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-rw-r--r--includes/objectcache/SqlBagOStuff.php432
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diff --git a/includes/objectcache/SqlBagOStuff.php b/includes/objectcache/SqlBagOStuff.php
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+<?php
+
+/**
+ * Class to store objects in the database
+ *
+ * @ingroup Cache
+ */
+class SqlBagOStuff extends BagOStuff {
+
+ /**
+ * @var LoadBalancer
+ */
+ var $lb;
+
+ /**
+ * @var DatabaseBase
+ */
+ var $db;
+ var $serverInfo;
+ var $lastExpireAll = 0;
+ var $purgePeriod = 100;
+ var $shards = 1;
+ var $tableName = 'objectcache';
+
+ /**
+ * Constructor. Parameters are:
+ * - server: A server info structure in the format required by each
+ * element in $wgDBServers.
+ *
+ * - purgePeriod: The average number of object cache requests in between
+ * garbage collection operations, where expired entries
+ * are removed from the database. Or in other words, the
+ * reciprocal of the probability of purging on any given
+ * request. If this is set to zero, purging will never be
+ * done.
+ *
+ * - tableName: The table name to use, default is "objectcache".
+ *
+ * - shards: The number of tables to use for data storage. If this is
+ * more than 1, table names will be formed in the style
+ * objectcacheNNN where NNN is the shard index, between 0 and
+ * shards-1. The number of digits will be the minimum number
+ * required to hold the largest shard index. Data will be
+ * distributed across all tables by key hash. This is for
+ * MySQL bugs 61735 and 61736.
+ *
+ * @param $params array
+ */
+ public function __construct( $params ) {
+ if ( isset( $params['server'] ) ) {
+ $this->serverInfo = $params['server'];
+ $this->serverInfo['load'] = 1;
+ }
+ if ( isset( $params['purgePeriod'] ) ) {
+ $this->purgePeriod = intval( $params['purgePeriod'] );
+ }
+ if ( isset( $params['tableName'] ) ) {
+ $this->tableName = $params['tableName'];
+ }
+ if ( isset( $params['shards'] ) ) {
+ $this->shards = intval( $params['shards'] );
+ }
+ }
+
+ /**
+ * @return DatabaseBase
+ */
+ protected function getDB() {
+ if ( !isset( $this->db ) ) {
+ # If server connection info was given, use that
+ if ( $this->serverInfo ) {
+ $this->lb = new LoadBalancer( array(
+ 'servers' => array( $this->serverInfo ) ) );
+ $this->db = $this->lb->getConnection( DB_MASTER );
+ $this->db->clearFlag( DBO_TRX );
+ } else {
+ # We must keep a separate connection to MySQL in order to avoid deadlocks
+ # However, SQLite has an opposite behaviour.
+ # @todo Investigate behaviour for other databases
+ if ( wfGetDB( DB_MASTER )->getType() == 'sqlite' ) {
+ $this->db = wfGetDB( DB_MASTER );
+ } else {
+ $this->lb = wfGetLBFactory()->newMainLB();
+ $this->db = $this->lb->getConnection( DB_MASTER );
+ $this->db->clearFlag( DBO_TRX );
+ }
+ }
+ }
+
+ return $this->db;
+ }
+
+ /**
+ * Get the table name for a given key
+ */
+ protected function getTableByKey( $key ) {
+ if ( $this->shards > 1 ) {
+ $hash = hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
+ return $this->getTableByShard( $hash % $this->shards );
+ } else {
+ return $this->tableName;
+ }
+ }
+
+ /**
+ * Get the table name for a given shard index
+ */
+ protected function getTableByShard( $index ) {
+ if ( $this->shards > 1 ) {
+ $decimals = strlen( $this->shards - 1 );
+ return $this->tableName .
+ sprintf( "%0{$decimals}d", $index );
+ } else {
+ return $this->tableName;
+ }
+ }
+
+ public function get( $key ) {
+ # expire old entries if any
+ $this->garbageCollect();
+ $db = $this->getDB();
+ $tableName = $this->getTableByKey( $key );
+ $row = $db->selectRow( $tableName, array( 'value', 'exptime' ),
+ array( 'keyname' => $key ), __METHOD__ );
+
+ if ( !$row ) {
+ $this->debug( 'get: no matching rows' );
+ return false;
+ }
+
+ $this->debug( "get: retrieved data; expiry time is " . $row->exptime );
+
+ if ( $this->isExpired( $row->exptime ) ) {
+ $this->debug( "get: key has expired, deleting" );
+ try {
+ $db->begin();
+ # Put the expiry time in the WHERE condition to avoid deleting a
+ # newly-inserted value
+ $db->delete( $tableName,
+ array(
+ 'keyname' => $key,
+ 'exptime' => $row->exptime
+ ), __METHOD__ );
+ $db->commit();
+ } catch ( DBQueryError $e ) {
+ $this->handleWriteError( $e );
+ }
+
+ return false;
+ }
+
+ return $this->unserialize( $db->decodeBlob( $row->value ) );
+ }
+
+ public function set( $key, $value, $exptime = 0 ) {
+ $db = $this->getDB();
+ $exptime = intval( $exptime );
+
+ if ( $exptime < 0 ) {
+ $exptime = 0;
+ }
+
+ if ( $exptime == 0 ) {
+ $encExpiry = $this->getMaxDateTime();
+ } else {
+ if ( $exptime < 3.16e8 ) { # ~10 years
+ $exptime += time();
+ }
+
+ $encExpiry = $db->timestamp( $exptime );
+ }
+ try {
+ $db->begin();
+ // (bug 24425) use a replace if the db supports it instead of
+ // delete/insert to avoid clashes with conflicting keynames
+ $db->replace(
+ $this->getTableByKey( $key ),
+ array( 'keyname' ),
+ array(
+ 'keyname' => $key,
+ 'value' => $db->encodeBlob( $this->serialize( $value ) ),
+ 'exptime' => $encExpiry
+ ), __METHOD__ );
+ $db->commit();
+ } catch ( DBQueryError $e ) {
+ $this->handleWriteError( $e );
+
+ return false;
+ }
+
+ return true;
+ }
+
+ public function delete( $key, $time = 0 ) {
+ $db = $this->getDB();
+
+ try {
+ $db->begin();
+ $db->delete(
+ $this->getTableByKey( $key ),
+ array( 'keyname' => $key ),
+ __METHOD__ );
+ $db->commit();
+ } catch ( DBQueryError $e ) {
+ $this->handleWriteError( $e );
+
+ return false;
+ }
+
+ return true;
+ }
+
+ public function incr( $key, $step = 1 ) {
+ $db = $this->getDB();
+ $tableName = $this->getTableByKey( $key );
+ $step = intval( $step );
+
+ try {
+ $db->begin();
+ $row = $db->selectRow(
+ $tableName,
+ array( 'value', 'exptime' ),
+ array( 'keyname' => $key ),
+ __METHOD__,
+ array( 'FOR UPDATE' ) );
+ if ( $row === false ) {
+ // Missing
+ $db->commit();
+
+ return null;
+ }
+ $db->delete( $tableName, array( 'keyname' => $key ), __METHOD__ );
+ if ( $this->isExpired( $row->exptime ) ) {
+ // Expired, do not reinsert
+ $db->commit();
+
+ return null;
+ }
+
+ $oldValue = intval( $this->unserialize( $db->decodeBlob( $row->value ) ) );
+ $newValue = $oldValue + $step;
+ $db->insert( $tableName,
+ array(
+ 'keyname' => $key,
+ 'value' => $db->encodeBlob( $this->serialize( $newValue ) ),
+ 'exptime' => $row->exptime
+ ), __METHOD__, 'IGNORE' );
+
+ if ( $db->affectedRows() == 0 ) {
+ // Race condition. See bug 28611
+ $newValue = null;
+ }
+ $db->commit();
+ } catch ( DBQueryError $e ) {
+ $this->handleWriteError( $e );
+
+ return null;
+ }
+
+ return $newValue;
+ }
+
+ public function keys() {
+ $db = $this->getDB();
+ $result = array();
+
+ for ( $i = 0; $i < $this->shards; $i++ ) {
+ $res = $db->select( $this->getTableByShard( $i ),
+ array( 'keyname' ), false, __METHOD__ );
+ foreach ( $res as $row ) {
+ $result[] = $row->keyname;
+ }
+ }
+
+ return $result;
+ }
+
+ protected function isExpired( $exptime ) {
+ return $exptime != $this->getMaxDateTime() && wfTimestamp( TS_UNIX, $exptime ) < time();
+ }
+
+ protected function getMaxDateTime() {
+ if ( time() > 0x7fffffff ) {
+ return $this->getDB()->timestamp( 1 << 62 );
+ } else {
+ return $this->getDB()->timestamp( 0x7fffffff );
+ }
+ }
+
+ protected function garbageCollect() {
+ if ( !$this->purgePeriod ) {
+ // Disabled
+ return;
+ }
+ // Only purge on one in every $this->purgePeriod requests.
+ if ( $this->purgePeriod !== 1 && mt_rand( 0, $this->purgePeriod - 1 ) ) {
+ return;
+ }
+ $now = time();
+ // Avoid repeating the delete within a few seconds
+ if ( $now > ( $this->lastExpireAll + 1 ) ) {
+ $this->lastExpireAll = $now;
+ $this->expireAll();
+ }
+ }
+
+ public function expireAll() {
+ $this->deleteObjectsExpiringBefore( wfTimestampNow() );
+ }
+
+ /**
+ * Delete objects from the database which expire before a certain date.
+ */
+ public function deleteObjectsExpiringBefore( $timestamp ) {
+ $db = $this->getDB();
+ $dbTimestamp = $db->timestamp( $timestamp );
+
+ try {
+ for ( $i = 0; $i < $this->shards; $i++ ) {
+ $db->begin();
+ $db->delete(
+ $this->getTableByShard( $i ),
+ array( 'exptime < ' . $db->addQuotes( $dbTimestamp ) ),
+ __METHOD__ );
+ $db->commit();
+ }
+ } catch ( DBQueryError $e ) {
+ $this->handleWriteError( $e );
+ }
+ return true;
+ }
+
+ public function deleteAll() {
+ $db = $this->getDB();
+
+ try {
+ for ( $i = 0; $i < $this->shards; $i++ ) {
+ $db->begin();
+ $db->delete( $this->getTableByShard( $i ), '*', __METHOD__ );
+ $db->commit();
+ }
+ } catch ( DBQueryError $e ) {
+ $this->handleWriteError( $e );
+ }
+ }
+
+ /**
+ * Serialize an object and, if possible, compress the representation.
+ * On typical message and page data, this can provide a 3X decrease
+ * in storage requirements.
+ *
+ * @param $data mixed
+ * @return string
+ */
+ protected function serialize( &$data ) {
+ $serial = serialize( $data );
+
+ if ( function_exists( 'gzdeflate' ) ) {
+ return gzdeflate( $serial );
+ } else {
+ return $serial;
+ }
+ }
+
+ /**
+ * Unserialize and, if necessary, decompress an object.
+ * @param $serial string
+ * @return mixed
+ */
+ protected function unserialize( $serial ) {
+ if ( function_exists( 'gzinflate' ) ) {
+ wfSuppressWarnings();
+ $decomp = gzinflate( $serial );
+ wfRestoreWarnings();
+
+ if ( false !== $decomp ) {
+ $serial = $decomp;
+ }
+ }
+
+ $ret = unserialize( $serial );
+
+ return $ret;
+ }
+
+ /**
+ * Handle a DBQueryError which occurred during a write operation.
+ * Ignore errors which are due to a read-only database, rethrow others.
+ */
+ protected function handleWriteError( $exception ) {
+ $db = $this->getDB();
+
+ if ( !$db->wasReadOnlyError() ) {
+ throw $exception;
+ }
+
+ try {
+ $db->rollback();
+ } catch ( DBQueryError $e ) {
+ }
+
+ wfDebug( __METHOD__ . ": ignoring query error\n" );
+ $db->ignoreErrors( false );
+ }
+
+ /**
+ * Create shard tables. For use from eval.php.
+ */
+ public function createTables() {
+ $db = $this->getDB();
+ if ( $db->getType() !== 'mysql'
+ || version_compare( $db->getServerVersion(), '4.1.0', '<' ) )
+ {
+ throw new MWException( __METHOD__ . ' is not supported on this DB server' );
+ }
+
+ for ( $i = 0; $i < $this->shards; $i++ ) {
+ $db->begin();
+ $db->query(
+ 'CREATE TABLE ' . $db->tableName( $this->getTableByShard( $i ) ) .
+ ' LIKE ' . $db->tableName( 'objectcache' ),
+ __METHOD__ );
+ $db->commit();
+ }
+ }
+}
+
+/**
+ * Backwards compatibility alias
+ */
+class MediaWikiBagOStuff extends SqlBagOStuff { }
+
generated by cgit v1.2.2 (git 2.25.0) at 2024-04-18 22:38:37 +0000