Merge "Improve lag/flag behavior and docs in LoadBalancer"

[lhc/web/wiklou.git] / includes / libs / rdbms / loadbalancer / LoadBalancer.php

diff --git a/includes/libs/rdbms/loadbalancer/LoadBalancer.php b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
index c78f0ae..7ba21ac 100644 (file)
--- a/includes/libs/rdbms/loadbalancer/LoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
@@ -23,7 +23,7 @@
 use Psr\Log\LoggerInterface;
 
 /**
- * Database load balancing, tracking, and transaction management object
+ * Database connection, tracking, load balancing, and transaction manager for a cluster
  *
  * @ingroup Database
  */
@@ -801,14 +801,18 @@ class LoadBalancer implements ILoadBalancer {
                }
 
                $server['srvCache'] = $this->srvCache;
-               // Set loggers
+               // Set loggers and profilers
                $server['connLogger'] = $this->connLogger;
                $server['queryLogger'] = $this->queryLogger;
+               $server['errorLogger'] = $this->errorLogger;
                $server['profiler'] = $this->profiler;
                $server['trxProfiler'] = $this->trxProfiler;
+               // Use the same agent and PHP mode for all DB handles
                $server['cliMode'] = $this->cliMode;
-               $server['errorLogger'] = $this->errorLogger;
                $server['agent'] = $this->agent;
+               // Use DBO_DEFAULT flags by default for LoadBalancer managed databases. Assume that the
+               // application calls LoadBalancer::commitMasterChanges() before the PHP script completes.
+               $server['flags'] = isset( $server['flags'] ) ? $server['flags'] : DBO_DEFAULT;
 
                // Create a live connection object
                try {
@@ -821,7 +825,7 @@ class LoadBalancer implements ILoadBalancer {
 
                $db->setLBInfo( $server );
                $db->setLazyMasterHandle(
-                       $this->getLazyConnectionRef( DB_MASTER, [], $db->getWikiID() )
+                       $this->getLazyConnectionRef( DB_MASTER, [], $db->getDomainID() )
                );
                $db->setTableAliases( $this->tableAliases );
 
@@ -1390,11 +1394,20 @@ class LoadBalancer implements ILoadBalancer {
 
        public function getLagTimes( $domain = false ) {
                if ( $this->getServerCount() <= 1 ) {
-                       return [ 0 => 0 ]; // no replication = no lag
+                       return [ $this->getWriterIndex() => 0 ]; // no replication = no lag
+               }
+
+               $knownLagTimes = []; // map of (server index => 0 seconds)
+               $indexesWithLag = [];
+               foreach ( $this->mServers as $i => $server ) {
+                       if ( empty( $server['is static'] ) ) {
+                               $indexesWithLag[] = $i; // DB server might have replication lag
+                       } else {
+                               $knownLagTimes[$i] = 0; // DB server is a non-replicating and read-only archive
+                       }
                }
 
-               # Send the request to the load monitor
-               return $this->getLoadMonitor()->getLagTimes( array_keys( $this->mServers ), $domain );
+               return $this->getLoadMonitor()->getLagTimes( $indexesWithLag, $domain ) + $knownLagTimes;
        }
 
        public function safeGetLag( IDatabase $conn ) {