MediaWiki 1.30.2-scripts

[autoinstalls/mediawiki.git] / includes / libs / lockmanager / PostgreSqlLockManager.php

diff --git a/includes/libs/lockmanager/PostgreSqlLockManager.php b/includes/libs/lockmanager/PostgreSqlLockManager.php
new file mode 100644 (file)
index 0000000..65c6993
--- /dev/null
+++ b/includes/libs/lockmanager/PostgreSqlLockManager.php
@@ -0,0 +1,82 @@
+<?php
+
+use Wikimedia\Rdbms\DBError;
+
+/**
+ * PostgreSQL version of DBLockManager that supports shared locks.
+ * All locks are non-blocking, which avoids deadlocks.
+ *
+ * @ingroup LockManager
+ */
+class PostgreSqlLockManager extends DBLockManager {
+       /** @var array Mapping of lock types to the type actually used */
+       protected $lockTypeMap = [
+               self::LOCK_SH => self::LOCK_SH,
+               self::LOCK_UW => self::LOCK_SH,
+               self::LOCK_EX => self::LOCK_EX
+       ];
+
+       protected function doGetLocksOnServer( $lockSrv, array $paths, $type ) {
+               $status = StatusValue::newGood();
+               if ( !count( $paths ) ) {
+                       return $status; // nothing to lock
+               }
+
+               $db = $this->getConnection( $lockSrv ); // checked in isServerUp()
+               $bigints = array_unique( array_map(
+                       function ( $key ) {
+                               return Wikimedia\base_convert( substr( $key, 0, 15 ), 16, 10 );
+                       },
+                       array_map( [ $this, 'sha1Base16Absolute' ], $paths )
+               ) );
+
+               // Try to acquire all the locks...
+               $fields = [];
+               foreach ( $bigints as $bigint ) {
+                       $fields[] = ( $type == self::LOCK_SH )
+                               ? "pg_try_advisory_lock_shared({$db->addQuotes( $bigint )}) AS K$bigint"
+                               : "pg_try_advisory_lock({$db->addQuotes( $bigint )}) AS K$bigint";
+               }
+               $res = $db->query( 'SELECT ' . implode( ', ', $fields ), __METHOD__ );
+               $row = $res->fetchRow();
+
+               if ( in_array( 'f', $row ) ) {
+                       // Release any acquired locks if some could not be acquired...
+                       $fields = [];
+                       foreach ( $row as $kbigint => $ok ) {
+                               if ( $ok === 't' ) { // locked
+                                       $bigint = substr( $kbigint, 1 ); // strip off the "K"
+                                       $fields[] = ( $type == self::LOCK_SH )
+                                               ? "pg_advisory_unlock_shared({$db->addQuotes( $bigint )})"
+                                               : "pg_advisory_unlock({$db->addQuotes( $bigint )})";
+                               }
+                       }
+                       if ( count( $fields ) ) {
+                               $db->query( 'SELECT ' . implode( ', ', $fields ), __METHOD__ );
+                       }
+                       foreach ( $paths as $path ) {
+                               $status->fatal( 'lockmanager-fail-acquirelock', $path );
+                       }
+               }
+
+               return $status;
+       }
+
+       /**
+        * @see QuorumLockManager::releaseAllLocks()
+        * @return StatusValue
+        */
+       protected function releaseAllLocks() {
+               $status = StatusValue::newGood();
+
+               foreach ( $this->conns as $lockDb => $db ) {
+                       try {
+                               $db->query( "SELECT pg_advisory_unlock_all()", __METHOD__ );
+                       } catch ( DBError $e ) {
+                               $status->fatal( 'lockmanager-fail-db-release', $lockDb );
+                       }
+               }
+
+               return $status;
+       }
+}