $handle, json_encode( $cBackoffs ) );
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flock( $handle, LOCK_UN );
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fclose( $handle );
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$deltas = array();
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return $cBackoffs;
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}
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/**
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* Make sure that this script is not too close to the memory usage limit.
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* It is better to die in between jobs than OOM right in the middle of one.
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* @throws MWException
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*/
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private function assertMemoryOK() {
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static $maxBytes = null;
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if ( $maxBytes === null ) {
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$m = array();
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if ( preg_match( '!^(\d+)(k|m|g|)$!i', ini_get( 'memory_limit' ), $m ) ) {
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list( , $num, $unit ) = $m;
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$conv = array( 'g' => 1073741824, 'm' => 1048576, 'k' => 1024, '' => 1 );
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$maxBytes = $num * $conv[strtolower( $unit )];
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} else {
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$maxBytes = 0;
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}
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}
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$usedBytes = memory_get_usage();
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if ( $maxBytes && $usedBytes >= 0.95 * $maxBytes ) {
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throw new MWException( "Detected excessive memory usage ($usedBytes/$maxBytes)." );
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}
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}
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/**
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* Log the job message
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* @param string $msg The message to log
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*/
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private function runJobsLog( $msg ) {
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if ( $this->debug ) {
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call_user_func_array( $this->debug, array( wfTimestamp( TS_DB ) . " $msg\n" ) );
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}
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wfDebugLog( 'runJobs', $msg );
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}
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}
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