From: Aaron Schulz <aschulz@wikimedia.org>
Date: Wed, 18 May 2016 23:03:27 +0000 (-0700)
Subject: Support non-replicating DB clusters for static datasets
X-Git-Tag: 1.31.0-rc.0~6835^2
X-Git-Url: https://git.cyclocoop.org/%27.WWW_URL.%27admin/?a=commitdiff_plain;h=dad87efa5a431a06a4a379b606346cf93d85ae7d;p=lhc%2Fweb%2Fwiklou.git

Support non-replicating DB clusters for static datasets

* Make the slave wait methods work properly in this case if
  the config flag is set.
* Also fixed a small IDEA error.

Bug: T135690
Change-Id: I9a12f1fc54c0b426f64c19ac2bf720e683fcf2fe
---

diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index d6db388573..a542ed84e9 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -1902,6 +1902,7 @@ $wgSharedSchema = false;
  *                                    if available
  *
  *   - max lag:     (optional) Maximum replication lag before a slave will taken out of rotation
+ *   - is static:   (optional) Set to true if the dataset is static and no replication is used.
  *
  *   These and any other user-defined properties will be assigned to the mLBInfo member
  *   variable of the Database object.
diff --git a/includes/db/DatabaseMysqlBase.php b/includes/db/DatabaseMysqlBase.php
index 13be911686..3ebc3ecce1 100644
--- a/includes/db/DatabaseMysqlBase.php
+++ b/includes/db/DatabaseMysqlBase.php
@@ -782,8 +782,10 @@ abstract class DatabaseMysqlBase extends Database {
 			throw new InvalidArgumentException( "Position not an instance of MySQLMasterPos" );
 		}
 
-		if ( $this->lastKnownSlavePos && $this->lastKnownSlavePos->hasReached( $pos ) ) {
-			return 0;
+		if ( $this->getLBInfo( 'is static' ) === true ) {
+			return 0; // this is a copy of a read-only dataset with no master DB
+		} elseif ( $this->lastKnownSlavePos && $this->lastKnownSlavePos->hasReached( $pos ) ) {
+			return 0; // already reached this point for sure
 		}
 
 		# Commit any open transactions
diff --git a/includes/db/loadbalancer/LoadBalancer.php b/includes/db/loadbalancer/LoadBalancer.php
index 557809905c..43da2180ff 100644
--- a/includes/db/loadbalancer/LoadBalancer.php
+++ b/includes/db/loadbalancer/LoadBalancer.php
@@ -1402,7 +1402,7 @@ class LoadBalancer {
 		}
 
 		$pos = $pos ?: $this->getConnection( DB_MASTER )->getMasterPos();
-		if ( !$pos ) {
+		if ( !( $pos instanceof DBMasterPos ) ) {
 			return false; // something is misconfigured
 		}