Make wikidiff3 the only diff engine

[lhc/web/wiklou.git] / includes / db / DatabaseMysqlBase.php

diff --git a/includes/db/DatabaseMysqlBase.php b/includes/db/DatabaseMysqlBase.php
index 1e27205..13be911 100644 (file)
--- a/includes/db/DatabaseMysqlBase.php
+++ b/includes/db/DatabaseMysqlBase.php
@@ -34,6 +34,8 @@ abstract class DatabaseMysqlBase extends Database {
        protected $lastKnownSlavePos;
        /** @var string Method to detect slave lag */
        protected $lagDetectionMethod;
+       /** @var array Method to detect slave lag */
+       protected $lagDetectionOptions = [];
 
        /** @var string|null */
        private $serverVersion = null;
@@ -44,6 +46,10 @@ abstract class DatabaseMysqlBase extends Database {
         *                          pt-heartbeat assumes the table is at heartbeat.heartbeat
         *                          and uses UTC timestamps in the heartbeat.ts column.
         *                          (https://www.percona.com/doc/percona-toolkit/2.2/pt-heartbeat.html)
+        *   - lagDetectionOptions : if using pt-heartbeat, this can be set to an array map to change
+        *                           the default behavior. Normally, the heartbeat row with the server
+        *                           ID of this server's master will be used. Set the "conds" field to
+        *                           override the query conditions, e.g. ['shard' => 's1'].
         * @param array $params
         */
        function __construct( array $params ) {
@@ -52,6 +58,9 @@ abstract class DatabaseMysqlBase extends Database {
                $this->lagDetectionMethod = isset( $params['lagDetectionMethod'] )
                        ? $params['lagDetectionMethod']
                        : 'Seconds_Behind_Master';
+               $this->lagDetectionOptions = isset( $params['lagDetectionOptions'] )
+                       ? $params['lagDetectionOptions']
+                       : [];
        }
 
        /**
@@ -652,19 +661,30 @@ abstract class DatabaseMysqlBase extends Database {
         * @return bool|float
         */
        protected function getLagFromPtHeartbeat() {
-               $masterInfo = $this->getMasterServerInfo();
-               if ( !$masterInfo ) {
-                       wfLogDBError(
-                               "Unable to query master of {db_server} for server ID",
-                               $this->getLogContext( [
-                                       'method' => __METHOD__
-                               ] )
-                       );
+               $options = $this->lagDetectionOptions;
+
+               if ( isset( $options['conds'] ) ) {
+                       // Best method for multi-DC setups: use logical channel names
+                       $data = $this->getHeartbeatData( $options['conds'] );
+               } else {
+                       // Standard method: use master server ID (works with stock pt-heartbeat)
+                       $masterInfo = $this->getMasterServerInfo();
+                       if ( !$masterInfo ) {
+                               wfLogDBError(
+                                       "Unable to query master of {db_server} for server ID",
+                                       $this->getLogContext( [
+                                               'method' => __METHOD__
+                                       ] )
+                               );
+
+                               return false; // could not get master server ID
+                       }
 
-                       return false; // could not get master server ID
+                       $conds = [ 'server_id' => intval( $masterInfo['serverId'] ) ];
+                       $data = $this->getHeartbeatData( $conds );
                }
 
-               list( $time, $nowUnix ) = $this->getHeartbeatData( $masterInfo['serverId'] );
+               list( $time, $nowUnix ) = $data;
                if ( $time !== null ) {
                        // @time is in ISO format like "2015-09-25T16:48:10.000510"
                        $dateTime = new DateTime( $time, new DateTimeZone( 'UTC' ) );
@@ -722,17 +742,17 @@ abstract class DatabaseMysqlBase extends Database {
        }
 
        /**
-        * @param string $masterId Server ID
-        * @return array (heartbeat `ts` column value or null, UNIX timestamp)
+        * @param array $conds WHERE clause conditions to find a row
+        * @return array (heartbeat `ts` column value or null, UNIX timestamp) for the newest beat
         * @see https://www.percona.com/doc/percona-toolkit/2.1/pt-heartbeat.html
         */
-       protected function getHeartbeatData( $masterId ) {
-               // Get the status row for this master; use the oldest for sanity in case the master
-               // has entries listed under different server IDs (which should really not happen).
-               // Note: this would use "MAX(TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6)))" but the
+       protected function getHeartbeatData( array $conds ) {
+               $whereSQL = $this->makeList( $conds, LIST_AND );
+               // Use ORDER BY for channel based queries since that field might not be UNIQUE.
+               // Note: this would use "TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6))" but the
                // percision field is not supported in MySQL <= 5.5.
                $res = $this->query(
-                       "SELECT ts FROM heartbeat.heartbeat WHERE server_id=" . intval( $masterId )
+                       "SELECT ts FROM heartbeat.heartbeat WHERE $whereSQL ORDER BY ts DESC LIMIT 1"
                );
                $row = $res ? $res->fetchObject() : false;