rdbms: reduce LoadBalancer replication log spam

[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 2a6175f..ca18122 100644 (file)
--- a/includes/libs/rdbms/loadbalancer/LoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
@@ -312,7 +312,7 @@ class LoadBalancer implements ILoadBalancer {
                                                ": server {host} is not replicating?", [ 'host' => $host ] );
                                        unset( $loads[$i] );
                                } elseif ( $lag > $maxServerLag ) {
-                                       $this->replLogger->info(
+                                       $this->replLogger->debug(
                                                __METHOD__ .
                                                ": server {host} has {lag} seconds of lag (>= {maxlag})",
                                                [ 'host' => $host, 'lag' => $lag, 'maxlag' => $maxServerLag ]
@@ -985,6 +985,8 @@ class LoadBalancer implements ILoadBalancer {
                }
 
                /** @var Database $conn */
+               $conn = null;
+
                if ( isset( $this->conns[$connInUseKey][$i][$domain] ) ) {
                        // Reuse an in-use connection for the same domain
                        $conn = $this->conns[$connInUseKey][$i][$domain];
@@ -996,22 +998,36 @@ class LoadBalancer implements ILoadBalancer {
                        $this->conns[$connInUseKey][$i][$domain] = $conn;
                        $this->connLogger->debug( __METHOD__ . ": reusing free connection $i/$domain" );
                } elseif ( !empty( $this->conns[$connFreeKey][$i] ) ) {
-                       // Reuse a free connection from another domain
-                       $conn = reset( $this->conns[$connFreeKey][$i] );
-                       $oldDomain = key( $this->conns[$connFreeKey][$i] );
-                       if ( $domainInstance->getDatabase() !== null ) {
-                               $conn->selectDomain( $domainInstance );
-                       } else {
-                               // Stay on the current database, but update the schema/prefix
-                               $conn->dbSchema( $domainInstance->getSchema() );
-                               $conn->tablePrefix( $domainInstance->getTablePrefix() );
+                       // Reuse a free connection from another domain if possible
+                       foreach ( $this->conns[$connFreeKey][$i] as $oldDomain => $conn ) {
+                               if ( $domainInstance->getDatabase() !== null ) {
+                                       // Check if changing the database will require a new connection.
+                                       // In that case, leave the connection handle alone and keep looking.
+                                       // This prevents connections from being closed mid-transaction and can
+                                       // also avoid overhead if the same database will later be requested.
+                                       if (
+                                               $conn->databasesAreIndependent() &&
+                                               $conn->getDBname() !== $domainInstance->getDatabase()
+                                       ) {
+                                               continue;
+                                       }
+                                       // Select the new database, schema, and prefix
+                                       $conn->selectDomain( $domainInstance );
+                               } else {
+                                       // Stay on the current database, but update the schema/prefix
+                                       $conn->dbSchema( $domainInstance->getSchema() );
+                                       $conn->tablePrefix( $domainInstance->getTablePrefix() );
+                               }
+                               unset( $this->conns[$connFreeKey][$i][$oldDomain] );
+                               // Note that if $domain is an empty string, getDomainID() might not match it
+                               $this->conns[$connInUseKey][$i][$conn->getDomainId()] = $conn;
+                               $this->connLogger->debug( __METHOD__ .
+                                       ": reusing free connection from $oldDomain for $domain" );
+                               break;
                        }
-                       unset( $this->conns[$connFreeKey][$i][$oldDomain] );
-                       // Note that if $domain is an empty string, getDomainID() might not match it
-                       $this->conns[$connInUseKey][$i][$conn->getDomainId()] = $conn;
-                       $this->connLogger->debug( __METHOD__ .
-                               ": reusing free connection from $oldDomain for $domain" );
-               } else {
+               }
+
+               if ( !$conn ) {
                        if ( !isset( $this->servers[$i] ) || !is_array( $this->servers[$i] ) ) {
                                throw new InvalidArgumentException( "No server with index '$i'." );
                        }
@@ -1265,6 +1281,11 @@ class LoadBalancer implements ILoadBalancer {
        }
 
        public function closeConnection( IDatabase $conn ) {
+               if ( $conn instanceof DBConnRef ) {
+                       // Avoid calling close() but still leaving the handle in the pool
+                       throw new RuntimeException( __METHOD__ . ': got DBConnRef instance.' );
+               }
+
                $serverIndex = $conn->getLBInfo( 'serverIndex' );
                foreach ( $this->conns as $type => $connsByServer ) {
                        if ( !isset( $connsByServer[$serverIndex] ) ) {
@@ -1379,7 +1400,7 @@ class LoadBalancer implements ILoadBalancer {
                $failures = [];
 
                /** @noinspection PhpUnusedLocalVariableInspection */
-               $scope = $this->getScopedPHPBehaviorForCommit(); // try to ignore client aborts
+               $scope = ScopedCallback::newScopedIgnoreUserAbort(); // try to ignore client aborts
 
                $restore = ( $this->trxRoundId !== false );
                $this->trxRoundId = false;
@@ -1897,7 +1918,15 @@ class LoadBalancer implements ILoadBalancer {
                $this->indexAliases = $aliases;
        }
 
+       /**
+        * @param string $prefix
+        * @deprecated Since 1.33
+        */
        public function setDomainPrefix( $prefix ) {
+               $this->setLocalDomainPrefix( $prefix );
+       }
+
+       public function setLocalDomainPrefix( $prefix ) {
                // Find connections to explicit foreign domains still marked as in-use...
                $domainsInUse = [];
                $this->forEachOpenConnection( function ( IDatabase $conn ) use ( &$domainsInUse ) {
@@ -1929,6 +1958,12 @@ class LoadBalancer implements ILoadBalancer {
                } );
        }
 
+       public function redefineLocalDomain( $domain ) {
+               $this->closeAll();
+
+               $this->setLocalDomain( DatabaseDomain::newFromId( $domain ) );
+       }
+
        /**
         * @param DatabaseDomain $domain
         */
@@ -1944,23 +1979,6 @@ class LoadBalancer implements ILoadBalancer {
                }
        }
 
-       /**
-        * Make PHP ignore user aborts/disconnects until the returned
-        * value leaves scope. This returns null and does nothing in CLI mode.
-        *
-        * @return ScopedCallback|null
-        */
-       final protected function getScopedPHPBehaviorForCommit() {
-               if ( PHP_SAPI != 'cli' ) { // https://bugs.php.net/bug.php?id=47540
-                       $old = ignore_user_abort( true ); // avoid half-finished operations
-                       return new ScopedCallback( function () use ( $old ) {
-                               ignore_user_abort( $old );
-                       } );
-               }
-
-               return null;
-       }
-
        function __destruct() {
                // Avoid connection leaks for sanity
                $this->disable();