3 * Moves blobs indexed by trackBlobs.php to a specified list of destination
4 * clusters, and recompresses them in the process.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License along
17 * with this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
19 * http://www.gnu.org/copyleft/gpl.html
22 * @ingroup Maintenance ExternalStorage
25 use MediaWiki\Storage\SqlBlobStore
;
26 use Wikimedia\Rdbms\IMaintainableDatabase
;
27 use MediaWiki\Logger\LegacyLogger
;
28 use MediaWiki\MediaWikiServices
;
29 use MediaWiki\Shell\Shell
;
31 $optionsWithArgs = RecompressTracked
::getOptionsWithArgs();
32 require __DIR__
. '/../commandLine.inc';
34 if ( count( $args ) < 1 ) {
35 echo "Usage: php recompressTracked.php [options] <cluster> [... <cluster>...]
36 Moves blobs indexed by trackBlobs.php to a specified list of destination clusters,
37 and recompresses them in the process. Restartable.
40 --procs <procs> Set the number of child processes (default 1)
41 --copy-only Copy only, do not update the text table. Restart
42 without this option to complete.
43 --debug-log <file> Log debugging data to the specified file
44 --info-log <file> Log progress messages to the specified file
45 --critical-log <file> Log error messages to the specified file
50 $job = RecompressTracked
::newFromCommandLine( $args, $options );
54 * Maintenance script that moves blobs indexed by trackBlobs.php to a specified
55 * list of destination clusters, and recompresses them in the process.
57 * @ingroup Maintenance ExternalStorage
59 class RecompressTracked
{
61 public $batchSize = 1000;
62 public $orphanBatchSize = 1000;
63 public $reportingInterval = 10;
65 public $numBatches = 0;
66 public $pageBlobClass, $orphanBlobClass;
67 public $childPipes, $childProcs, $prevChildId;
68 public $copyOnly = false;
69 public $isChild = false;
70 public $childId = false;
71 public $noCount = false;
72 public $debugLog, $infoLog, $criticalLog;
73 /** @var ExternalStoreDB */
75 /** @var SqlBlobStore */
78 private static $optionsWithArgs = [
86 private static $cmdLineOptionMap = [
87 'no-count' => 'noCount',
88 'procs' => 'numProcs',
89 'copy-only' => 'copyOnly',
91 'child-id' => 'childId',
92 'debug-log' => 'debugLog',
93 'info-log' => 'infoLog',
94 'critical-log' => 'criticalLog',
97 static function getOptionsWithArgs() {
98 return self
::$optionsWithArgs;
101 static function newFromCommandLine( $args, $options ) {
102 $jobOptions = [ 'destClusters' => $args ];
103 foreach ( self
::$cmdLineOptionMap as $cmdOption => $classOption ) {
104 if ( isset( $options[$cmdOption] ) ) {
105 $jobOptions[$classOption] = $options[$cmdOption];
109 return new self( $jobOptions );
112 function __construct( $options ) {
113 foreach ( $options as $name => $value ) {
114 $this->$name = $value;
116 $esFactory = MediaWikiServices
::getInstance()->getExternalStoreFactory();
117 $this->store
= $esFactory->getStore( 'DB' );
118 if ( !$this->isChild
) {
119 $GLOBALS['wgDebugLogPrefix'] = "RCT M: ";
120 } elseif ( $this->childId
!== false ) {
121 $GLOBALS['wgDebugLogPrefix'] = "RCT {$this->childId}: ";
123 $this->pageBlobClass
= function_exists( 'xdiff_string_bdiff' ) ?
124 DiffHistoryBlob
::class : ConcatenatedGzipHistoryBlob
::class;
125 $this->orphanBlobClass
= ConcatenatedGzipHistoryBlob
::class;
126 // @phan-suppress-next-line PhanAccessMethodInternal
127 $this->blobStore
= MediaWikiServices
::getInstance()
128 ->getBlobStoreFactory()
132 function debug( $msg ) {
134 if ( $this->debugLog
) {
135 $this->logToFile( $msg, $this->debugLog
);
139 function info( $msg ) {
141 if ( $this->infoLog
) {
142 $this->logToFile( $msg, $this->infoLog
);
146 function critical( $msg ) {
148 if ( $this->criticalLog
) {
149 $this->logToFile( $msg, $this->criticalLog
);
153 function logToFile( $msg, $file ) {
154 $header = '[' . date( 'd\TH:i:s' ) . '] ' . wfHostname() . ' ' . posix_getpid();
155 if ( $this->childId
!== false ) {
156 $header .= "({$this->childId})";
158 $header .= ' ' . WikiMap
::getCurrentWikiDbDomain()->getId();
159 LegacyLogger
::emit( sprintf( "%-50s %s\n", $header, $msg ), $file );
163 * Wait until the selected replica DB has caught up to the master.
164 * This allows us to use the replica DB for things that were committed in a
165 * previous part of this batch process.
168 $dbw = wfGetDB( DB_MASTER
);
169 $dbr = wfGetDB( DB_REPLICA
);
170 $pos = $dbw->getMasterPos();
171 $dbr->masterPosWait( $pos, 100000 );
175 * Execute parent or child depending on the isChild option
178 if ( $this->isChild
) {
179 $this->executeChild();
181 $this->executeParent();
186 * Execute the parent process
188 function executeParent() {
189 if ( !$this->checkTrackingTable() ) {
194 $this->startChildProcs();
196 $this->doAllOrphans();
197 $this->killChildProcs();
201 * Make sure the tracking table exists and isn't empty
204 function checkTrackingTable() {
205 $dbr = wfGetDB( DB_REPLICA
);
206 if ( !$dbr->tableExists( 'blob_tracking' ) ) {
207 $this->critical( "Error: blob_tracking table does not exist" );
211 $row = $dbr->selectRow( 'blob_tracking', '*', '', __METHOD__
);
213 $this->info( "Warning: blob_tracking table contains no rows, skipping this wiki." );
222 * Start the worker processes.
223 * These processes will listen on stdin for commands.
224 * This necessary because text recompression is slow: loading, compressing and
225 * writing are all slow.
227 function startChildProcs() {
228 $wiki = WikiMap
::getWikiIdFromDbDomain( WikiMap
::getCurrentWikiDbDomain() );
230 $cmd = 'php ' . Shell
::escape( __FILE__
);
231 foreach ( self
::$cmdLineOptionMap as $cmdOption => $classOption ) {
232 if ( $cmdOption == 'child-id' ) {
234 } elseif ( in_array( $cmdOption, self
::$optionsWithArgs ) && isset( $this->$classOption ) ) {
235 $cmd .= " --$cmdOption " . Shell
::escape( $this->$classOption );
236 } elseif ( $this->$classOption ) {
237 $cmd .= " --$cmdOption";
241 ' --wiki ' . Shell
::escape( $wiki ) .
242 ' ' . Shell
::escape( ...$this->destClusters
);
244 $this->childPipes
= $this->childProcs
= [];
245 for ( $i = 0; $i < $this->numProcs
; $i++
) {
249 [ 'file', 'php://stdout', 'w' ],
250 [ 'file', 'php://stderr', 'w' ]
252 Wikimedia\
suppressWarnings();
253 $proc = proc_open( "$cmd --child-id $i", $spec, $pipes );
254 Wikimedia\restoreWarnings
();
256 $this->critical( "Error opening child process: $cmd" );
259 $this->childProcs
[$i] = $proc;
260 $this->childPipes
[$i] = $pipes[0];
262 $this->prevChildId
= -1;
266 * Gracefully terminate the child processes
268 function killChildProcs() {
269 $this->info( "Waiting for child processes to finish..." );
270 for ( $i = 0; $i < $this->numProcs
; $i++
) {
271 $this->dispatchToChild( $i, 'quit' );
273 for ( $i = 0; $i < $this->numProcs
; $i++
) {
274 $status = proc_close( $this->childProcs
[$i] );
276 $this->critical( "Warning: child #$i exited with status $status" );
279 $this->info( "Done." );
283 * Dispatch a command to the next available child process.
284 * This may block until a child process finishes its work and becomes available.
285 * @param array|string ...$args
287 function dispatch( ...$args ) {
288 $pipes = $this->childPipes
;
291 $numPipes = stream_select( $x, $pipes, $y, 3600 );
293 $this->critical( "Error waiting to write to child process. Aborting" );
296 for ( $i = 0; $i < $this->numProcs
; $i++
) {
297 $childId = ( $i +
$this->prevChildId +
1 ) %
$this->numProcs
;
298 if ( isset( $pipes[$childId] ) ) {
299 $this->prevChildId
= $childId;
300 $this->dispatchToChild( $childId, $args );
305 $this->critical( "Unreachable" );
310 * Dispatch a command to a specified child process
311 * @param int $childId
312 * @param array|string $args
314 function dispatchToChild( $childId, $args ) {
315 $args = (array)$args;
316 $cmd = implode( ' ', $args );
317 fwrite( $this->childPipes
[$childId], "$cmd\n" );
321 * Move all tracked pages to the new clusters
323 function doAllPages() {
324 $dbr = wfGetDB( DB_REPLICA
);
327 if ( $this->noCount
) {
328 $numPages = '[unknown]';
330 $numPages = $dbr->selectField( 'blob_tracking',
331 'COUNT(DISTINCT bt_page)',
332 # A condition is required so that this query uses the index
337 if ( $this->copyOnly
) {
338 $this->info( "Copying pages..." );
340 $this->info( "Moving pages..." );
343 $res = $dbr->select( 'blob_tracking',
347 'bt_page > ' . $dbr->addQuotes( $startId )
352 'ORDER BY' => 'bt_page',
353 'LIMIT' => $this->batchSize
,
356 if ( !$res->numRows() ) {
359 foreach ( $res as $row ) {
360 $startId = $row->bt_page
;
361 $this->dispatch( 'doPage', $row->bt_page
);
364 $this->report( 'pages', $i, $numPages );
366 $this->report( 'pages', $i, $numPages );
367 if ( $this->copyOnly
) {
368 $this->info( "All page copies queued." );
370 $this->info( "All page moves queued." );
375 * Display a progress report
376 * @param string $label
377 * @param int $current
380 function report( $label, $current, $end ) {
382 if ( $current == $end ||
$this->numBatches
>= $this->reportingInterval
) {
383 $this->numBatches
= 0;
384 $this->info( "$label: $current / $end" );
385 MediaWikiServices
::getInstance()->getDBLoadBalancerFactory()->waitForReplication();
390 * Move all orphan text to the new clusters
392 function doAllOrphans() {
393 $dbr = wfGetDB( DB_REPLICA
);
396 if ( $this->noCount
) {
397 $numOrphans = '[unknown]';
399 $numOrphans = $dbr->selectField( 'blob_tracking',
400 'COUNT(DISTINCT bt_text_id)',
401 [ 'bt_moved' => 0, 'bt_page' => 0 ],
403 if ( !$numOrphans ) {
407 if ( $this->copyOnly
) {
408 $this->info( "Copying orphans..." );
410 $this->info( "Moving orphans..." );
414 $res = $dbr->select( 'blob_tracking',
419 'bt_text_id > ' . $dbr->addQuotes( $startId )
424 'ORDER BY' => 'bt_text_id',
425 'LIMIT' => $this->batchSize
428 if ( !$res->numRows() ) {
432 foreach ( $res as $row ) {
433 $startId = $row->bt_text_id
;
434 $ids[] = $row->bt_text_id
;
437 // Need to send enough orphan IDs to the child at a time to fill a blob,
438 // so orphanBatchSize needs to be at least ~100.
439 // batchSize can be smaller or larger.
440 while ( count( $ids ) > $this->orphanBatchSize
) {
441 $args = array_slice( $ids, 0, $this->orphanBatchSize
);
442 $ids = array_slice( $ids, $this->orphanBatchSize
);
443 array_unshift( $args, 'doOrphanList' );
444 $this->dispatch( ...$args );
446 if ( count( $ids ) ) {
448 array_unshift( $args, 'doOrphanList' );
449 $this->dispatch( ...$args );
452 $this->report( 'orphans', $i, $numOrphans );
454 $this->report( 'orphans', $i, $numOrphans );
455 $this->info( "All orphans queued." );
459 * Main entry point for worker processes
461 function executeChild() {
462 $this->debug( 'starting' );
465 while ( !feof( STDIN
) ) {
466 $line = rtrim( fgets( STDIN
) );
470 $this->debug( $line );
471 $args = explode( ' ', $line );
472 $cmd = array_shift( $args );
475 $this->doPage( intval( $args[0] ) );
478 $this->doOrphanList( array_map( 'intval', $args ) );
483 MediaWikiServices
::getInstance()->getDBLoadBalancerFactory()->waitForReplication();
488 * Move tracked text in a given page
492 function doPage( $pageId ) {
493 $title = Title
::newFromID( $pageId );
495 $titleText = $title->getPrefixedText();
497 $titleText = '[deleted]';
499 $dbr = wfGetDB( DB_REPLICA
);
501 // Finish any incomplete transactions
502 if ( !$this->copyOnly
) {
503 $this->finishIncompleteMoves( [ 'bt_page' => $pageId ] );
508 $trx = new CgzCopyTransaction( $this, $this->pageBlobClass
);
510 $lbFactory = MediaWikiServices
::getInstance()->getDBLoadBalancerFactory();
513 [ 'blob_tracking', 'text' ],
516 'bt_page' => $pageId,
517 'bt_text_id > ' . $dbr->addQuotes( $startId ),
519 'bt_new_url IS NULL',
524 'ORDER BY' => 'bt_text_id',
525 'LIMIT' => $this->batchSize
528 if ( !$res->numRows() ) {
533 foreach ( $res as $row ) {
534 $startId = $row->bt_text_id
;
535 if ( $lastTextId == $row->bt_text_id
) {
536 // Duplicate (null edit)
539 $lastTextId = $row->bt_text_id
;
541 $text = $this->blobStore
->expandBlob( $row->old_text
, $row->old_flags
);
542 if ( $text === false ) {
543 $this->critical( "Error loading {$row->bt_rev_id}/{$row->bt_text_id}" );
548 if ( !$trx->addItem( $text, $row->bt_text_id
) ) {
549 $this->debug( "$titleText: committing blob with " . $trx->getSize() . " items" );
551 $trx = new CgzCopyTransaction( $this, $this->pageBlobClass
);
552 $lbFactory->waitForReplication();
557 $this->debug( "$titleText: committing blob with " . $trx->getSize() . " items" );
562 * Atomic move operation.
564 * Write the new URL to the text table and set the bt_moved flag.
566 * This is done in a single transaction to provide restartable behavior
569 * The transaction is kept short to reduce locking.
574 function moveTextRow( $textId, $url ) {
575 if ( $this->copyOnly
) {
576 $this->critical( "Internal error: can't call moveTextRow() in --copy-only mode" );
579 $dbw = wfGetDB( DB_MASTER
);
580 $dbw->begin( __METHOD__
);
581 $dbw->update( 'text',
584 'old_flags' => 'external,utf-8',
591 $dbw->update( 'blob_tracking',
593 [ 'bt_text_id' => $textId ],
596 $dbw->commit( __METHOD__
);
600 * Moves are done in two phases: bt_new_url and then bt_moved.
601 * - bt_new_url indicates that the text has been copied to the new cluster.
602 * - bt_moved indicates that the text table has been updated.
604 * This function completes any moves that only have done bt_new_url. This
605 * can happen when the script is interrupted, or when --copy-only is used.
607 * @param array $conds
609 function finishIncompleteMoves( $conds ) {
610 $dbr = wfGetDB( DB_REPLICA
);
611 $lbFactory = MediaWikiServices
::getInstance()->getDBLoadBalancerFactory();
614 $conds = array_merge( $conds, [
616 'bt_new_url IS NOT NULL'
619 $res = $dbr->select( 'blob_tracking',
621 array_merge( $conds, [ 'bt_text_id > ' . $dbr->addQuotes( $startId ) ] ),
624 'ORDER BY' => 'bt_text_id',
625 'LIMIT' => $this->batchSize
,
628 if ( !$res->numRows() ) {
631 $this->debug( 'Incomplete: ' . $res->numRows() . ' rows' );
632 foreach ( $res as $row ) {
633 $startId = $row->bt_text_id
;
634 $this->moveTextRow( $row->bt_text_id
, $row->bt_new_url
);
635 if ( $row->bt_text_id %
10 == 0 ) {
636 $lbFactory->waitForReplication();
643 * Returns the name of the next target cluster
646 function getTargetCluster() {
647 $cluster = next( $this->destClusters
);
648 if ( $cluster === false ) {
649 $cluster = reset( $this->destClusters
);
656 * Gets a DB master connection for the given external cluster name
657 * @param string $cluster
658 * @return IMaintainableDatabase
660 function getExtDB( $cluster ) {
661 $lbFactory = MediaWikiServices
::getInstance()->getDBLoadBalancerFactory();
662 $lb = $lbFactory->getExternalLB( $cluster );
664 return $lb->getMaintenanceConnectionRef( DB_MASTER
);
668 * Move an orphan text_id to the new cluster
670 * @param array $textIds
672 function doOrphanList( $textIds ) {
673 // Finish incomplete moves
674 if ( !$this->copyOnly
) {
675 $this->finishIncompleteMoves( [ 'bt_text_id' => $textIds ] );
679 $trx = new CgzCopyTransaction( $this, $this->orphanBlobClass
);
681 $lbFactory = MediaWikiServices
::getInstance()->getDBLoadBalancerFactory();
682 $res = wfGetDB( DB_REPLICA
)->select(
683 [ 'text', 'blob_tracking' ],
684 [ 'old_id', 'old_text', 'old_flags' ],
686 'old_id' => $textIds,
694 foreach ( $res as $row ) {
695 $text = $this->blobStore
->expandBlob( $row->old_text
, $row->old_flags
);
696 if ( $text === false ) {
697 $this->critical( "Error: cannot load revision text for old_id={$row->old_id}" );
701 if ( !$trx->addItem( $text, $row->old_id
) ) {
702 $this->debug( "[orphan]: committing blob with " . $trx->getSize() . " rows" );
704 $trx = new CgzCopyTransaction( $this, $this->orphanBlobClass
);
705 $lbFactory->waitForReplication();
708 $this->debug( "[orphan]: committing blob with " . $trx->getSize() . " rows" );
714 * Class to represent a recompression operation for a single CGZ blob
716 class CgzCopyTransaction
{
717 /** @var RecompressTracked */
720 /** @var ConcatenatedGzipHistoryBlob|false */
727 * Create a transaction from a RecompressTracked object
728 * @param RecompressTracked $parent
729 * @param string $blobClass
731 function __construct( $parent, $blobClass ) {
732 $this->blobClass
= $blobClass;
735 $this->parent
= $parent;
740 * Returns false if it's ready to commit.
741 * @param string $text
745 function addItem( $text, $textId ) {
747 $class = $this->blobClass
;
748 $this->cgz
= new $class;
750 $hash = $this->cgz
->addItem( $text );
751 $this->referrers
[$textId] = $hash;
752 $this->texts
[$textId] = $text;
754 return $this->cgz
->isHappy();
758 return count( $this->texts
);
762 * Recompress text after some aberrant modification
764 function recompress() {
765 $class = $this->blobClass
;
766 $this->cgz
= new $class;
767 $this->referrers
= [];
768 foreach ( $this->texts
as $textId => $text ) {
769 $hash = $this->cgz
->addItem( $text );
770 $this->referrers
[$textId] = $hash;
776 * Does nothing if no text items have been added.
777 * May skip the move if --copy-only is set.
780 $originalCount = count( $this->texts
);
781 if ( !$originalCount ) {
785 /* Check to see if the target text_ids have been moved already.
787 * We originally read from the replica DB, so this can happen when a single
788 * text_id is shared between multiple pages. It's rare, but possible
789 * if a delete/move/undelete cycle splits up a null edit.
791 * We do a locking read to prevent closer-run race conditions.
793 $dbw = wfGetDB( DB_MASTER
);
794 $dbw->begin( __METHOD__
);
795 $res = $dbw->select( 'blob_tracking',
796 [ 'bt_text_id', 'bt_moved' ],
797 [ 'bt_text_id' => array_keys( $this->referrers
) ],
798 __METHOD__
, [ 'FOR UPDATE' ] );
800 foreach ( $res as $row ) {
801 if ( $row->bt_moved
) {
802 # This row has already been moved, remove it
803 $this->parent
->debug( "TRX: conflict detected in old_id={$row->bt_text_id}" );
804 unset( $this->texts
[$row->bt_text_id
] );
809 // Recompress the blob if necessary
811 if ( !count( $this->texts
) ) {
812 // All have been moved already
813 if ( $originalCount > 1 ) {
814 // This is suspcious, make noise
815 $this->parent
->critical(
816 "Warning: concurrent operation detected, are there two conflicting " .
817 "processes running, doing the same job?" );
825 // Insert the data into the destination cluster
826 $targetCluster = $this->parent
->getTargetCluster();
827 $store = $this->parent
->store
;
828 $targetDB = $store->getMaster( $targetCluster );
829 $targetDB->clearFlag( DBO_TRX
); // we manage the transactions
830 $targetDB->begin( __METHOD__
);
831 $baseUrl = $this->parent
->store
->store( $targetCluster, serialize( $this->cgz
) );
833 // Write the new URLs to the blob_tracking table
834 foreach ( $this->referrers
as $textId => $hash ) {
835 $url = $baseUrl . '/' . $hash;
836 $dbw->update( 'blob_tracking',
837 [ 'bt_new_url' => $url ],
839 'bt_text_id' => $textId,
840 'bt_moved' => 0, # Check for concurrent conflicting update
846 $targetDB->commit( __METHOD__
);
847 // Critical section here: interruption at this point causes blob duplication
848 // Reversing the order of the commits would cause data loss instead
849 $dbw->commit( __METHOD__
);
851 // Write the new URLs to the text table and set the moved flag
852 if ( !$this->parent
->copyOnly
) {
853 foreach ( $this->referrers
as $textId => $hash ) {
854 $url = $baseUrl . '/' . $hash;
855 $this->parent
->moveTextRow( $textId, $url );