From 36dfd18409e414f4df2aef016753a8cb637b6bac Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Fri, 9 Feb 2018 11:28:59 -0800
Subject: [PATCH] Avoid pointless DB_MASTER connections in
 User::clearSharedCache()

Change-Id: Ifc4f489cea4460185cb2d8317f174cabd67f5862
---
 includes/user/User.php | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/includes/user/User.php b/includes/user/User.php
index 97035c2dab..eeade49db6 100644
--- a/includes/user/User.php
+++ b/includes/user/User.php
@@ -2509,12 +2509,17 @@ class User implements IDBAccessObject, UserIdentity {
 		if ( $mode === 'refresh' ) {
 			$cache->delete( $key, 1 );
 		} else {
-			wfGetDB( DB_MASTER )->onTransactionPreCommitOrIdle(
-				function () use ( $cache, $key ) {
-					$cache->delete( $key );
-				},
-				__METHOD__
-			);
+			$lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
+			if ( $lb->hasOrMadeRecentMasterChanges() ) {
+				$lb->getConnection( DB_MASTER )->onTransactionPreCommitOrIdle(
+					function () use ( $cache, $key ) {
+						$cache->delete( $key );
+					},
+					__METHOD__
+				);
+			} else {
+				$cache->delete( $key );
+			}
 		}
 	}
 
-- 
2.20.1