rdbms: make getMasterPos() ignore GTIDs outside of gtid_domain_id
[lhc/web/wiklou.git] / includes / libs / rdbms / database / DatabaseMysqlBase.php
index c7147e4..286d658 100644 (file)
@@ -70,6 +70,9 @@ abstract class DatabaseMysqlBase extends Database {
        /** @var stdClass|null */
        private $replicationInfoRow = null;
 
+       // Cache getServerId() for 24 hours
+       const SERVER_ID_CACHE_TTL = 86400;
+
        /**
         * Additional $params include:
         *   - lagDetectionMethod : set to one of (Seconds_Behind_Master,pt-heartbeat).
@@ -902,18 +905,23 @@ abstract class DatabaseMysqlBase extends Database {
                        }
                        // Wait on the GTID set (MariaDB only)
                        $gtidArg = $this->addQuotes( implode( ',', $gtidsWait ) );
-                       $res = $this->doQuery( "SELECT MASTER_GTID_WAIT($gtidArg, $timeout)" );
+                       if ( strpos( $gtidArg, ':' ) !== false ) {
+                               // MySQL GTIDs, e.g "source_id:transaction_id"
+                               $res = $this->doQuery( "SELECT WAIT_FOR_EXECUTED_GTID_SET($gtidArg, $timeout)" );
+                       } else {
+                               // MariaDB GTIDs, e.g."domain:server:sequence"
+                               $res = $this->doQuery( "SELECT MASTER_GTID_WAIT($gtidArg, $timeout)" );
+                       }
                } else {
                        // Wait on the binlog coordinates
                        $encFile = $this->addQuotes( $pos->getLogFile() );
-                       $encPos = intval( $pos->pos[1] );
+                       $encPos = intval( $pos->getLogPosition()[$pos::CORD_EVENT] );
                        $res = $this->doQuery( "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)" );
                }
 
                $row = $res ? $this->fetchRow( $res ) : false;
                if ( !$row ) {
-                       throw new DBExpectedError( $this,
-                               "MASTER_POS_WAIT() or MASTER_GTID_WAIT() failed: {$this->lastError()}" );
+                       throw new DBExpectedError( $this, "Replication wait failed: {$this->lastError()}" );
                }
 
                // Result can be NULL (error), -1 (timeout), or 0+ per the MySQL manual
@@ -945,21 +953,23 @@ abstract class DatabaseMysqlBase extends Database {
         * @return MySQLMasterPos|bool
         */
        public function getReplicaPos() {
-               $now = microtime( true );
-
-               if ( $this->useGTIDs ) {
-                       $res = $this->query( "SELECT @@global.gtid_slave_pos AS Value", __METHOD__ );
-                       $gtidRow = $this->fetchObject( $res );
-                       if ( $gtidRow && strlen( $gtidRow->Value ) ) {
-                               return new MySQLMasterPos( $gtidRow->Value, $now );
+               $now = microtime( true ); // as-of-time *before* fetching GTID variables
+
+               if ( $this->useGTIDs() ) {
+                       // Try to use GTIDs, fallbacking to binlog positions if not possible
+                       $data = $this->getServerGTIDs( __METHOD__ );
+                       // Use gtid_current_pos for MariaDB and gtid_executed for MySQL
+                       foreach ( [ 'gtid_current_pos', 'gtid_executed' ] as $name ) {
+                               if ( isset( $data[$name] ) && strlen( $data[$name] ) ) {
+                                       return new MySQLMasterPos( $data[$name], $now );
+                               }
                        }
                }
 
-               $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
-               $row = $this->fetchObject( $res );
-               if ( $row && strlen( $row->Relay_Master_Log_File ) ) {
+               $data = $this->getServerRoleStatus( 'SLAVE', __METHOD__ );
+               if ( $data && strlen( $data['Relay_Master_Log_File'] ) ) {
                        return new MySQLMasterPos(
-                               "{$row->Relay_Master_Log_File}/{$row->Exec_Master_Log_Pos}",
+                               "{$data['Relay_Master_Log_File']}/{$data['Exec_Master_Log_Pos']}",
                                $now
                        );
                }
@@ -973,23 +983,97 @@ abstract class DatabaseMysqlBase extends Database {
         * @return MySQLMasterPos|bool
         */
        public function getMasterPos() {
-               $now = microtime( true );
+               $now = microtime( true ); // as-of-time *before* fetching GTID variables
+
+               $pos = false;
+               if ( $this->useGTIDs() ) {
+                       // Try to use GTIDs, fallbacking to binlog positions if not possible
+                       $data = $this->getServerGTIDs( __METHOD__ );
+                       // Use gtid_current_pos for MariaDB and gtid_executed for MySQL
+                       foreach ( [ 'gtid_current_pos', 'gtid_executed' ] as $name ) {
+                               if ( isset( $data[$name] ) && strlen( $data[$name] ) ) {
+                                       $pos = new MySQLMasterPos( $data[$name], $now );
+                                       break;
+                               }
+                       }
+                       // Filter domains that are inactive or not relevant to the session
+                       if ( $pos ) {
+                               $pos->setActiveOriginServerId( $this->getServerId() );
+                               $pos->setActiveOriginServerUUID( $this->getServerUUID() );
+                               if ( isset( $data['gtid_domain_id'] ) ) {
+                                       $pos->setActiveDomain( $data['gtid_domain_id'] );
+                               }
+                       }
+               }
 
-               if ( $this->useGTIDs ) {
-                       $res = $this->query( "SELECT @@global.gtid_binlog_pos AS Value", __METHOD__ );
-                       $gtidRow = $this->fetchObject( $res );
-                       if ( $gtidRow && strlen( $gtidRow->Value ) ) {
-                               return new MySQLMasterPos( $gtidRow->Value, $now );
+               if ( !$pos ) {
+                       $data = $this->getServerRoleStatus( 'MASTER', __METHOD__ );
+                       if ( $data && strlen( $data['File'] ) ) {
+                               $pos = new MySQLMasterPos( "{$data['File']}/{$data['Position']}", $now );
                        }
                }
 
-               $res = $this->query( 'SHOW MASTER STATUS', __METHOD__ );
-               $row = $this->fetchObject( $res );
-               if ( $row && strlen( $row->File ) ) {
-                       return new MySQLMasterPos( "{$row->File}/{$row->Position}", $now );
+               return $pos;
+       }
+
+       /**
+        * @return int
+        * @throws DBQueryError If the variable doesn't exist for some reason
+        */
+       protected function getServerId() {
+               return $this->srvCache->getWithSetCallback(
+                       $this->srvCache->makeGlobalKey( 'mysql-server-id', $this->getServer() ),
+                       self::SERVER_ID_CACHE_TTL,
+                       function () {
+                               $res = $this->query( "SELECT @@server_id AS id", __METHOD__ );
+                               return intval( $this->fetchObject( $res )->id );
+                       }
+               );
+       }
+
+       /**
+        * @return string|null
+        */
+       protected function getServerUUID() {
+               return $this->srvCache->getWithSetCallback(
+                       $this->srvCache->makeGlobalKey( 'mysql-server-uuid', $this->getServer() ),
+                       self::SERVER_ID_CACHE_TTL,
+                       function () {
+                               $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'server_uuid'" );
+                               $row = $this->fetchObject( $res );
+
+                               return $row ? $row->Value : null;
+                       }
+               );
+       }
+
+       /**
+        * @param string $fname
+        * @return string[]
+        */
+       protected function getServerGTIDs( $fname = __METHOD__ ) {
+               $map = [];
+               // Get global-only variables like gtid_executed
+               $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'gtid_%'", $fname );
+               foreach ( $res as $row ) {
+                       $map[$row->Variable_name] = $row->Value;
+               }
+               // Get session-specific (e.g. gtid_domain_id since that is were writes will log)
+               $res = $this->query( "SHOW SESSION VARIABLES LIKE 'gtid_%'", $fname );
+               foreach ( $res as $row ) {
+                       $map[$row->Variable_name] = $row->Value;
                }
 
-               return false;
+               return $map;
+       }
+
+       /**
+        * @param string $role One of "MASTER"/"SLAVE"
+        * @param string $fname
+        * @return string[] Latest available server status row
+        */
+       protected function getServerRoleStatus( $role, $fname = __METHOD__ ) {
+               return $this->query( "SHOW $role STATUS", $fname )->fetchRow() ?: [];
        }
 
        public function serverIsReadOnly() {
@@ -1434,6 +1518,12 @@ abstract class DatabaseMysqlBase extends Database {
                return 'CAST( ' . $field . ' AS SIGNED )';
        }
 
+       /*
+        * @return bool Whether GTID support is used (mockable for testing)
+        */
+       protected function useGTIDs() {
+               return $this->useGTIDs;
+       }
 }
 
 class_alias( DatabaseMysqlBase::class, 'DatabaseMysqlBase' );