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| 1 | <?php |
| 2 | /** |
| 3 | * @license GPL-2.0-or-later |
| 4 | * @file |
| 5 | */ |
| 6 | |
| 7 | // @codeCoverageIgnoreStart |
| 8 | require_once __DIR__ . '/Maintenance.php'; |
| 9 | // @codeCoverageIgnoreEnd |
| 10 | |
| 11 | use MediaWiki\MainConfigNames; |
| 12 | use MediaWiki\Maintenance\Maintenance; |
| 13 | use Wikimedia\Timestamp\ConvertibleTimestamp; |
| 14 | use Wikimedia\Timestamp\TimestampFormat as TS; |
| 15 | |
| 16 | /** |
| 17 | * Remove expired objects from the parser cache database. |
| 18 | * |
| 19 | * By default, this does not need to be run. The default parser cache |
| 20 | * backend is CACHE_DB (SqlBagOStuff), and by default that automatically |
| 21 | * performs incremental purges in the background of write requests. |
| 22 | * Check your wiki's $wgParserCacheType setting to determine if you need to run this script. |
| 23 | * |
| 24 | * @ingroup Maintenance |
| 25 | */ |
| 26 | class PurgeParserCache extends Maintenance { |
| 27 | |
| 28 | /** @var null|string */ |
| 29 | private $lastProgress; |
| 30 | |
| 31 | /** @var null|float */ |
| 32 | private $lastTimestamp; |
| 33 | |
| 34 | /** @var int */ |
| 35 | private $tmpCount = 0; |
| 36 | /** @var float */ |
| 37 | private $usleep = 0; |
| 38 | |
| 39 | public function __construct() { |
| 40 | parent::__construct(); |
| 41 | $this->addDescription( "Remove old objects from the parser cache. " . |
| 42 | "This only works when the parser cache is in an SQL database." ); |
| 43 | $this->addOption( 'expiredate', 'Delete objects expiring before this date.', false, true ); |
| 44 | $this->addOption( |
| 45 | 'age', |
| 46 | 'Delete objects created more than this many seconds ago, assuming ' . |
| 47 | '$wgParserCacheExpireTime has remained consistent.', |
| 48 | false, |
| 49 | true ); |
| 50 | $this->addOption( 'dry-run', 'Perform a dry run, to verify age and date calculation.' ); |
| 51 | $this->addOption( 'msleep', 'Milliseconds to sleep between purge chunks of $wgUpdateRowsPerQuery.', |
| 52 | false, |
| 53 | true ); |
| 54 | $this->addOption( |
| 55 | 'tag', |
| 56 | 'Purge a single server only. This feature is designed for use by large wiki farms where ' . |
| 57 | 'one has to purge multiple servers concurrently in order to keep up with new writes. ' . |
| 58 | 'This requires using the SqlBagOStuff "servers" option in $wgObjectCaches.', |
| 59 | false, |
| 60 | true ); |
| 61 | } |
| 62 | |
| 63 | public function execute() { |
| 64 | $inputDate = $this->getOption( 'expiredate' ); |
| 65 | $inputAge = $this->getOption( 'age' ); |
| 66 | |
| 67 | if ( $inputDate !== null ) { |
| 68 | $timestamp = strtotime( $inputDate ); |
| 69 | } elseif ( $inputAge !== null ) { |
| 70 | $expireTime = (int)$this->getConfig()->get( MainConfigNames::ParserCacheExpireTime ); |
| 71 | $timestamp = time() + $expireTime - intval( $inputAge ); |
| 72 | } else { |
| 73 | $this->fatalError( "Must specify either --expiredate or --age" ); |
| 74 | } |
| 75 | $this->usleep = 1e3 * $this->getOption( 'msleep', 0 ); |
| 76 | $this->lastTimestamp = microtime( true ); |
| 77 | |
| 78 | $humanDate = ConvertibleTimestamp::convert( TS::RFC2822, $timestamp ); |
| 79 | if ( $this->hasOption( 'dry-run' ) ) { |
| 80 | $this->fatalError( "\nDry run mode, would delete objects having an expiry before " . $humanDate . "\n" ); |
| 81 | } |
| 82 | |
| 83 | $this->output( "Deleting objects expiring before " . $humanDate . "\n" ); |
| 84 | |
| 85 | $pc = $this->getServiceContainer()->getParserCache()->getCacheStorage(); |
| 86 | $success = $pc->deleteObjectsExpiringBefore( |
| 87 | $timestamp, |
| 88 | $this->showProgressAndWait( ... ), |
| 89 | INF, |
| 90 | // Note that "0" can be a valid server tag, and must not be discarded or changed to null. |
| 91 | $this->getOption( 'tag', null ) |
| 92 | ); |
| 93 | if ( !$success ) { |
| 94 | $this->fatalError( "\nCannot purge this kind of parser cache." ); |
| 95 | } |
| 96 | $this->showProgressAndWait( 100 ); |
| 97 | $this->output( "\nDone\n" ); |
| 98 | } |
| 99 | |
| 100 | private function showProgressAndWait( int $percent ) { |
| 101 | // Parser caches involve mostly-unthrottled writes of large blobs. This is sometimes prone |
| 102 | // to replication lag. As such, while our purge queries are simple primary key deletes, |
| 103 | // we want to avoid adding significant load to the replication stream, by being |
| 104 | // proactively graceful with these sleeps between each batch. |
| 105 | // The reason we don't explicitly wait for replication is that that would require the script |
| 106 | // to be aware of cross-dc replicas, which we prefer not to, and waiting for replication |
| 107 | // and confirmation latency might actually be *too* graceful and take so long that the |
| 108 | // purge script would not be able to finish within 24 hours for large wiki farms. |
| 109 | // (T150124). |
| 110 | usleep( $this->usleep ); |
| 111 | $this->tmpCount++; |
| 112 | |
| 113 | $percentString = sprintf( "%.1f", $percent ); |
| 114 | if ( $percentString === $this->lastProgress ) { |
| 115 | // Only print a line if we've progressed >= 0.1% since the last printed line. |
| 116 | // This does not mean every 0.1% step is printed since we only run this callback |
| 117 | // once after a deletion batch. How often and how many lines we print depends on the |
| 118 | // batch size (SqlBagOStuff::deleteObjectsExpiringBefore, $wgUpdateRowsPerQuery), |
| 119 | // and on how many table rows there are. |
| 120 | return; |
| 121 | } |
| 122 | $now = microtime( true ); |
| 123 | $sec = sprintf( "%.1f", $now - $this->lastTimestamp ); |
| 124 | |
| 125 | // Give a sense of how much time is spent in the delete operations vs the sleep time, |
| 126 | // by recording the number of iterations we've completed since the last progress update. |
| 127 | $this->output( "... {$percentString}% done (+{$this->tmpCount} iterations in {$sec}s)\n" ); |
| 128 | |
| 129 | $this->lastProgress = $percentString; |
| 130 | $this->tmpCount = 0; |
| 131 | $this->lastTimestamp = $now; |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | // @codeCoverageIgnoreStart |
| 136 | $maintClass = PurgeParserCache::class; |
| 137 | require_once RUN_MAINTENANCE_IF_MAIN; |
| 138 | // @codeCoverageIgnoreEnd |