From: Aaron Schulz <aschulz@wikimedia.org>
Date: Thu, 8 Aug 2019 22:53:08 +0000 (-0700)
Subject: rdbms: simplify LoadBalancer::getLaggedReplicaMode()
X-Git-Tag: 1.34.0-rc.0~660^2
X-Git-Url: http://git.cyclocoop.org/%7B%24admin_url%7Dmembres/cotisations/gestion/Special:FilePath/Image2.gif?a=commitdiff_plain;h=21fa1cf121f4350870eb305c0545d458474affab;p=lhc%2Fweb%2Fwiklou.git

rdbms: simplify LoadBalancer::getLaggedReplicaMode()

Remove try/catch since getReaderIndex() is not supposed to throw connection
errors anyway. This makes it easier to tell when "lagged replica" mode is
actually set.

Bug: T216496
Change-Id: Ife974b8da19d3798b2d37424b40c6cadd880e157
---

diff --git a/includes/libs/rdbms/loadbalancer/ILoadBalancer.php b/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
index 990705c45f..112557257f 100644
--- a/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
@@ -167,8 +167,7 @@ interface ILoadBalancer {
 	 *
 	 * @param string|bool $group Query group or false for the generic group
 	 * @param string|bool $domain DB domain ID or false for the local domain
-	 * @throws DBError If no live handle can be obtained
-	 * @return bool|int|string
+	 * @return int|bool Returns false if no live handle can be obtained
 	 */
 	public function getReaderIndex( $group = false, $domain = false );
 
diff --git a/includes/libs/rdbms/loadbalancer/LoadBalancer.php b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
index 98607ce807..d088aa9e54 100644
--- a/includes/libs/rdbms/loadbalancer/LoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
@@ -592,8 +592,7 @@ class LoadBalancer implements ILoadBalancer {
 			$this->connLogger->debug( __METHOD__ . ": Using reader #$i: $serverName..." );
 
 			// Get a connection to this server without triggering other server connections
-			$flags = self::CONN_SILENCE_ERRORS;
-			$conn = $this->getServerConnection( $i, $domain, $flags );
+			$conn = $this->getServerConnection( $i, $domain, self::CONN_SILENCE_ERRORS );
 			if ( !$conn ) {
 				$this->connLogger->warning( __METHOD__ . ": Failed connecting to $i/$domain" );
 				unset( $currentLoads[$i] ); // avoid this server next iteration
@@ -1919,13 +1918,8 @@ class LoadBalancer implements ILoadBalancer {
 		}
 
 		if ( $this->hasStreamingReplicaServers() ) {
-			try {
-				// Set "laggedReplicaMode"
-				$this->getReaderIndex( self::GROUP_GENERIC, $domain );
-			} catch ( DBConnectionError $e ) {
-				// Sanity: avoid expensive re-connect attempts and failures
-				$this->laggedReplicaMode = true;
-			}
+			// This will set "laggedReplicaMode" as needed
+			$this->getReaderIndex( self::GROUP_GENERIC, $domain );
 		}
 
 		return $this->laggedReplicaMode;