From: Aaron Schulz <aschulz@wikimedia.org>
Date: Tue, 21 Nov 2017 02:09:52 +0000 (-0800)
Subject: Reduce lag waiting time in CategoryMembershipUpdateJob critical section
X-Git-Tag: 1.31.0-rc.0~1442^2
X-Git-Url: http://git.cyclocoop.org/%24action?a=commitdiff_plain;h=b212286144a2454b0a9c68f874d646bbf271ab8b;p=lhc%2Fweb%2Fwiklou.git

Reduce lag waiting time in CategoryMembershipUpdateJob critical section

Bug: T180793
Change-Id: Icfe8dd16f4194c5d4f88d7547f732acae8b1cfe2
---

diff --git a/includes/jobqueue/jobs/CategoryMembershipChangeJob.php b/includes/jobqueue/jobs/CategoryMembershipChangeJob.php
index 55c1367c23..cc81a96422 100644
--- a/includes/jobqueue/jobs/CategoryMembershipChangeJob.php
+++ b/includes/jobqueue/jobs/CategoryMembershipChangeJob.php
@@ -59,6 +59,13 @@ class CategoryMembershipChangeJob extends Job {
 			return false; // deleted?
 		}
 
+		// Cut down on the time spent in safeWaitForMasterPos() in the critical section
+		$dbr = $lb->getConnection( DB_REPLICA, [ 'recentchanges' ] );
+		if ( !$lb->safeWaitForMasterPos( $dbr ) ) {
+			$this->setLastError( "Timed out while pre-waiting for replica DB to catch up" );
+			return false;
+		}
+
 		// Use a named lock so that jobs for this page see each others' changes
 		$lockKey = "CategoryMembershipUpdates:{$page->getId()}";
 		$scopedLock = $dbw->getScopedLockAndFlush( $lockKey, __METHOD__, 3 );
@@ -67,8 +74,7 @@ class CategoryMembershipChangeJob extends Job {
 			return false;
 		}
 
-		$dbr = $lb->getConnection( DB_REPLICA, [ 'recentchanges' ] );
-		// Wait till the replica DB is caught up so that jobs for this page see each others' changes
+		// Wait till replica DB is caught up so that jobs for this page see each others' changes
 		if ( !$lb->safeWaitForMasterPos( $dbr ) ) {
 			$this->setLastError( "Timed out while waiting for replica DB to catch up" );
 			return false;