class LoadBalancer implements ILoadBalancer {
/** @var array[] Map of (server index => server config array) */
private $mServers;
- /** @var Database[][][] Map of local/foreignUsed/foreignFree => server index => IDatabase[] */
+ /** @var Database[][][] Map of (connection category => server index => IDatabase[]) */
private $mConns;
/** @var float[] Map of (server index => weight) */
private $mLoads;
private $mGroupLoads;
/** @var bool Whether to disregard replica DB lag as a factor in replica DB selection */
private $mAllowLagged;
- /** @var integer Seconds to spend waiting on replica DB lag to resolve */
+ /** @var int Seconds to spend waiting on replica DB lag to resolve */
private $mWaitTimeout;
/** @var array The LoadMonitor configuration */
private $loadMonitorConfig;
private $chronProt;
/** @var BagOStuff */
private $srvCache;
- /** @var BagOStuff */
- private $memCache;
/** @var WANObjectCache */
private $wanCache;
/** @var object|string Class name or object With profileIn/profileOut methods */
/** @var Database DB connection object that caused a problem */
private $errorConnection;
- /** @var integer The generic (not query grouped) replica DB index (of $mServers) */
+ /** @var int The generic (not query grouped) replica DB index (of $mServers) */
private $mReadIndex;
/** @var bool|DBMasterPos False if not set */
private $mWaitForPos;
private $mLastError = 'Unknown error';
/** @var string|bool Reason the LB is read-only or false if not */
private $readOnlyReason = false;
- /** @var integer Total connections opened */
+ /** @var int Total connections opened */
private $connsOpened = 0;
/** @var string|bool String if a requested DBO_TRX transaction round is active */
private $trxRoundId = false;
/** @var callable Exception logger */
private $errorLogger;
- /** @var boolean */
+ /** @var bool */
private $disabled = false;
- /** @var boolean */
+ /** @var bool */
private $chronProtInitialized = false;
+ /** @var int */
+ private $maxLag = self::MAX_LAG_DEFAULT;
- /** @var integer Warn when this many connection are held */
+ /** @var int Warn when this many connection are held */
const CONN_HELD_WARN_THRESHOLD = 10;
- /** @var integer Default 'max lag' when unspecified */
+ /** @var int Default 'maxLag' when unspecified */
const MAX_LAG_DEFAULT = 10;
- /** @var integer Seconds to cache master server read-only status */
+ /** @var int Seconds to cache master server read-only status */
const TTL_CACHE_READONLY = 5;
const KEY_LOCAL = 'local';
const KEY_FOREIGN_FREE = 'foreignFree';
const KEY_FOREIGN_INUSE = 'foreignInUse';
+ const KEY_LOCAL_NOROUND = 'localAutoCommit';
+ const KEY_FOREIGN_FREE_NOROUND = 'foreignFreeAutoCommit';
+ const KEY_FOREIGN_INUSE_NOROUND = 'foreignInUseAutoCommit';
+
public function __construct( array $params ) {
if ( !isset( $params['servers'] ) ) {
throw new InvalidArgumentException( __CLASS__ . ': missing servers parameter' );
}
$this->mServers = $params['servers'];
+ foreach ( $this->mServers as $i => $server ) {
+ if ( $i == 0 ) {
+ $this->mServers[$i]['master'] = true;
+ } else {
+ $this->mServers[$i]['replica'] = true;
+ }
+ }
$this->localDomain = isset( $params['localDomain'] )
? DatabaseDomain::newFromId( $params['localDomain'] )
$this->mReadIndex = -1;
$this->mConns = [
+ // Connection were transaction rounds may be applied
self::KEY_LOCAL => [],
self::KEY_FOREIGN_INUSE => [],
- self::KEY_FOREIGN_FREE => []
+ self::KEY_FOREIGN_FREE => [],
+ // Auto-committing counterpart connections that ignore transaction rounds
+ self::KEY_LOCAL_NOROUND => [],
+ self::KEY_FOREIGN_INUSE_NOROUND => [],
+ self::KEY_FOREIGN_FREE_NOROUND => []
];
$this->mLoads = [];
$this->mWaitForPos = false;
$this->readOnlyReason = $params['readOnlyReason'];
}
+ if ( isset( $params['maxLag'] ) ) {
+ $this->maxLag = $params['maxLag'];
+ }
+
if ( isset( $params['loadMonitor'] ) ) {
$this->loadMonitorConfig = $params['loadMonitor'];
} else {
$this->loadMonitorConfig = [ 'class' => 'LoadMonitorNull' ];
}
+ $this->loadMonitorConfig += [ 'lagWarnThreshold' => $this->maxLag ];
foreach ( $params['servers'] as $i => $server ) {
$this->mLoads[$i] = $server['load'];
} else {
$this->srvCache = new EmptyBagOStuff();
}
- if ( isset( $params['memCache'] ) ) {
- $this->memCache = $params['memCache'];
- } else {
- $this->memCache = new EmptyBagOStuff();
- }
if ( isset( $params['wanCache'] ) ) {
$this->wanCache = $params['wanCache'];
} else {
}
$this->loadMonitor = new $class(
- $this, $this->srvCache, $this->memCache, $this->loadMonitorConfig );
+ $this, $this->srvCache, $this->wanCache, $this->loadMonitorConfig );
$this->loadMonitor->setLogger( $this->replLogger );
}
# How much lag this server nominally is allowed to have
$maxServerLag = isset( $this->mServers[$i]['max lag'] )
? $this->mServers[$i]['max lag']
- : self::MAX_LAG_DEFAULT; // default
+ : $this->maxLag; // default
# Constrain that futher by $maxLag argument
$maxServerLag = min( $maxServerLag, $maxLag );
"Server {host} is not replicating?", [ 'host' => $host ] );
unset( $loads[$i] );
} elseif ( $lag > $maxServerLag ) {
- $this->replLogger->warning(
+ $this->replLogger->info(
"Server {host} has {lag} seconds of lag (>= {maxlag})",
[ 'host' => $host, 'lag' => $lag, 'maxlag' => $maxServerLag ]
);
throw new InvalidArgumentException( "Empty server array given to LoadBalancer" );
}
- /** @var $i int|bool Index of selected server */
+ /** @var int|bool $i Index of selected server */
$i = false;
- /** @var $laggedReplicaMode bool Whether server is considered lagged */
+ /** @var bool $laggedReplicaMode Whether server is considered lagged */
$laggedReplicaMode = false;
// Quickly look through the available servers for a server that meets criteria...
public function getAnyOpenConnection( $i ) {
foreach ( $this->mConns as $connsByServer ) {
if ( !empty( $connsByServer[$i] ) ) {
- /** @var $serverConns IDatabase[] */
+ /** @var IDatabase[] $serverConns */
$serverConns = $connsByServer[$i];
return reset( $serverConns );
$knownReachedPos->hasReached( $this->mWaitForPos )
) {
$this->replLogger->debug( __METHOD__ .
- ": replica DB $server known to be caught up (pos >= $knownReachedPos)." );
+ ': replica DB {dbserver} known to be caught up (pos >= $knownReachedPos).',
+ [ 'dbserver' => $server ] );
return true;
}
$conn = $this->getAnyOpenConnection( $index );
if ( !$conn ) {
if ( !$open ) {
- $this->replLogger->debug( __METHOD__ . ": no connection open for $server" );
+ $this->replLogger->debug( __METHOD__ . ': no connection open for {dbserver}',
+ [ 'dbserver' => $server ] );
return false;
} else {
$conn = $this->openConnection( $index, self::DOMAIN_ANY );
if ( !$conn ) {
- $this->replLogger->warning( __METHOD__ . ": failed to connect to $server" );
+ $this->replLogger->warning( __METHOD__ . ': failed to connect to {dbserver}',
+ [ 'dbserver' => $server ] );
return false;
}
}
}
- $this->replLogger->info( __METHOD__ . ": Waiting for replica DB $server to catch up..." );
+ $this->replLogger->info( __METHOD__ . ': Waiting for replica DB {dbserver} to catch up...',
+ [ 'dbserver' => $server ] );
$timeout = $timeout ?: $this->mWaitTimeout;
$result = $conn->masterPosWait( $this->mWaitForPos, $timeout );
if ( $result == -1 || is_null( $result ) ) {
// Timed out waiting for replica DB, use master instead
$this->replLogger->warning(
- __METHOD__ . ": Timed out waiting on {host} pos {$this->mWaitForPos}",
- [ 'host' => $server ]
+ __METHOD__ . ': Timed out waiting on {host} pos {pos}',
+ [ 'host' => $server, 'pos' => $this->mWaitForPos ]
);
$ok = false;
} else {
return $ok;
}
- /**
- * @see ILoadBalancer::getConnection()
- *
- * @param int $i
- * @param array $groups
- * @param bool $domain
- * @return Database
- * @throws DBConnectionError
- */
- public function getConnection( $i, $groups = [], $domain = false ) {
+ public function getConnection( $i, $groups = [], $domain = false, $flags = 0 ) {
if ( $i === null || $i === false ) {
throw new InvalidArgumentException( 'Attempt to call ' . __METHOD__ .
' with invalid server index' );
}
# Now we have an explicit index into the servers array
- $conn = $this->openConnection( $i, $domain );
+ $conn = $this->openConnection( $i, $domain, $flags );
if ( !$conn ) {
// Throw an exception
$this->reportConnectionError();
return; // DBConnRef handle probably survived longer than the LoadBalancer
}
+ if ( $conn->getLBInfo( 'autoCommitOnly' ) ) {
+ $connFreeKey = self::KEY_FOREIGN_FREE_NOROUND;
+ $connInUseKey = self::KEY_FOREIGN_INUSE_NOROUND;
+ } else {
+ $connFreeKey = self::KEY_FOREIGN_FREE;
+ $connInUseKey = self::KEY_FOREIGN_INUSE;
+ }
+
$domain = $conn->getDomainID();
- if ( !isset( $this->mConns[self::KEY_FOREIGN_INUSE][$serverIndex][$domain] ) ) {
+ if ( !isset( $this->mConns[$connInUseKey][$serverIndex][$domain] ) ) {
throw new InvalidArgumentException( __METHOD__ .
": connection $serverIndex/$domain not found; it may have already been freed." );
- } elseif ( $this->mConns[self::KEY_FOREIGN_INUSE][$serverIndex][$domain] !== $conn ) {
+ } elseif ( $this->mConns[$connInUseKey][$serverIndex][$domain] !== $conn ) {
throw new InvalidArgumentException( __METHOD__ .
": connection $serverIndex/$domain mismatched; it may have already been freed." );
}
+
$conn->setLBInfo( 'foreignPoolRefCount', --$refCount );
if ( $refCount <= 0 ) {
- $this->mConns[self::KEY_FOREIGN_FREE][$serverIndex][$domain] = $conn;
- unset( $this->mConns[self::KEY_FOREIGN_INUSE][$serverIndex][$domain] );
- if ( !$this->mConns[self::KEY_FOREIGN_INUSE][$serverIndex] ) {
- unset( $this->mConns[ self::KEY_FOREIGN_INUSE ][$serverIndex] ); // clean up
+ $this->mConns[$connFreeKey][$serverIndex][$domain] = $conn;
+ unset( $this->mConns[$connInUseKey][$serverIndex][$domain] );
+ if ( !$this->mConns[$connInUseKey][$serverIndex] ) {
+ unset( $this->mConns[$connInUseKey][$serverIndex] ); // clean up
}
$this->connLogger->debug( __METHOD__ . ": freed connection $serverIndex/$domain" );
} else {
}
}
- public function getConnectionRef( $db, $groups = [], $domain = false ) {
+ public function getConnectionRef( $db, $groups = [], $domain = false, $flags = 0 ) {
$domain = ( $domain !== false ) ? $domain : $this->localDomain;
- return new DBConnRef( $this, $this->getConnection( $db, $groups, $domain ) );
+ return new DBConnRef( $this, $this->getConnection( $db, $groups, $domain, $flags ) );
}
- public function getLazyConnectionRef( $db, $groups = [], $domain = false ) {
+ public function getLazyConnectionRef( $db, $groups = [], $domain = false, $flags = 0 ) {
$domain = ( $domain !== false ) ? $domain : $this->localDomain;
- return new DBConnRef( $this, [ $db, $groups, $domain ] );
+ return new DBConnRef( $this, [ $db, $groups, $domain, $flags ] );
}
- public function getMaintenanceConnectionRef( $db, $groups = [], $domain = false ) {
+ public function getMaintenanceConnectionRef( $db, $groups = [], $domain = false, $flags = 0 ) {
$domain = ( $domain !== false ) ? $domain : $this->localDomain;
- return new MaintainableDBConnRef( $this, $this->getConnection( $db, $groups, $domain ) );
+ return new MaintainableDBConnRef(
+ $this, $this->getConnection( $db, $groups, $domain, $flags ) );
}
- /**
- * @see ILoadBalancer::openConnection()
- *
- * @param int $i
- * @param bool $domain
- * @return bool|Database
- * @throws DBAccessError
- */
- public function openConnection( $i, $domain = false ) {
+ public function openConnection( $i, $domain = false, $flags = 0 ) {
if ( $this->localDomain->equals( $domain ) || $domain === $this->localDomainIdAlias ) {
$domain = false; // local connection requested
}
$this->chronProt->initLB( $this );
}
+ // Check if an auto-commit connection is being requested. If so, it will not reuse the
+ // main set of DB connections but rather its own pool since:
+ // a) those are usually set to implicitly use transaction rounds via DBO_TRX
+ // b) those must support the use of explicit transaction rounds via beginMasterChanges()
+ $autoCommit = ( ( $flags & self::CONN_TRX_AUTO ) == self::CONN_TRX_AUTO );
+
if ( $domain !== false ) {
- $conn = $this->openForeignConnection( $i, $domain );
- } elseif ( isset( $this->mConns[self::KEY_LOCAL][$i][0] ) ) {
- $conn = $this->mConns[self::KEY_LOCAL][$i][0];
+ // Connection is to a foreign domain
+ $conn = $this->openForeignConnection( $i, $domain, $flags );
} else {
- if ( !isset( $this->mServers[$i] ) || !is_array( $this->mServers[$i] ) ) {
- throw new InvalidArgumentException( "No server with index '$i'." );
- }
- // Open a new connection
- $server = $this->mServers[$i];
- $server['serverIndex'] = $i;
- $conn = $this->reallyOpenConnection( $server, false );
- $serverName = $this->getServerName( $i );
- if ( $conn->isOpen() ) {
- $this->connLogger->debug( "Connected to database $i at '$serverName'." );
- $this->mConns[self::KEY_LOCAL][$i][0] = $conn;
+ // Connection is to the local domain
+ $connKey = $autoCommit ? self::KEY_LOCAL_NOROUND : self::KEY_LOCAL;
+ if ( isset( $this->mConns[$connKey][$i][0] ) ) {
+ $conn = $this->mConns[$connKey][$i][0];
} else {
- $this->connLogger->warning( "Failed to connect to database $i at '$serverName'." );
- $this->errorConnection = $conn;
- $conn = false;
+ if ( !isset( $this->mServers[$i] ) || !is_array( $this->mServers[$i] ) ) {
+ throw new InvalidArgumentException( "No server with index '$i'." );
+ }
+ // Open a new connection
+ $server = $this->mServers[$i];
+ $server['serverIndex'] = $i;
+ $server['autoCommitOnly'] = $autoCommit;
+ $conn = $this->reallyOpenConnection( $server, false );
+ $host = $this->getServerName( $i );
+ if ( $conn->isOpen() ) {
+ $this->connLogger->debug( "Connected to database $i at '$host'." );
+ $this->mConns[$connKey][$i][0] = $conn;
+ } else {
+ $this->connLogger->warning( "Failed to connect to database $i at '$host'." );
+ $this->errorConnection = $conn;
+ $conn = false;
+ }
}
}
$conn = false;
}
+ if ( $autoCommit && $conn instanceof IDatabase ) {
+ $conn->clearFlag( $conn::DBO_TRX ); // auto-commit mode
+ }
+
return $conn;
}
*
* @param int $i Server index
* @param string $domain Domain ID to open
+ * @param int $flags Class CONN_* constant bitfield
* @return Database
*/
- private function openForeignConnection( $i, $domain ) {
+ private function openForeignConnection( $i, $domain, $flags = 0 ) {
$domainInstance = DatabaseDomain::newFromId( $domain );
$dbName = $domainInstance->getDatabase();
$prefix = $domainInstance->getTablePrefix();
+ $autoCommit = ( ( $flags & self::CONN_TRX_AUTO ) == self::CONN_TRX_AUTO );
- if ( isset( $this->mConns[self::KEY_FOREIGN_INUSE][$i][$domain] ) ) {
- // Reuse an in-use connection for the same domain that is not in-use
- $conn = $this->mConns[self::KEY_FOREIGN_INUSE][$i][$domain];
+ if ( $autoCommit ) {
+ $connFreeKey = self::KEY_FOREIGN_FREE_NOROUND;
+ $connInUseKey = self::KEY_FOREIGN_INUSE_NOROUND;
+ } else {
+ $connFreeKey = self::KEY_FOREIGN_FREE;
+ $connInUseKey = self::KEY_FOREIGN_INUSE;
+ }
+
+ if ( isset( $this->mConns[$connInUseKey][$i][$domain] ) ) {
+ // Reuse an in-use connection for the same domain
+ $conn = $this->mConns[$connInUseKey][$i][$domain];
$this->connLogger->debug( __METHOD__ . ": reusing connection $i/$domain" );
- } elseif ( isset( $this->mConns[self::KEY_FOREIGN_FREE][$i][$domain] ) ) {
- // Reuse a free connection for the same domain that is not in-use
- $conn = $this->mConns[self::KEY_FOREIGN_FREE][$i][$domain];
- unset( $this->mConns[self::KEY_FOREIGN_FREE][$i][$domain] );
- $this->mConns[self::KEY_FOREIGN_INUSE][$i][$domain] = $conn;
+ } elseif ( isset( $this->mConns[$connFreeKey][$i][$domain] ) ) {
+ // Reuse a free connection for the same domain
+ $conn = $this->mConns[$connFreeKey][$i][$domain];
+ unset( $this->mConns[$connFreeKey][$i][$domain] );
+ $this->mConns[$connInUseKey][$i][$domain] = $conn;
$this->connLogger->debug( __METHOD__ . ": reusing free connection $i/$domain" );
- } elseif ( !empty( $this->mConns[self::KEY_FOREIGN_FREE][$i] ) ) {
- // Reuse a connection from another domain
- $conn = reset( $this->mConns[self::KEY_FOREIGN_FREE][$i] );
- $oldDomain = key( $this->mConns[self::KEY_FOREIGN_FREE][$i] );
+ } elseif ( !empty( $this->mConns[$connFreeKey][$i] ) ) {
+ // Reuse a free connection from another domain
+ $conn = reset( $this->mConns[$connFreeKey][$i] );
+ $oldDomain = key( $this->mConns[$connFreeKey][$i] );
// The empty string as a DB name means "don't care".
// DatabaseMysqlBase::open() already handle this on connection.
if ( strlen( $dbName ) && !$conn->selectDB( $dbName ) ) {
$conn = false;
} else {
$conn->tablePrefix( $prefix );
- unset( $this->mConns[self::KEY_FOREIGN_FREE][$i][$oldDomain] );
- $this->mConns[self::KEY_FOREIGN_INUSE][$i][$domain] = $conn;
+ unset( $this->mConns[$connFreeKey][$i][$oldDomain] );
+ $this->mConns[$connInUseKey][$i][$domain] = $conn;
$this->connLogger->debug( __METHOD__ .
": reusing free connection from $oldDomain for $domain" );
}
$server['serverIndex'] = $i;
$server['foreignPoolRefCount'] = 0;
$server['foreign'] = true;
+ $server['autoCommitOnly'] = $autoCommit;
$conn = $this->reallyOpenConnection( $server, $dbName );
if ( !$conn->isOpen() ) {
$this->connLogger->warning( __METHOD__ . ": connection error for $i/$domain" );
$conn = false;
} else {
$conn->tablePrefix( $prefix );
- $this->mConns[self::KEY_FOREIGN_INUSE][$i][$domain] = $conn;
+ $this->mConns[$connInUseKey][$i][$domain] = $conn;
$this->connLogger->debug( __METHOD__ . ": opened new connection for $i/$domain" );
}
}
return ( $name != '' ) ? $name : 'localhost';
}
+ public function getServerType( $i ) {
+ return isset( $this->mServers[$i]['type'] ) ? $this->mServers[$i]['type'] : 'unknown';
+ }
+
/**
* @deprecated Since 1.30, no alternative
*/
$this->mConns = [
self::KEY_LOCAL => [],
- self::KEY_FOREIGN_FREE => [],
self::KEY_FOREIGN_INUSE => [],
+ self::KEY_FOREIGN_FREE => [],
+ self::KEY_LOCAL_NOROUND => [],
+ self::KEY_FOREIGN_INUSE_NOROUND => [],
+ self::KEY_FOREIGN_FREE_NOROUND => []
];
$this->connsOpened = 0;
}
* @param IDatabase $conn
*/
private function applyTransactionRoundFlags( IDatabase $conn ) {
+ if ( $conn->getLBInfo( 'autoCommitOnly' ) ) {
+ return; // transaction rounds do not apply to these connections
+ }
+
if ( $conn->getFlag( $conn::DBO_DEFAULT ) ) {
// DBO_TRX is controlled entirely by CLI mode presence with DBO_DEFAULT.
// Force DBO_TRX even in CLI mode since a commit round is expected soon.
* @param IDatabase $conn
*/
private function undoTransactionRoundFlags( IDatabase $conn ) {
+ if ( $conn->getLBInfo( 'autoCommitOnly' ) ) {
+ return; // transaction rounds do not apply to these connections
+ }
+
if ( $conn->getFlag( $conn::DBO_DEFAULT ) ) {
$conn->restoreFlags( $conn::RESTORE_PRIOR );
}
if ( $pos instanceof DBMasterPos ) {
$result = $conn->masterPosWait( $pos, $timeout );
if ( $result == -1 || is_null( $result ) ) {
- $msg = __METHOD__ . ": Timed out waiting on {$conn->getServer()} pos {$pos}";
- $this->replLogger->warning( "$msg" );
+ $msg = __METHOD__ . ': Timed out waiting on {host} pos {pos}';
+ $this->replLogger->warning( $msg,
+ [ 'host' => $conn->getServer(), 'pos' => $pos ] );
$ok = false;
} else {
- $this->replLogger->info( __METHOD__ . ": Done" );
+ $this->replLogger->info( __METHOD__ . ': Done' );
$ok = true;
}
} else {
$ok = false; // something is misconfigured
- $this->replLogger->error( "Could not get master pos for {$conn->getServer()}." );
+ $this->replLogger->error( 'Could not get master pos for {host}',
+ [ 'host' => $conn->getServer() ] );
}
return $ok;