28 require __DIR__ .
'/../commandLine.inc';
30 if ( count(
$args ) < 1 ) {
31 echo
"Usage: php recompressTracked.php [options] <cluster> [... <cluster>...]
32 Moves blobs indexed by trackBlobs.php to a specified list of destination clusters,
33 and recompresses them in the process. Restartable.
36 --procs <procs> Set the number of child processes (default 1)
37 --copy-only Copy only, do not update the text table. Restart
38 without this option to complete.
39 --debug-log <file> Log debugging data to the specified file
40 --info-log <file> Log progress messages to the specified file
41 --critical-log <file> Log error messages to the specified file
80 'no-count' =>
'noCount',
81 'procs' =>
'numProcs',
82 'copy-only' =>
'copyOnly',
84 'slave-id' =>
'slaveId',
85 'debug-log' =>
'debugLog',
86 'info-log' =>
'infoLog',
87 'critical-log' =>
'criticalLog',
95 $jobOptions = [
'destClusters' =>
$args ];
96 foreach ( self::$cmdLineOptionMap
as $cmdOption => $classOption ) {
97 if ( isset(
$options[$cmdOption] ) ) {
98 $jobOptions[$classOption] =
$options[$cmdOption];
102 return new self( $jobOptions );
110 if ( !$this->isChild ) {
111 $GLOBALS[
'wgDebugLogPrefix'] =
"RCT M: ";
112 } elseif ( $this->slaveId !==
false ) {
113 $GLOBALS[
'wgDebugLogPrefix'] =
"RCT {$this->slaveId}: ";
115 $this->useDiff = function_exists(
'xdiff_string_bdiff' );
116 $this->pageBlobClass = $this->useDiff ?
'DiffHistoryBlob' :
'ConcatenatedGzipHistoryBlob';
117 $this->orphanBlobClass =
'ConcatenatedGzipHistoryBlob';
122 if ( $this->debugLog ) {
123 $this->
logToFile( $msg, $this->debugLog );
129 if ( $this->infoLog ) {
130 $this->
logToFile( $msg, $this->infoLog );
136 if ( $this->criticalLog ) {
137 $this->
logToFile( $msg, $this->criticalLog );
142 $header =
'[' . date(
'd\TH:i:s' ) .
'] ' .
wfHostname() .
' ' . posix_getpid();
143 if ( $this->slaveId !==
false ) {
144 $header .=
"({$this->slaveId})";
147 LegacyLogger::emit( sprintf(
"%-50s %s\n", $header, $msg ), $file );
158 $pos = $dbw->getMasterPos();
159 $dbr->masterPosWait( $pos, 100000 );
166 if ( $this->isChild ) {
194 if ( !
$dbr->tableExists(
'blob_tracking' ) ) {
195 $this->
critical(
"Error: blob_tracking table does not exist" );
199 $row =
$dbr->selectRow(
'blob_tracking',
'*',
'', __METHOD__ );
201 $this->
info(
"Warning: blob_tracking table contains no rows, skipping this wiki." );
217 foreach ( self::$cmdLineOptionMap
as $cmdOption => $classOption ) {
218 if ( $cmdOption ==
'slave-id' ) {
222 } elseif ( $this->$classOption ) {
223 $cmd .=
" --$cmdOption";
228 ' ' . call_user_func_array(
'wfEscapeShellArg', $this->destClusters );
230 $this->slavePipes = $this->slaveProcs = [];
235 [
'file',
'php://stdout',
'w' ],
236 [
'file',
'php://stderr',
'w' ]
238 MediaWiki\suppressWarnings();
239 $proc = proc_open(
"$cmd --slave-id $i", $spec, $pipes );
240 MediaWiki\restoreWarnings();
242 $this->
critical(
"Error opening slave process: $cmd" );
245 $this->slaveProcs[$i] = $proc;
246 $this->slavePipes[$i] = $pipes[0];
248 $this->prevSlaveId = -1;
255 $this->
info(
"Waiting for slave processes to finish..." );
260 $status = proc_close( $this->slaveProcs[$i] );
262 $this->
critical(
"Warning: child #$i exited with status $status" );
265 $this->
info(
"Done." );
273 $args = func_get_args();
275 $numPipes = stream_select( $x = [], $pipes, $y = [], 3600 );
277 $this->
critical(
"Error waiting to write to slaves. Aborting" );
281 $slaveId = ( $i + $this->prevSlaveId + 1 ) % $this->numProcs;
300 $cmd = implode(
' ',
$args );
301 fwrite( $this->slavePipes[
$slaveId],
"$cmd\n" );
311 if ( $this->noCount ) {
312 $numPages =
'[unknown]';
314 $numPages =
$dbr->selectField(
'blob_tracking',
315 'COUNT(DISTINCT bt_page)',
321 if ( $this->copyOnly ) {
322 $this->
info(
"Copying pages..." );
324 $this->
info(
"Moving pages..." );
327 $res =
$dbr->select(
'blob_tracking',
331 'bt_page > ' .
$dbr->addQuotes( $startId )
336 'ORDER BY' =>
'bt_page',
340 if ( !
$res->numRows() ) {
343 foreach (
$res as $row ) {
344 $startId = $row->bt_page;
345 $this->
dispatch(
'doPage', $row->bt_page );
348 $this->
report(
'pages', $i, $numPages );
350 $this->
report(
'pages', $i, $numPages );
351 if ( $this->copyOnly ) {
352 $this->
info(
"All page copies queued." );
354 $this->
info(
"All page moves queued." );
364 function report( $label, $current, $end ) {
366 if ( $current == $end || $this->numBatches >= $this->reportingInterval ) {
367 $this->numBatches = 0;
368 $this->
info(
"$label: $current / $end" );
380 if ( $this->noCount ) {
381 $numOrphans =
'[unknown]';
383 $numOrphans =
$dbr->selectField(
'blob_tracking',
384 'COUNT(DISTINCT bt_text_id)',
385 [
'bt_moved' => 0,
'bt_page' => 0 ],
387 if ( !$numOrphans ) {
391 if ( $this->copyOnly ) {
392 $this->
info(
"Copying orphans..." );
394 $this->
info(
"Moving orphans..." );
398 $res =
$dbr->select(
'blob_tracking',
403 'bt_text_id > ' .
$dbr->addQuotes( $startId )
408 'ORDER BY' =>
'bt_text_id',
412 if ( !
$res->numRows() ) {
416 foreach (
$res as $row ) {
417 $startId = $row->bt_text_id;
418 $ids[] = $row->bt_text_id;
425 $args = array_slice( $ids, 0, $this->orphanBatchSize );
426 $ids = array_slice( $ids, $this->orphanBatchSize );
427 array_unshift(
$args,
'doOrphanList' );
428 call_user_func_array( [ $this,
'dispatch' ],
$args );
430 if ( count( $ids ) ) {
432 array_unshift(
$args,
'doOrphanList' );
433 call_user_func_array( [ $this,
'dispatch' ],
$args );
436 $this->
report(
'orphans', $i, $numOrphans );
438 $this->
report(
'orphans', $i, $numOrphans );
439 $this->
info(
"All orphans queued." );
446 $this->
debug(
'starting' );
449 while ( !feof( STDIN ) ) {
450 $line = rtrim( fgets( STDIN ) );
456 $cmd = array_shift(
$args );
479 $titleText =
$title->getPrefixedText();
481 $titleText =
'[deleted]';
486 if ( !$this->copyOnly ) {
496 [
'blob_tracking',
'text' ],
499 'bt_page' => $pageId,
500 'bt_text_id > ' .
$dbr->addQuotes( $startId ),
502 'bt_new_url IS NULL',
507 'ORDER BY' =>
'bt_text_id',
511 if ( !
$res->numRows() ) {
516 foreach (
$res as $row ) {
517 $startId = $row->bt_text_id;
518 if ( $lastTextId == $row->bt_text_id ) {
522 $lastTextId = $row->bt_text_id;
525 if ( $text ===
false ) {
526 $this->
critical(
"Error loading {$row->bt_rev_id}/{$row->bt_text_id}" );
531 if ( !$trx->addItem( $text, $row->bt_text_id ) ) {
532 $this->
debug(
"$titleText: committing blob with " . $trx->getSize() .
" items" );
540 $this->
debug(
"$titleText: committing blob with " . $trx->getSize() .
" items" );
558 if ( $this->copyOnly ) {
559 $this->
critical(
"Internal error: can't call moveTextRow() in --copy-only mode" );
563 $dbw->begin( __METHOD__ );
564 $dbw->update(
'text',
567 'old_flags' =>
'external,utf-8',
574 $dbw->update(
'blob_tracking',
576 [
'bt_text_id' => $textId ],
579 $dbw->commit( __METHOD__ );
596 $conds = array_merge( $conds, [
598 'bt_new_url IS NOT NULL'
601 $res =
$dbr->select(
'blob_tracking',
603 array_merge( $conds, [
'bt_text_id > ' .
$dbr->addQuotes( $startId ) ] ),
606 'ORDER BY' =>
'bt_text_id',
607 'LIMIT' => $this->batchSize,
610 if ( !
$res->numRows() ) {
613 $this->
debug(
'Incomplete: ' .
$res->numRows() .
' rows' );
614 foreach (
$res as $row ) {
615 $startId = $row->bt_text_id;
616 $this->
moveTextRow( $row->bt_text_id, $row->bt_new_url );
617 if ( $row->bt_text_id % 10 == 0 ) {
629 $cluster = next( $this->destClusters );
630 if ( $cluster ===
false ) {
631 $cluster = reset( $this->destClusters );
655 if ( !$this->copyOnly ) {
663 [
'text',
'blob_tracking' ],
664 [
'old_id',
'old_text',
'old_flags' ],
666 'old_id' => $textIds,
674 foreach (
$res as $row ) {
676 if ( $text ===
false ) {
677 $this->
critical(
"Error: cannot load revision text for old_id={$row->old_id}" );
681 if ( !$trx->addItem( $text, $row->old_id ) ) {
682 $this->
debug(
"[orphan]: committing blob with " . $trx->getSize() .
" rows" );
688 $this->
debug(
"[orphan]: committing blob with " . $trx->getSize() .
" rows" );
726 $this->cgz =
new $class;
728 $hash = $this->cgz->addItem( $text );
729 $this->referrers[$textId] = $hash;
730 $this->texts[$textId] = $text;
732 return $this->cgz->isHappy();
736 return count( $this->texts );
744 $this->cgz =
new $class;
745 $this->referrers = [];
746 foreach ( $this->texts
as $textId => $text ) {
747 $hash = $this->cgz->addItem( $text );
748 $this->referrers[$textId] = $hash;
758 $originalCount = count( $this->texts );
759 if ( !$originalCount ) {
772 $dbw->begin( __METHOD__ );
773 $res = $dbw->select(
'blob_tracking',
774 [
'bt_text_id',
'bt_moved' ],
775 [
'bt_text_id' => array_keys( $this->referrers ) ],
776 __METHOD__, [
'FOR UPDATE' ] );
778 foreach (
$res as $row ) {
779 if ( $row->bt_moved ) {
780 # This row has already been moved, remove it
781 $this->parent->debug(
"TRX: conflict detected in old_id={$row->bt_text_id}" );
782 unset( $this->texts[$row->bt_text_id] );
789 if ( !count( $this->texts ) ) {
791 if ( $originalCount > 1 ) {
793 $this->parent->critical(
794 "Warning: concurrent operation detected, are there two conflicting " .
795 "processes running, doing the same job?" );
804 $targetCluster = $this->parent->getTargetCluster();
805 $store = $this->parent->store;
806 $targetDB = $store->getMaster( $targetCluster );
807 $targetDB->clearFlag(
DBO_TRX );
808 $targetDB->begin( __METHOD__ );
809 $baseUrl = $this->parent->store->store( $targetCluster,
serialize( $this->cgz ) );
812 foreach ( $this->referrers
as $textId => $hash ) {
813 $url = $baseUrl .
'/' . $hash;
814 $dbw->update(
'blob_tracking',
815 [
'bt_new_url' => $url ],
817 'bt_text_id' => $textId,
818 'bt_moved' => 0, # Check
for concurrent conflicting update
824 $targetDB->commit( __METHOD__ );
827 $dbw->commit( __METHOD__ );
830 if ( !$this->parent->copyOnly ) {
831 foreach ( $this->referrers
as $textId => $hash ) {
832 $url = $baseUrl .
'/' . $hash;
833 $this->parent->moveTextRow( $textId, $url );
killSlaveProcs()
Gracefully terminate the child processes.
#define the
table suitable for use with IDatabase::select()
static newFromID($id, $flags=0)
Create a new Title from an article ID.
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global then executing the whole list after the page is displayed We don t do anything smart like collating updates to the same table or such because the list is almost always going to have just one item on if that
MediaWiki Logger LegacyLogger
wfGetDB($db, $groups=[], $wiki=false)
Get a Database object.
the array() calling protocol came about after MediaWiki 1.4rc1.
static getRevisionText($row, $prefix= 'old_', $wiki=false)
Get revision text associated with an old or archive row $row is usually an object from wfFetchRow()...
wfWaitForSlaves($ifWritesSince=null, $wiki=false, $cluster=false, $timeout=null)
Waits for the slaves to catch up to the master position.
dispatchToSlave($slaveId, $args)
Dispatch a command to a specified slave.
dispatch()
Dispatch a command to the next available slave.
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
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
wfHostname()
Fetch server name for use in error reporting etc.
addItem($text, $textId)
Add text.
getTargetCluster()
Returns the name of the next target cluster.
RecompressTracked $parent
finishIncompleteMoves($conds)
Moves are done in two phases: bt_new_url and then bt_moved.
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 store
wfDebug($text, $dest= 'all', array $context=[])
Sends a line to the debug log if enabled or, optionally, to a comment in output.
executeParent()
Execute the parent process.
ConcatenatedGzipHistoryBlob $cgz
doAllOrphans()
Move all orphan text to the new clusters.
this hook is for auditing only RecentChangesLinked and Watchlist RecentChangesLinked and Watchlist e g Watchlist removed from all revisions and log entries to which it was applied This gives extensions a chance to take it off their books as the deletion has already been partly carried out by this point or something similar the user will be unable to create the tag set and then return false from the hook function Ensure you consume the ChangeTagAfterDelete hook to carry out custom deletion actions as context called by AbstractContent::getParserOutput May be used to override the normal model specific rendering of page content as context as context $options
doPage($pageId)
Move tracked text in a given page.
getExtDB($cluster)
Gets a DB master connection for the given external cluster name.
static newFromCommandLine($args, $options)
namespace and then decline to actually register it file or subcat img or subcat $title
Maintenance script that moves blobs indexed by trackBlobs.php to a specified list of destination clus...
executeChild()
Main entry point for worker processes.
wfWikiID()
Get an ASCII string identifying this wiki This is used as a prefix in memcached keys.
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Class to represent a recompression operation for a single CGZ blob.
checkTrackingTable()
Make sure the tracking table exists and isn't empty.
report($label, $current, $end)
Display a progress report.
__construct($parent, $blobClass)
Create a transaction from a RecompressTracked object.
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
wfGetLBFactory()
Get the load balancer factory object.
doAllPages()
Move all tracked pages to the new clusters.
startSlaveProcs()
Start the worker processes.
recompress()
Recompress text after some aberrant modification.
static static getOptionsWithArgs()
this hook is for auditing only RecentChangesLinked and Watchlist RecentChangesLinked and Watchlist e g Watchlist removed from all revisions and log entries to which it was applied This gives extensions a chance to take it off their books as the deletion has already been partly carried out by this point or something similar the user will be unable to create the tag set $status
wfEscapeShellArg()
Windows-compatible version of escapeshellarg() Windows doesn't recognise single-quotes in the shell...
execute()
Execute parent or child depending on the isChild option.
DB accessable external objects.
doOrphanList($textIds)
Move an orphan text_id to the new cluster.
syncDBs()
Wait until the selected slave has caught up to the master.
moveTextRow($textId, $url)
Atomic move operation.
Allows to change the fields on the form that will be generated $name