MediaWiki  REL1_31
JobQueueRedis.php
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1 <?php
22 use Psr\Log\LoggerInterface;
23 
66 class JobQueueRedis extends JobQueue {
68  protected $redisPool;
70  protected $logger;
71 
73  protected $server;
75  protected $compression;
76 
77  const MAX_PUSH_SIZE = 25; // avoid tying up the server
78 
92  public function __construct( array $params ) {
93  parent::__construct( $params );
94  $params['redisConfig']['serializer'] = 'none'; // make it easy to use Lua
95  $this->server = $params['redisServer'];
96  $this->compression = isset( $params['compression'] ) ? $params['compression'] : 'none';
97  $this->redisPool = RedisConnectionPool::singleton( $params['redisConfig'] );
98  if ( empty( $params['daemonized'] ) ) {
99  throw new InvalidArgumentException(
100  "Non-daemonized mode is no longer supported. Please install the " .
101  "mediawiki/services/jobrunner service and update \$wgJobTypeConf as needed." );
102  }
103  $this->logger = \MediaWiki\Logger\LoggerFactory::getInstance( 'redis' );
104  }
105 
106  protected function supportedOrders() {
107  return [ 'timestamp', 'fifo' ];
108  }
109 
110  protected function optimalOrder() {
111  return 'fifo';
112  }
113 
114  protected function supportsDelayedJobs() {
115  return true;
116  }
117 
123  protected function doIsEmpty() {
124  return $this->doGetSize() == 0;
125  }
126 
132  protected function doGetSize() {
133  $conn = $this->getConnection();
134  try {
135  return $conn->lLen( $this->getQueueKey( 'l-unclaimed' ) );
136  } catch ( RedisException $e ) {
137  $this->throwRedisException( $conn, $e );
138  }
139  }
140 
146  protected function doGetAcquiredCount() {
147  $conn = $this->getConnection();
148  try {
149  $conn->multi( Redis::PIPELINE );
150  $conn->zSize( $this->getQueueKey( 'z-claimed' ) );
151  $conn->zSize( $this->getQueueKey( 'z-abandoned' ) );
152 
153  return array_sum( $conn->exec() );
154  } catch ( RedisException $e ) {
155  $this->throwRedisException( $conn, $e );
156  }
157  }
158 
164  protected function doGetDelayedCount() {
165  $conn = $this->getConnection();
166  try {
167  return $conn->zSize( $this->getQueueKey( 'z-delayed' ) );
168  } catch ( RedisException $e ) {
169  $this->throwRedisException( $conn, $e );
170  }
171  }
172 
178  protected function doGetAbandonedCount() {
179  $conn = $this->getConnection();
180  try {
181  return $conn->zSize( $this->getQueueKey( 'z-abandoned' ) );
182  } catch ( RedisException $e ) {
183  $this->throwRedisException( $conn, $e );
184  }
185  }
186 
194  protected function doBatchPush( array $jobs, $flags ) {
195  // Convert the jobs into field maps (de-duplicated against each other)
196  $items = []; // (job ID => job fields map)
197  foreach ( $jobs as $job ) {
198  $item = $this->getNewJobFields( $job );
199  if ( strlen( $item['sha1'] ) ) { // hash identifier => de-duplicate
200  $items[$item['sha1']] = $item;
201  } else {
202  $items[$item['uuid']] = $item;
203  }
204  }
205 
206  if ( !count( $items ) ) {
207  return; // nothing to do
208  }
209 
210  $conn = $this->getConnection();
211  try {
212  // Actually push the non-duplicate jobs into the queue...
213  if ( $flags & self::QOS_ATOMIC ) {
214  $batches = [ $items ]; // all or nothing
215  } else {
216  $batches = array_chunk( $items, self::MAX_PUSH_SIZE );
217  }
218  $failed = 0;
219  $pushed = 0;
220  foreach ( $batches as $itemBatch ) {
221  $added = $this->pushBlobs( $conn, $itemBatch );
222  if ( is_int( $added ) ) {
223  $pushed += $added;
224  } else {
225  $failed += count( $itemBatch );
226  }
227  }
228  JobQueue::incrStats( 'inserts', $this->type, count( $items ) );
229  JobQueue::incrStats( 'inserts_actual', $this->type, $pushed );
230  JobQueue::incrStats( 'dupe_inserts', $this->type,
231  count( $items ) - $failed - $pushed );
232  if ( $failed > 0 ) {
233  $err = "Could not insert {$failed} {$this->type} job(s).";
234  wfDebugLog( 'JobQueueRedis', $err );
235  throw new RedisException( $err );
236  }
237  } catch ( RedisException $e ) {
238  $this->throwRedisException( $conn, $e );
239  }
240  }
241 
248  protected function pushBlobs( RedisConnRef $conn, array $items ) {
249  $args = [ $this->encodeQueueName() ];
250  // Next args come in 4s ([id, sha1, rtime, blob [, id, sha1, rtime, blob ... ] ] )
251  foreach ( $items as $item ) {
252  $args[] = (string)$item['uuid'];
253  $args[] = (string)$item['sha1'];
254  $args[] = (string)$item['rtimestamp'];
255  $args[] = (string)$this->serialize( $item );
256  }
257  static $script =
259 <<<LUA
260  local kUnclaimed, kSha1ById, kIdBySha1, kDelayed, kData, kQwJobs = unpack(KEYS)
261  -- First argument is the queue ID
262  local queueId = ARGV[1]
263  -- Next arguments all come in 4s (one per job)
264  local variadicArgCount = #ARGV - 1
265  if variadicArgCount % 4 ~= 0 then
266  return redis.error_reply('Unmatched arguments')
267  end
268  -- Insert each job into this queue as needed
269  local pushed = 0
270  for i = 2,#ARGV,4 do
271  local id,sha1,rtimestamp,blob = ARGV[i],ARGV[i+1],ARGV[i+2],ARGV[i+3]
272  if sha1 == '' or redis.call('hExists',kIdBySha1,sha1) == 0 then
273  if 1*rtimestamp > 0 then
274  -- Insert into delayed queue (release time as score)
275  redis.call('zAdd',kDelayed,rtimestamp,id)
276  else
277  -- Insert into unclaimed queue
278  redis.call('lPush',kUnclaimed,id)
279  end
280  if sha1 ~= '' then
281  redis.call('hSet',kSha1ById,id,sha1)
282  redis.call('hSet',kIdBySha1,sha1,id)
283  end
284  redis.call('hSet',kData,id,blob)
285  pushed = pushed + 1
286  end
287  end
288  -- Mark this queue as having jobs
289  redis.call('sAdd',kQwJobs,queueId)
290  return pushed
291 LUA;
292  return $conn->luaEval( $script,
293  array_merge(
294  [
295  $this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
296  $this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
297  $this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
298  $this->getQueueKey( 'z-delayed' ), # KEYS[4]
299  $this->getQueueKey( 'h-data' ), # KEYS[5]
300  $this->getGlobalKey( 's-queuesWithJobs' ), # KEYS[6]
301  ],
302  $args
303  ),
304  6 # number of first argument(s) that are keys
305  );
306  }
307 
313  protected function doPop() {
314  $job = false;
315 
316  $conn = $this->getConnection();
317  try {
318  do {
319  $blob = $this->popAndAcquireBlob( $conn );
320  if ( !is_string( $blob ) ) {
321  break; // no jobs; nothing to do
322  }
323 
324  JobQueue::incrStats( 'pops', $this->type );
325  $item = $this->unserialize( $blob );
326  if ( $item === false ) {
327  wfDebugLog( 'JobQueueRedis', "Could not unserialize {$this->type} job." );
328  continue;
329  }
330 
331  // If $item is invalid, the runner loop recyling will cleanup as needed
332  $job = $this->getJobFromFields( $item ); // may be false
333  } while ( !$job ); // job may be false if invalid
334  } catch ( RedisException $e ) {
335  $this->throwRedisException( $conn, $e );
336  }
337 
338  return $job;
339  }
340 
346  protected function popAndAcquireBlob( RedisConnRef $conn ) {
347  static $script =
349 <<<LUA
350  local kUnclaimed, kSha1ById, kIdBySha1, kClaimed, kAttempts, kData = unpack(KEYS)
351  local rTime = unpack(ARGV)
352  -- Pop an item off the queue
353  local id = redis.call('rPop',kUnclaimed)
354  if not id then
355  return false
356  end
357  -- Allow new duplicates of this job
358  local sha1 = redis.call('hGet',kSha1ById,id)
359  if sha1 then redis.call('hDel',kIdBySha1,sha1) end
360  redis.call('hDel',kSha1ById,id)
361  -- Mark the jobs as claimed and return it
362  redis.call('zAdd',kClaimed,rTime,id)
363  redis.call('hIncrBy',kAttempts,id,1)
364  return redis.call('hGet',kData,id)
365 LUA;
366  return $conn->luaEval( $script,
367  [
368  $this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
369  $this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
370  $this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
371  $this->getQueueKey( 'z-claimed' ), # KEYS[4]
372  $this->getQueueKey( 'h-attempts' ), # KEYS[5]
373  $this->getQueueKey( 'h-data' ), # KEYS[6]
374  time(), # ARGV[1] (injected to be replication-safe)
375  ],
376  6 # number of first argument(s) that are keys
377  );
378  }
379 
387  protected function doAck( Job $job ) {
388  if ( !isset( $job->metadata['uuid'] ) ) {
389  throw new UnexpectedValueException( "Job of type '{$job->getType()}' has no UUID." );
390  }
391 
392  $uuid = $job->metadata['uuid'];
393  $conn = $this->getConnection();
394  try {
395  static $script =
397 <<<LUA
398  local kClaimed, kAttempts, kData = unpack(KEYS)
399  local id = unpack(ARGV)
400  -- Unmark the job as claimed
401  local removed = redis.call('zRem',kClaimed,id)
402  -- Check if the job was recycled
403  if removed == 0 then
404  return 0
405  end
406  -- Delete the retry data
407  redis.call('hDel',kAttempts,id)
408  -- Delete the job data itself
409  return redis.call('hDel',kData,id)
410 LUA;
411  $res = $conn->luaEval( $script,
412  [
413  $this->getQueueKey( 'z-claimed' ), # KEYS[1]
414  $this->getQueueKey( 'h-attempts' ), # KEYS[2]
415  $this->getQueueKey( 'h-data' ), # KEYS[3]
416  $uuid # ARGV[1]
417  ],
418  3 # number of first argument(s) that are keys
419  );
420 
421  if ( !$res ) {
422  wfDebugLog( 'JobQueueRedis', "Could not acknowledge {$this->type} job $uuid." );
423 
424  return false;
425  }
426 
427  JobQueue::incrStats( 'acks', $this->type );
428  } catch ( RedisException $e ) {
429  $this->throwRedisException( $conn, $e );
430  }
431 
432  return true;
433  }
434 
443  if ( !$job->hasRootJobParams() ) {
444  throw new LogicException( "Cannot register root job; missing parameters." );
445  }
446  $params = $job->getRootJobParams();
447 
448  $key = $this->getRootJobCacheKey( $params['rootJobSignature'] );
449 
450  $conn = $this->getConnection();
451  try {
452  $timestamp = $conn->get( $key ); // current last timestamp of this job
453  if ( $timestamp && $timestamp >= $params['rootJobTimestamp'] ) {
454  return true; // a newer version of this root job was enqueued
455  }
456 
457  // Update the timestamp of the last root job started at the location...
458  return $conn->set( $key, $params['rootJobTimestamp'], self::ROOTJOB_TTL ); // 2 weeks
459  } catch ( RedisException $e ) {
460  $this->throwRedisException( $conn, $e );
461  }
462  }
463 
470  protected function doIsRootJobOldDuplicate( Job $job ) {
471  if ( !$job->hasRootJobParams() ) {
472  return false; // job has no de-deplication info
473  }
474  $params = $job->getRootJobParams();
475 
476  $conn = $this->getConnection();
477  try {
478  // Get the last time this root job was enqueued
479  $timestamp = $conn->get( $this->getRootJobCacheKey( $params['rootJobSignature'] ) );
480  } catch ( RedisException $e ) {
481  $timestamp = false;
482  $this->throwRedisException( $conn, $e );
483  }
484 
485  // Check if a new root job was started at the location after this one's...
486  return ( $timestamp && $timestamp > $params['rootJobTimestamp'] );
487  }
488 
494  protected function doDelete() {
495  static $props = [ 'l-unclaimed', 'z-claimed', 'z-abandoned',
496  'z-delayed', 'h-idBySha1', 'h-sha1ById', 'h-attempts', 'h-data' ];
497 
498  $conn = $this->getConnection();
499  try {
500  $keys = [];
501  foreach ( $props as $prop ) {
502  $keys[] = $this->getQueueKey( $prop );
503  }
504 
505  $ok = ( $conn->del( $keys ) !== false );
506  $conn->sRem( $this->getGlobalKey( 's-queuesWithJobs' ), $this->encodeQueueName() );
507 
508  return $ok;
509  } catch ( RedisException $e ) {
510  $this->throwRedisException( $conn, $e );
511  }
512  }
513 
519  public function getAllQueuedJobs() {
520  $conn = $this->getConnection();
521  try {
522  $uids = $conn->lRange( $this->getQueueKey( 'l-unclaimed' ), 0, -1 );
523  } catch ( RedisException $e ) {
524  $this->throwRedisException( $conn, $e );
525  }
526 
527  return $this->getJobIterator( $conn, $uids );
528  }
529 
535  public function getAllDelayedJobs() {
536  $conn = $this->getConnection();
537  try {
538  $uids = $conn->zRange( $this->getQueueKey( 'z-delayed' ), 0, -1 );
539  } catch ( RedisException $e ) {
540  $this->throwRedisException( $conn, $e );
541  }
542 
543  return $this->getJobIterator( $conn, $uids );
544  }
545 
551  public function getAllAcquiredJobs() {
552  $conn = $this->getConnection();
553  try {
554  $uids = $conn->zRange( $this->getQueueKey( 'z-claimed' ), 0, -1 );
555  } catch ( RedisException $e ) {
556  $this->throwRedisException( $conn, $e );
557  }
558 
559  return $this->getJobIterator( $conn, $uids );
560  }
561 
567  public function getAllAbandonedJobs() {
568  $conn = $this->getConnection();
569  try {
570  $uids = $conn->zRange( $this->getQueueKey( 'z-abandoned' ), 0, -1 );
571  } catch ( RedisException $e ) {
572  $this->throwRedisException( $conn, $e );
573  }
574 
575  return $this->getJobIterator( $conn, $uids );
576  }
577 
583  protected function getJobIterator( RedisConnRef $conn, array $uids ) {
584  return new MappedIterator(
585  $uids,
586  function ( $uid ) use ( $conn ) {
587  return $this->getJobFromUidInternal( $uid, $conn );
588  },
589  [ 'accept' => function ( $job ) {
590  return is_object( $job );
591  } ]
592  );
593  }
594 
595  public function getCoalesceLocationInternal() {
596  return "RedisServer:" . $this->server;
597  }
598 
599  protected function doGetSiblingQueuesWithJobs( array $types ) {
600  return array_keys( array_filter( $this->doGetSiblingQueueSizes( $types ) ) );
601  }
602 
603  protected function doGetSiblingQueueSizes( array $types ) {
604  $sizes = []; // (type => size)
605  $types = array_values( $types ); // reindex
606  $conn = $this->getConnection();
607  try {
608  $conn->multi( Redis::PIPELINE );
609  foreach ( $types as $type ) {
610  $conn->lLen( $this->getQueueKey( 'l-unclaimed', $type ) );
611  }
612  $res = $conn->exec();
613  if ( is_array( $res ) ) {
614  foreach ( $res as $i => $size ) {
615  $sizes[$types[$i]] = $size;
616  }
617  }
618  } catch ( RedisException $e ) {
619  $this->throwRedisException( $conn, $e );
620  }
621 
622  return $sizes;
623  }
624 
634  public function getJobFromUidInternal( $uid, RedisConnRef $conn ) {
635  try {
636  $data = $conn->hGet( $this->getQueueKey( 'h-data' ), $uid );
637  if ( $data === false ) {
638  return false; // not found
639  }
640  $item = $this->unserialize( $data );
641  if ( !is_array( $item ) ) { // this shouldn't happen
642  throw new UnexpectedValueException( "Could not find job with ID '$uid'." );
643  }
644  $title = Title::makeTitle( $item['namespace'], $item['title'] );
645  $job = Job::factory( $item['type'], $title, $item['params'] );
646  $job->metadata['uuid'] = $item['uuid'];
647  $job->metadata['timestamp'] = $item['timestamp'];
648  // Add in attempt count for debugging at showJobs.php
649  $job->metadata['attempts'] = $conn->hGet( $this->getQueueKey( 'h-attempts' ), $uid );
650 
651  return $job;
652  } catch ( RedisException $e ) {
653  $this->throwRedisException( $conn, $e );
654  }
655  }
656 
662  public function getServerQueuesWithJobs() {
663  $queues = [];
664 
665  $conn = $this->getConnection();
666  try {
667  $set = $conn->sMembers( $this->getGlobalKey( 's-queuesWithJobs' ) );
668  foreach ( $set as $queue ) {
669  $queues[] = $this->decodeQueueName( $queue );
670  }
671  } catch ( RedisException $e ) {
672  $this->throwRedisException( $conn, $e );
673  }
674 
675  return $queues;
676  }
677 
682  protected function getNewJobFields( IJobSpecification $job ) {
683  return [
684  // Fields that describe the nature of the job
685  'type' => $job->getType(),
686  'namespace' => $job->getTitle()->getNamespace(),
687  'title' => $job->getTitle()->getDBkey(),
688  'params' => $job->getParams(),
689  // Some jobs cannot run until a "release timestamp"
690  'rtimestamp' => $job->getReleaseTimestamp() ?: 0,
691  // Additional job metadata
693  'sha1' => $job->ignoreDuplicates()
694  ? Wikimedia\base_convert( sha1( serialize( $job->getDeduplicationInfo() ) ), 16, 36, 31 )
695  : '',
696  'timestamp' => time() // UNIX timestamp
697  ];
698  }
699 
704  protected function getJobFromFields( array $fields ) {
705  $title = Title::makeTitle( $fields['namespace'], $fields['title'] );
706  $job = Job::factory( $fields['type'], $title, $fields['params'] );
707  $job->metadata['uuid'] = $fields['uuid'];
708  $job->metadata['timestamp'] = $fields['timestamp'];
709 
710  return $job;
711  }
712 
717  protected function serialize( array $fields ) {
718  $blob = serialize( $fields );
719  if ( $this->compression === 'gzip'
720  && strlen( $blob ) >= 1024
721  && function_exists( 'gzdeflate' )
722  ) {
723  $object = (object)[ 'blob' => gzdeflate( $blob ), 'enc' => 'gzip' ];
724  $blobz = serialize( $object );
725 
726  return ( strlen( $blobz ) < strlen( $blob ) ) ? $blobz : $blob;
727  } else {
728  return $blob;
729  }
730  }
731 
736  protected function unserialize( $blob ) {
737  $fields = unserialize( $blob );
738  if ( is_object( $fields ) ) {
739  if ( $fields->enc === 'gzip' && function_exists( 'gzinflate' ) ) {
740  $fields = unserialize( gzinflate( $fields->blob ) );
741  } else {
742  $fields = false;
743  }
744  }
745 
746  return is_array( $fields ) ? $fields : false;
747  }
748 
755  protected function getConnection() {
756  $conn = $this->redisPool->getConnection( $this->server, $this->logger );
757  if ( !$conn ) {
758  throw new JobQueueConnectionError(
759  "Unable to connect to redis server {$this->server}." );
760  }
761 
762  return $conn;
763  }
764 
770  protected function throwRedisException( RedisConnRef $conn, $e ) {
771  $this->redisPool->handleError( $conn, $e );
772  throw new JobQueueError( "Redis server error: {$e->getMessage()}\n" );
773  }
774 
778  private function encodeQueueName() {
779  return json_encode( [ $this->type, $this->wiki ] );
780  }
781 
786  private function decodeQueueName( $name ) {
787  return json_decode( $name );
788  }
789 
794  private function getGlobalKey( $name ) {
795  $parts = [ 'global', 'jobqueue', $name ];
796  foreach ( $parts as $part ) {
797  if ( !preg_match( '/[a-zA-Z0-9_-]+/', $part ) ) {
798  throw new InvalidArgumentException( "Key part characters are out of range." );
799  }
800  }
801 
802  return implode( ':', $parts );
803  }
804 
810  private function getQueueKey( $prop, $type = null ) {
811  $type = is_string( $type ) ? $type : $this->type;
812  list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
813  $keyspace = $prefix ? "$db-$prefix" : $db;
814 
815  $parts = [ $keyspace, 'jobqueue', $type, $prop ];
816 
817  // Parts are typically ASCII, but encode for sanity to escape ":"
818  return implode( ':', array_map( 'rawurlencode', $parts ) );
819  }
820 }
MappedIterator
Convenience class for generating iterators from iterators.
Definition: MappedIterator.php:28
object
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Definition: globals.txt:64
UIDGenerator\QUICK_RAND
const QUICK_RAND
Definition: UIDGenerator.php:45
type
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Definition: postgres.txt:30
RedisConnectionPool\singleton
static singleton(array $options)
Definition: RedisConnectionPool.php:147
JobQueue\incrStats
static incrStats( $key, $type, $delta=1)
Call wfIncrStats() for the queue overall and for the queue type.
Definition: JobQueue.php:709
use
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
Definition: APACHE-LICENSE-2.0.txt:10
JobQueueRedis\doGetAcquiredCount
doGetAcquiredCount()
Definition: JobQueueRedis.php:146
array
the array() calling protocol came about after MediaWiki 1.4rc1.
is
We use the convention $dbr for read and $dbw for write to help you keep track of whether the database object is a the world will explode Or to be a subsequent write query which succeeded on the master may fail when replicated to the slave due to a unique key collision Replication on the slave will stop and it may take hours to repair the database and get it back online Setting read_only in my cnf on the slave will avoid this but given the dire we prefer to have as many checks as possible We provide a but the wrapper functions like please read the documentation for except in special pages derived from QueryPage It s a common pitfall for new developers to submit code containing SQL queries which examine huge numbers of rows Remember that COUNT * is(N), counting rows in atable is like counting beans in a bucket.------------------------------------------------------------------------ Replication------------------------------------------------------------------------The largest installation of MediaWiki, Wikimedia, uses a large set ofslave MySQL servers replicating writes made to a master MySQL server. Itis important to understand the issues associated with this setup if youwant to write code destined for Wikipedia.It 's often the case that the best algorithm to use for a given taskdepends on whether or not replication is in use. Due to our unabashedWikipedia-centrism, we often just use the replication-friendly version, but if you like, you can use wfGetLB() ->getServerCount() > 1 tocheck to see if replication is in use.===Lag===Lag primarily occurs when large write queries are sent to the master.Writes on the master are executed in parallel, but they are executed inserial when they are replicated to the slaves. The master writes thequery to the binlog when the transaction is committed. The slaves pollthe binlog and start executing the query as soon as it appears. They canservice reads while they are performing a write query, but will not readanything more from the binlog and thus will perform no more writes. Thismeans that if the write query runs for a long time, the slaves will lagbehind the master for the time it takes for the write query to complete.Lag can be exacerbated by high read load. MediaWiki 's load balancer willstop sending reads to a slave when it is lagged by more than 30 seconds.If the load ratios are set incorrectly, or if there is too much loadgenerally, this may lead to a slave permanently hovering around 30seconds lag.If all slaves are lagged by more than 30 seconds, MediaWiki will stopwriting to the database. All edits and other write operations will berefused, with an error returned to the user. This gives the slaves achance to catch up. Before we had this mechanism, the slaves wouldregularly lag by several minutes, making review of recent editsdifficult.In addition to this, MediaWiki attempts to ensure that the user seesevents occurring on the wiki in chronological order. A few seconds of lagcan be tolerated, as long as the user sees a consistent picture fromsubsequent requests. This is done by saving the master binlog positionin the session, and then at the start of each request, waiting for theslave to catch up to that position before doing any reads from it. Ifthis wait times out, reads are allowed anyway, but the request isconsidered to be in "lagged slave mode". Lagged slave mode can bechecked by calling wfGetLB() ->getLaggedSlaveMode(). The onlypractical consequence at present is a warning displayed in the pagefooter.===Lag avoidance===To avoid excessive lag, queries which write large numbers of rows shouldbe split up, generally to write one row at a time. Multi-row INSERT ...SELECT queries are the worst offenders should be avoided altogether.Instead do the select first and then the insert.===Working with lag===Despite our best efforts, it 's not practical to guarantee a low-lagenvironment. Lag will usually be less than one second, but mayoccasionally be up to 30 seconds. For scalability, it 's very importantto keep load on the master low, so simply sending all your queries tothe master is not the answer. So when you have a genuine need forup-to-date data, the following approach is advised:1) Do a quick query to the master for a sequence number or timestamp 2) Run the full query on the slave and check if it matches the data you gotfrom the master 3) If it doesn 't, run the full query on the masterTo avoid swamping the master every time the slaves lag, use of thisapproach should be kept to a minimum. In most cases you should just readfrom the slave and let the user deal with the delay.------------------------------------------------------------------------ Lock contention------------------------------------------------------------------------Due to the high write rate on Wikipedia(and some other wikis), MediaWiki developers need to be very careful to structure their writesto avoid long-lasting locks. By default, MediaWiki opens a transactionat the first query, and commits it before the output is sent. Locks willbe held from the time when the query is done until the commit. So youcan reduce lock time by doing as much processing as possible before youdo your write queries.Often this approach is not good enough, and it becomes necessary toenclose small groups of queries in their own transaction. Use thefollowing syntax:$dbw=wfGetDB(DB_MASTER
JobQueueRedis\__construct
__construct(array $params)
Definition: JobQueueRedis.php:92
JobQueueRedis\$server
string $server
Server address.
Definition: JobQueueRedis.php:73
JobQueueRedis\MAX_PUSH_SIZE
const MAX_PUSH_SIZE
Definition: JobQueueRedis.php:77
id
MediaWiki s SiteStore can be cached and stored in a flat in a json format If the SiteStore is frequently the file cache may provide a performance benefit over a database even with memcached in front of it sites are listed in a key value with the key being the site s global id(e.g. "enwiki") and a key-value map as the value. The site list is wrapped with in a "sites" key. Example
Definition: sitescache.txt:17
JobQueueRedis\$compression
string $compression
Compression method to use.
Definition: JobQueueRedis.php:75
MediaWiki\Logger\LoggerFactory\getInstance
static getInstance( $channel)
Get a named logger instance from the currently configured logger factory.
Definition: LoggerFactory.php:92
string
This code would result in ircNotify being run twice when an article is and once for brion Hooks can return three possible true was required This is the default since MediaWiki *some string
Definition: hooks.txt:181
wiki
Prior to maintenance scripts were a hodgepodge of code that had no cohesion or formal method of action Beginning maintenance scripts have been cleaned up to use a unified class Directory structure How to run a script How to write your own DIRECTORY STRUCTURE The maintenance directory of a MediaWiki installation contains several all of which have unique purposes HOW TO RUN A SCRIPT Ridiculously just call php someScript php that s in the top level maintenance directory if not default wiki
Definition: maintenance.txt:27
JobQueueRedis\getAllAcquiredJobs
getAllAcquiredJobs()
Definition: JobQueueRedis.php:551
JobQueueRedis\encodeQueueName
encodeQueueName()
Definition: JobQueueRedis.php:778
JobQueueRedis\doBatchPush
doBatchPush(array $jobs, $flags)
Definition: JobQueueRedis.php:194
JobQueueRedis\doDeduplicateRootJob
doDeduplicateRootJob(IJobSpecification $job)
Definition: JobQueueRedis.php:442
JobQueueRedis\doGetSiblingQueuesWithJobs
doGetSiblingQueuesWithJobs(array $types)
Definition: JobQueueRedis.php:599
$params
$params
Definition: styleTest.css.php:40
JobQueueRedis\getJobFromFields
getJobFromFields(array $fields)
Definition: JobQueueRedis.php:704
wfSplitWikiID
wfSplitWikiID( $wiki)
Split a wiki ID into DB name and table prefix.
Definition: GlobalFunctions.php:2779
$res
$res
Definition: database.txt:21
JobQueueRedis\getAllQueuedJobs
getAllQueuedJobs()
Definition: JobQueueRedis.php:519
JobQueueRedis\doPop
doPop()
Definition: JobQueueRedis.php:313
wfDebugLog
wfDebugLog( $logGroup, $text, $dest='all', array $context=[])
Send a line to a supplementary debug log file, if configured, or main debug log if not.
Definition: GlobalFunctions.php:1087
php
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:37
JobQueueRedis\getJobIterator
getJobIterator(RedisConnRef $conn, array $uids)
Definition: JobQueueRedis.php:583
JobQueueRedis\getJobFromUidInternal
getJobFromUidInternal( $uid, RedisConnRef $conn)
This function should not be called outside JobQueueRedis.
Definition: JobQueueRedis.php:634
UIDGenerator\newRawUUIDv4
static newRawUUIDv4( $flags=0)
Return an RFC4122 compliant v4 UUID.
Definition: UIDGenerator.php:311
Job
Class to both describe a background job and handle jobs.
Definition: Job.php:31
JobQueueRedis\getAllDelayedJobs
getAllDelayedJobs()
Definition: JobQueueRedis.php:535
Job\factory
static factory( $command, Title $title, $params=[])
Create the appropriate object to handle a specific job.
Definition: Job.php:74
JobQueueRedis\getServerQueuesWithJobs
getServerQueuesWithJobs()
Definition: JobQueueRedis.php:662
$blob
$blob
Definition: testCompression.php:65
JobQueue\$type
string $type
Job type.
Definition: JobQueue.php:35
JobQueueRedis\getNewJobFields
getNewJobFields(IJobSpecification $job)
Definition: JobQueueRedis.php:682
$queue
$queue
Definition: mergeMessageFileList.php:160
$title
namespace and then decline to actually register it file or subcat img or subcat $title
Definition: hooks.txt:964
Title\makeTitle
static makeTitle( $ns, $title, $fragment='', $interwiki='')
Create a new Title from a namespace index and a DB key.
Definition: Title.php:534
JobQueueRedis\doGetAbandonedCount
doGetAbandonedCount()
Definition: JobQueueRedis.php:178
JobQueueRedis\optimalOrder
optimalOrder()
Get the default queue order to use if configuration does not specify one.
Definition: JobQueueRedis.php:110
JobQueueError
Definition: JobQueue.php:723
list
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global list
Definition: deferred.txt:11
JobQueueRedis\getCoalesceLocationInternal
getCoalesceLocationInternal()
Do not use this function outside of JobQueue/JobQueueGroup.
Definition: JobQueueRedis.php:595
RedisConnectionPool
Helper class to manage Redis connections.
Definition: RedisConnectionPool.php:40
it
=Architecture==Two class hierarchies are used to provide the functionality associated with the different content models:*Content interface(and AbstractContent base class) define functionality that acts on the concrete content of a page, and *ContentHandler base class provides functionality specific to a content model, but not acting on concrete content. The most important function of ContentHandler is to act as a factory for the appropriate implementation of Content. These Content objects are to be used by MediaWiki everywhere, instead of passing page content around as text. All manipulation and analysis of page content must be done via the appropriate methods of the Content object. For each content model, a subclass of ContentHandler has to be registered with $wgContentHandlers. The ContentHandler object for a given content model can be obtained using ContentHandler::getForModelID($id). Also Title, WikiPage and Revision now have getContentHandler() methods for convenience. ContentHandler objects are singletons that provide functionality specific to the content type, but not directly acting on the content of some page. ContentHandler::makeEmptyContent() and ContentHandler::unserializeContent() can be used to create a Content object of the appropriate type. However, it is recommended to instead use WikiPage::getContent() resp. Revision::getContent() to get a page 's content as a Content object. These two methods should be the ONLY way in which page content is accessed. Another important function of ContentHandler objects is to define custom action handlers for a content model, see ContentHandler::getActionOverrides(). This is similar to what WikiPage::getActionOverrides() was already doing.==Serialization==With the ContentHandler facility, page content no longer has to be text based. Objects implementing the Content interface are used to represent and handle the content internally. For storage and data exchange, each content model supports at least one serialization format via ContentHandler::serializeContent($content). The list of supported formats for a given content model can be accessed using ContentHandler::getSupportedFormats(). Content serialization formats are identified using MIME type like strings. The following formats are built in:*text/x-wiki - wikitext *text/javascript - for js pages *text/css - for css pages *text/plain - for future use, e.g. with plain text messages. *text/html - for future use, e.g. with plain html messages. *application/vnd.php.serialized - for future use with the api and for extensions *application/json - for future use with the api, and for use by extensions *application/xml - for future use with the api, and for use by extensions In PHP, use the corresponding CONTENT_FORMAT_XXX constant. Note that when using the API to access page content, especially action=edit, action=parse and action=query &prop=revisions, the model and format of the content should always be handled explicitly. Without that information, interpretation of the provided content is not reliable. The same applies to XML dumps generated via maintenance/dumpBackup.php or Special:Export. Also note that the API will provide encapsulated, serialized content - so if the API was called with format=json, and contentformat is also json(or rather, application/json), the page content is represented as a string containing an escaped json structure. Extensions that use JSON to serialize some types of page content may provide specialized API modules that allow access to that content in a more natural form.==Compatibility==The ContentHandler facility is introduced in a way that should allow all existing code to keep functioning at least for pages that contain wikitext or other text based content. However, a number of functions and hooks have been deprecated in favor of new versions that are aware of the page 's content model, and will now generate warnings when used. Most importantly, the following functions have been deprecated:*Revisions::getText() is deprecated in favor Revisions::getContent() *WikiPage::getText() is deprecated in favor WikiPage::getContent() Also, the old Article::getContent()(which returns text) is superceded by Article::getContentObject(). However, both methods should be avoided since they do not provide clean access to the page 's actual content. For instance, they may return a system message for non-existing pages. Use WikiPage::getContent() instead. Code that relies on a textual representation of the page content should eventually be rewritten. However, ContentHandler::getContentText() provides a stop-gap that can be used to get text for a page. Its behavior is controlled by $wgContentHandlerTextFallback it
Definition: contenthandler.txt:104
JobQueueRedis\getConnection
getConnection()
Get a connection to the server that handles all sub-queues for this queue.
Definition: JobQueueRedis.php:755
JobQueueRedis\pushBlobs
pushBlobs(RedisConnRef $conn, array $items)
Definition: JobQueueRedis.php:248
RedisConnRef\luaEval
luaEval( $script, array $params, $numKeys)
Definition: RedisConnRef.php:124
JobQueueRedis\supportedOrders
supportedOrders()
Get the allowed queue orders for configuration validation.
Definition: JobQueueRedis.php:106
JobQueueRedis\getQueueKey
getQueueKey( $prop, $type=null)
Definition: JobQueueRedis.php:810
First
The First
Definition: primes.txt:1
and
and(b) You must cause any modified files to carry prominent notices stating that You changed the files
JobQueueRedis\throwRedisException
throwRedisException(RedisConnRef $conn, $e)
Definition: JobQueueRedis.php:770
JobQueueConnectionError
Definition: JobQueue.php:726
JobQueueRedis\doGetDelayedCount
doGetDelayedCount()
Definition: JobQueueRedis.php:164
$args
if( $line===false) $args
Definition: cdb.php:64
JobQueue\getRootJobCacheKey
getRootJobCacheKey( $signature)
Definition: JobQueue.php:528
$name
Allows to change the fields on the form that will be generated $name
Definition: hooks.txt:302
JobQueueRedis\doDelete
doDelete()
Definition: JobQueueRedis.php:494
JobQueueRedis\$logger
LoggerInterface $logger
Definition: JobQueueRedis.php:70
JobQueueRedis\$redisPool
RedisConnectionPool $redisPool
Definition: JobQueueRedis.php:68
release
skin txt MediaWiki includes four core it has been set as the default in MediaWiki since the replacing Monobook it had been the default skin since before being replaced by Vector largely rewritten in while keeping its appearance Several legacy skins were removed in the release
Definition: skin.txt:21
JobQueueRedis\serialize
serialize(array $fields)
Definition: JobQueueRedis.php:717
JobQueueRedis\doGetSize
doGetSize()
Definition: JobQueueRedis.php:132
JobQueueRedis\getGlobalKey
getGlobalKey( $name)
Definition: JobQueueRedis.php:794
are
The ContentHandler facility adds support for arbitrary content types on wiki instead of relying on wikitext for everything It was introduced in MediaWiki Each kind of and so on Built in content types are
Definition: contenthandler.txt:9
JobQueueRedis\doIsEmpty
doIsEmpty()
Definition: JobQueueRedis.php:123
JobQueueRedis\supportsDelayedJobs
supportsDelayedJobs()
Find out if delayed jobs are supported for configuration validation.
Definition: JobQueueRedis.php:114
$job
if(count( $args)< 1) $job
Definition: recompressTracked.php:47
or
or
Definition: APACHE-LICENSE-2.0.txt:114
JobQueueRedis\doIsRootJobOldDuplicate
doIsRootJobOldDuplicate(Job $job)
Definition: JobQueueRedis.php:470
needed
this class mediates it Skin Encapsulates a look and feel for the wiki All of the functions that render HTML and make choices about how to render it are here and are called from various other places when needed(most notably, OutputPage::addWikiText()). The StandardSkin object is a complete implementation
as
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition: distributors.txt:22
JobQueue
Class to handle enqueueing and running of background jobs.
Definition: JobQueue.php:31
RedisConnRef
Helper class to handle automatically marking connectons as reusable (via RAII pattern)
Definition: RedisConnRef.php:31
$keys
$keys
Definition: testCompression.php:67
JobQueueRedis\doAck
doAck(Job $job)
Definition: JobQueueRedis.php:387
in
null for the wiki Added in
Definition: hooks.txt:1591
of
globals txt Globals are evil The original MediaWiki code relied on globals for processing context far too often MediaWiki development since then has been a story of slowly moving context out of global variables and into objects Storing processing context in object member variables allows those objects to be reused in a much more flexible way Consider the elegance of
database rows
Definition: globals.txt:10
JobQueueRedis\unserialize
unserialize( $blob)
Definition: JobQueueRedis.php:736
that
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global then executing the whole list after the page is displayed We don t do anything smart like collating updates to the same table or such because the list is almost always going to have just one item on if that
Definition: deferred.txt:13
JobQueueRedis\doGetSiblingQueueSizes
doGetSiblingQueueSizes(array $types)
Definition: JobQueueRedis.php:603
JobQueueRedis\decodeQueueName
decodeQueueName( $name)
Definition: JobQueueRedis.php:786
JobQueueRedis\popAndAcquireBlob
popAndAcquireBlob(RedisConnRef $conn)
Definition: JobQueueRedis.php:346
JobQueueRedis\getAllAbandonedJobs
getAllAbandonedJobs()
Definition: JobQueueRedis.php:567
then
skin txt MediaWiki includes four core it has been set as the default in MediaWiki since the replacing Monobook it had been the default skin since then
Definition: skin.txt:11
server
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such and we might be restricted by PHP settings such as safe mode or open_basedir We cannot assume that the software even has read access anywhere useful Many shared hosts run all users web applications under the same so they can t rely on Unix and must forbid reads to even standard directories like tmp lest users read each others files We cannot assume that the user has the ability to install or run any programs not written as web accessible PHP scripts Since anything that works on cheap shared hosting will work if you have shell or root access MediaWiki s design is based around catering to the lowest common denominator Although we support higher end setups as the way many things work by default is tailored toward shared hosting These defaults are unconventional from the point of view of and they certainly aren t ideal for someone who s installing MediaWiki as MediaWiki does not conform to normal Unix filesystem layout Hopefully we ll offer direct support for standard layouts in the but for now *any change to the location of files is unsupported *Moving things and leaving symlinks will *probably *not break but it is *strongly *advised not to try any more intrusive changes to get MediaWiki to conform more closely to your filesystem hierarchy Any such attempt will almost certainly result in unnecessary bugs The standard recommended location to install relative to the web is it should be possible to enable the appropriate rewrite rules by if you can reconfigure the web server
Definition: distributors.txt:54
false
processing should stop and the error should be shown to the user * false
Definition: hooks.txt:187
IJobSpecification
Job queue task description interface.
Definition: JobSpecification.php:29
JobQueueRedis
Class to handle job queues stored in Redis.
Definition: JobQueueRedis.php:66
$e
div flags Integer display flags(NO_ACTION_LINK, NO_EXTRA_USER_LINKS) 'LogException' returning false will NOT prevent logging $e
Definition: hooks.txt:2171
data
and how to run hooks for an and one after Each event has a preferably in CamelCase For ArticleDelete hook A clump of code and data that should be run when an event happens This can be either a function and a chunk of data
Definition: hooks.txt:18