Update to MediaWiki 1.25.1

17 files changed, 1058 insertions, 885 deletions

diff --git a/includes/db/Database.php b/includes/db/Database.php
index 9b783a99..0c0248da 100644
--- a/includes/db/Database.php
+++ b/includes/db/Database.php
@@ -26,186 +26,6 @@
  */
 
 /**
- * Base interface for all DBMS-specific code. At a bare minimum, all of the
- * following must be implemented to support MediaWiki
- *
- * @file
- * @ingroup Database
- */
-interface DatabaseType {
-	/**
-	 * Get the type of the DBMS, as it appears in $wgDBtype.
-	 *
-	 * @return string
-	 */
-	function getType();
-
-	/**
-	 * Open a connection to the database. Usually aborts on failure
-	 *
-	 * @param string $server Database server host
-	 * @param string $user Database user name
-	 * @param string $password Database user password
-	 * @param string $dbName Database name
-	 * @return bool
-	 * @throws DBConnectionError
-	 */
-	function open( $server, $user, $password, $dbName );
-
-	/**
-	 * Fetch the next row from the given result object, in object form.
-	 * Fields can be retrieved with $row->fieldname, with fields acting like
-	 * member variables.
-	 * If no more rows are available, false is returned.
-	 *
-	 * @param ResultWrapper|stdClass $res Object as returned from DatabaseBase::query(), etc.
-	 * @return stdClass|bool
-	 * @throws DBUnexpectedError Thrown if the database returns an error
-	 */
-	function fetchObject( $res );
-
-	/**
-	 * Fetch the next row from the given result object, in associative array
-	 * form. Fields are retrieved with $row['fieldname'].
-	 * If no more rows are available, false is returned.
-	 *
-	 * @param ResultWrapper $res Result object as returned from DatabaseBase::query(), etc.
-	 * @return array|bool
-	 * @throws DBUnexpectedError Thrown if the database returns an error
-	 */
-	function fetchRow( $res );
-
-	/**
-	 * Get the number of rows in a result object
-	 *
-	 * @param mixed $res A SQL result
-	 * @return int
-	 */
-	function numRows( $res );
-
-	/**
-	 * Get the number of fields in a result object
-	 * @see http://www.php.net/mysql_num_fields
-	 *
-	 * @param mixed $res A SQL result
-	 * @return int
-	 */
-	function numFields( $res );
-
-	/**
-	 * Get a field name in a result object
-	 * @see http://www.php.net/mysql_field_name
-	 *
-	 * @param mixed $res A SQL result
-	 * @param int $n
-	 * @return string
-	 */
-	function fieldName( $res, $n );
-
-	/**
-	 * Get the inserted value of an auto-increment row
-	 *
-	 * The value inserted should be fetched from nextSequenceValue()
-	 *
-	 * Example:
-	 * $id = $dbw->nextSequenceValue( 'page_page_id_seq' );
-	 * $dbw->insert( 'page', array( 'page_id' => $id ) );
-	 * $id = $dbw->insertId();
-	 *
-	 * @return int
-	 */
-	function insertId();
-
-	/**
-	 * Change the position of the cursor in a result object
-	 * @see http://www.php.net/mysql_data_seek
-	 *
-	 * @param mixed $res A SQL result
-	 * @param int $row
-	 */
-	function dataSeek( $res, $row );
-
-	/**
-	 * Get the last error number
-	 * @see http://www.php.net/mysql_errno
-	 *
-	 * @return int
-	 */
-	function lastErrno();
-
-	/**
-	 * Get a description of the last error
-	 * @see http://www.php.net/mysql_error
-	 *
-	 * @return string
-	 */
-	function lastError();
-
-	/**
-	 * mysql_fetch_field() wrapper
-	 * Returns false if the field doesn't exist
-	 *
-	 * @param string $table Table name
-	 * @param string $field Field name
-	 *
-	 * @return Field
-	 */
-	function fieldInfo( $table, $field );
-
-	/**
-	 * Get information about an index into an object
-	 * @param string $table Table name
-	 * @param string $index Index name
-	 * @param string $fname Calling function name
-	 * @return mixed Database-specific index description class or false if the index does not exist
-	 */
-	function indexInfo( $table, $index, $fname = __METHOD__ );
-
-	/**
-	 * Get the number of rows affected by the last write query
-	 * @see http://www.php.net/mysql_affected_rows
-	 *
-	 * @return int
-	 */
-	function affectedRows();
-
-	/**
-	 * Wrapper for addslashes()
-	 *
-	 * @param string $s String to be slashed.
-	 * @return string Slashed string.
-	 */
-	function strencode( $s );
-
-	/**
-	 * Returns a wikitext link to the DB's website, e.g.,
-	 *   return "[http://www.mysql.com/ MySQL]";
-	 * Should at least contain plain text, if for some reason
-	 * your database has no website.
-	 *
-	 * @return string Wikitext of a link to the server software's web site
-	 */
-	function getSoftwareLink();
-
-	/**
-	 * A string describing the current software version, like from
-	 * mysql_get_server_info().
-	 *
-	 * @return string Version information from the database server.
-	 */
-	function getServerVersion();
-
-	/**
-	 * A string describing the current software version, and possibly
-	 * other details in a user-friendly way. Will be listed on Special:Version, etc.
-	 * Use getServerVersion() to get machine-friendly information.
-	 *
-	 * @return string Version information from the database server
-	 */
-	function getServerInfo();
-}
-
-/**
  * Interface for classes that implement or wrap DatabaseBase
  * @ingroup Database
  */
@@ -216,7 +36,7 @@ interface IDatabase {
  * Database abstraction object
  * @ingroup Database
  */
-abstract class DatabaseBase implements IDatabase, DatabaseType {
+abstract class DatabaseBase implements IDatabase {
 	/** Number of times to re-try an operation in case of deadlock */
 	const DEADLOCK_TRIES = 4;
 
@@ -226,10 +46,6 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	/** Maximum time to wait before retry */
 	const DEADLOCK_DELAY_MAX = 1500000;
 
-# ------------------------------------------------------------------------------
-# Variables
-# ------------------------------------------------------------------------------
-
 	protected $mLastQuery = '';
 	protected $mDoneWrites = false;
 	protected $mPHPError = false;
@@ -272,10 +88,21 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 * Either a short hexidecimal string if a transaction is active or ""
 	 *
 	 * @var string
+	 * @see DatabaseBase::mTrxLevel
 	 */
 	protected $mTrxShortId = '';
 
 	/**
+	 * The UNIX time that the transaction started. Callers can assume that if
+	 * snapshot isolation is used, then the data is *at least* up to date to that
+	 * point (possibly more up-to-date since the first SELECT defines the snapshot).
+	 *
+	 * @var float|null
+	 * @see DatabaseBase::mTrxLevel
+	 */
+	private $mTrxTimestamp = null;
+
+	/**
 	 * Remembers the function name given for starting the most recent transaction via begin().
 	 * Used to provide additional context for error reporting.
 	 *
@@ -326,10 +153,8 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 */
 	protected $allViews = null;
 
-# ------------------------------------------------------------------------------
-# Accessors
-# ------------------------------------------------------------------------------
-	# These optionally set a variable and return the previous state
+	/** @var TransactionProfiler */
+	protected $trxProfiler;
 
 	/**
 	 * A string describing the current software version, and possibly
@@ -420,6 +245,19 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	}
 
 	/**
+	 * Get the UNIX timestamp of the time that the transaction was established
+	 *
+	 * This can be used to reason about the staleness of SELECT data
+	 * in REPEATABLE-READ transaction isolation level.
+	 *
+	 * @return float|null Returns null if there is not active transaction
+	 * @since 1.25
+	 */
+	public function trxTimestamp() {
+		return $this->mTrxLevel ? $this->mTrxTimestamp : null;
+	}
+
+	/**
 	 * Get/set the number of errors logged. Only useful when errors are ignored
 	 * @param int $count The count to set, or omitted to leave it unchanged.
 	 * @return int The error count
@@ -511,6 +349,15 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	}
 
 	/**
+	 * @return TransactionProfiler
+	 */
+	protected function getTransactionProfiler() {
+		return $this->trxProfiler
+			? $this->trxProfiler
+			: Profiler::instance()->getTransactionProfiler();
+	}
+
+	/**
 	 * Returns true if this database supports (and uses) cascading deletes
 	 *
 	 * @return bool
@@ -744,9 +591,167 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		return $this->getSqlFilePath( 'update-keys.sql' );
 	}
 
-# ------------------------------------------------------------------------------
-# Other functions
-# ------------------------------------------------------------------------------
+	/**
+	 * Get the type of the DBMS, as it appears in $wgDBtype.
+	 *
+	 * @return string
+	 */
+	abstract function getType();
+
+	/**
+	 * Open a connection to the database. Usually aborts on failure
+	 *
+	 * @param string $server Database server host
+	 * @param string $user Database user name
+	 * @param string $password Database user password
+	 * @param string $dbName Database name
+	 * @return bool
+	 * @throws DBConnectionError
+	 */
+	abstract function open( $server, $user, $password, $dbName );
+
+	/**
+	 * Fetch the next row from the given result object, in object form.
+	 * Fields can be retrieved with $row->fieldname, with fields acting like
+	 * member variables.
+	 * If no more rows are available, false is returned.
+	 *
+	 * @param ResultWrapper|stdClass $res Object as returned from DatabaseBase::query(), etc.
+	 * @return stdClass|bool
+	 * @throws DBUnexpectedError Thrown if the database returns an error
+	 */
+	abstract function fetchObject( $res );
+
+	/**
+	 * Fetch the next row from the given result object, in associative array
+	 * form. Fields are retrieved with $row['fieldname'].
+	 * If no more rows are available, false is returned.
+	 *
+	 * @param ResultWrapper $res Result object as returned from DatabaseBase::query(), etc.
+	 * @return array|bool
+	 * @throws DBUnexpectedError Thrown if the database returns an error
+	 */
+	abstract function fetchRow( $res );
+
+	/**
+	 * Get the number of rows in a result object
+	 *
+	 * @param mixed $res A SQL result
+	 * @return int
+	 */
+	abstract function numRows( $res );
+
+	/**
+	 * Get the number of fields in a result object
+	 * @see http://www.php.net/mysql_num_fields
+	 *
+	 * @param mixed $res A SQL result
+	 * @return int
+	 */
+	abstract function numFields( $res );
+
+	/**
+	 * Get a field name in a result object
+	 * @see http://www.php.net/mysql_field_name
+	 *
+	 * @param mixed $res A SQL result
+	 * @param int $n
+	 * @return string
+	 */
+	abstract function fieldName( $res, $n );
+
+	/**
+	 * Get the inserted value of an auto-increment row
+	 *
+	 * The value inserted should be fetched from nextSequenceValue()
+	 *
+	 * Example:
+	 * $id = $dbw->nextSequenceValue( 'page_page_id_seq' );
+	 * $dbw->insert( 'page', array( 'page_id' => $id ) );
+	 * $id = $dbw->insertId();
+	 *
+	 * @return int
+	 */
+	abstract function insertId();
+
+	/**
+	 * Change the position of the cursor in a result object
+	 * @see http://www.php.net/mysql_data_seek
+	 *
+	 * @param mixed $res A SQL result
+	 * @param int $row
+	 */
+	abstract function dataSeek( $res, $row );
+
+	/**
+	 * Get the last error number
+	 * @see http://www.php.net/mysql_errno
+	 *
+	 * @return int
+	 */
+	abstract function lastErrno();
+
+	/**
+	 * Get a description of the last error
+	 * @see http://www.php.net/mysql_error
+	 *
+	 * @return string
+	 */
+	abstract function lastError();
+
+	/**
+	 * mysql_fetch_field() wrapper
+	 * Returns false if the field doesn't exist
+	 *
+	 * @param string $table Table name
+	 * @param string $field Field name
+	 *
+	 * @return Field
+	 */
+	abstract function fieldInfo( $table, $field );
+
+	/**
+	 * Get information about an index into an object
+	 * @param string $table Table name
+	 * @param string $index Index name
+	 * @param string $fname Calling function name
+	 * @return mixed Database-specific index description class or false if the index does not exist
+	 */
+	abstract function indexInfo( $table, $index, $fname = __METHOD__ );
+
+	/**
+	 * Get the number of rows affected by the last write query
+	 * @see http://www.php.net/mysql_affected_rows
+	 *
+	 * @return int
+	 */
+	abstract function affectedRows();
+
+	/**
+	 * Wrapper for addslashes()
+	 *
+	 * @param string $s String to be slashed.
+	 * @return string Slashed string.
+	 */
+	abstract function strencode( $s );
+
+	/**
+	 * Returns a wikitext link to the DB's website, e.g.,
+	 *   return "[http://www.mysql.com/ MySQL]";
+	 * Should at least contain plain text, if for some reason
+	 * your database has no website.
+	 *
+	 * @return string Wikitext of a link to the server software's web site
+	 */
+	abstract function getSoftwareLink();
+
+	/**
+	 * A string describing the current software version, like from
+	 * mysql_get_server_info().
+	 *
+	 * @return string Version information from the database server.
+	 */
+	abstract function getServerVersion();
 
 	/**
 	 * Constructor.
@@ -760,32 +765,19 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 *
 	 * @param array $params Parameters passed from DatabaseBase::factory()
 	 */
-	function __construct( $params = null ) {
+	function __construct( array $params ) {
 		global $wgDBprefix, $wgDBmwschema, $wgCommandLineMode, $wgDebugDBTransactions;
 
 		$this->mTrxAtomicLevels = new SplStack;
 
-		if ( is_array( $params ) ) { // MW 1.22
-			$server = $params['host'];
-			$user = $params['user'];
-			$password = $params['password'];
-			$dbName = $params['dbname'];
-			$flags = $params['flags'];
-			$tablePrefix = $params['tablePrefix'];
-			$schema = $params['schema'];
-			$foreign = $params['foreign'];
-		} else { // legacy calling pattern
-			wfDeprecated( __METHOD__ . " method called without parameter array.", "1.23" );
-			$args = func_get_args();
-			$server = isset( $args[0] ) ? $args[0] : false;
-			$user = isset( $args[1] ) ? $args[1] : false;
-			$password = isset( $args[2] ) ? $args[2] : false;
-			$dbName = isset( $args[3] ) ? $args[3] : false;
-			$flags = isset( $args[4] ) ? $args[4] : 0;
-			$tablePrefix = isset( $args[5] ) ? $args[5] : 'get from global';
-			$schema = 'get from global';
-			$foreign = isset( $args[6] ) ? $args[6] : false;
-		}
+		$server = $params['host'];
+		$user = $params['user'];
+		$password = $params['password'];
+		$dbName = $params['dbname'];
+		$flags = $params['flags'];
+		$tablePrefix = $params['tablePrefix'];
+		$schema = $params['schema'];
+		$foreign = $params['foreign'];
 
 		$this->mFlags = $flags;
 		if ( $this->mFlags & DBO_DEFAULT ) {
@@ -818,6 +810,10 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 
 		$this->mForeign = $foreign;
 
+		if ( isset( $params['trxProfiler'] ) ) {
+			$this->trxProfiler = $params['trxProfiler']; // override
+		}
+
 		if ( $user ) {
 			$this->open( $server, $user, $password, $dbName );
 		}
@@ -905,18 +901,17 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 
 		$class = 'Database' . ucfirst( $driver );
 		if ( class_exists( $class ) && is_subclass_of( $class, 'DatabaseBase' ) ) {
-			$params = array(
-				'host' => isset( $p['host'] ) ? $p['host'] : false,
-				'user' => isset( $p['user'] ) ? $p['user'] : false,
-				'password' => isset( $p['password'] ) ? $p['password'] : false,
-				'dbname' => isset( $p['dbname'] ) ? $p['dbname'] : false,
-				'flags' => isset( $p['flags'] ) ? $p['flags'] : 0,
-				'tablePrefix' => isset( $p['tablePrefix'] ) ? $p['tablePrefix'] : 'get from global',
-				'schema' => isset( $p['schema'] ) ? $p['schema'] : $defaultSchemas[$dbType],
-				'foreign' => isset( $p['foreign'] ) ? $p['foreign'] : false
-			);
-
-			return new $class( $params );
+			// Resolve some defaults for b/c
+			$p['host'] = isset( $p['host'] ) ? $p['host'] : false;
+			$p['user'] = isset( $p['user'] ) ? $p['user'] : false;
+			$p['password'] = isset( $p['password'] ) ? $p['password'] : false;
+			$p['dbname'] = isset( $p['dbname'] ) ? $p['dbname'] : false;
+			$p['flags'] = isset( $p['flags'] ) ? $p['flags'] : 0;
+			$p['tablePrefix'] = isset( $p['tablePrefix'] ) ? $p['tablePrefix'] : 'get from global';
+			$p['schema'] = isset( $p['schema'] ) ? $p['schema'] : $defaultSchemas[$dbType];
+			$p['foreign'] = isset( $p['foreign'] ) ? $p['foreign'] : false;
+
+			return new $class( $p );
 		} else {
 			return null;
 		}
@@ -955,6 +950,23 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	}
 
 	/**
+	 * Create a log context to pass to wfLogDBError or other logging functions.
+	 *
+	 * @param array $extras Additional data to add to context
+	 * @return array
+	 */
+	protected function getLogContext( array $extras = array() ) {
+		return array_merge(
+			array(
+				'db_server' => $this->mServer,
+				'db_name' => $this->mDBname,
+				'db_user' => $this->mUser,
+			),
+			$extras
+		);
+	}
+
+	/**
 	 * Closes a database connection.
 	 * if it is open : commits any open transactions
 	 *
@@ -1027,6 +1039,20 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	}
 
 	/**
+	 * Determine whether a SQL statement is sensitive to isolation level.
+	 * A SQL statement is considered transactable if its result could vary
+	 * depending on the transaction isolation level. Operational commands
+	 * such as 'SET' and 'SHOW' are not considered to be transactable.
+	 *
+	 * @param string $sql
+	 * @return bool
+	 */
+	public function isTransactableQuery( $sql ) {
+		$verb = substr( $sql, 0, strcspn( $sql, " \t\r\n" ) );
+		return !in_array( $verb, array( 'BEGIN', 'COMMIT', 'ROLLBACK', 'SHOW', 'SET' ) );
+	}
+
+	/**
 	 * Run an SQL query and return the result. Normally throws a DBQueryError
 	 * on failure. If errors are ignored, returns false instead.
 	 *
@@ -1052,9 +1078,14 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		global $wgUser, $wgDebugDBTransactions, $wgDebugDumpSqlLength;
 
 		$this->mLastQuery = $sql;
-		if ( $this->isWriteQuery( $sql ) ) {
+
+		$isWriteQuery = $this->isWriteQuery( $sql );
+		if ( $isWriteQuery ) {
+			if ( !$this->mDoneWrites ) {
+				wfDebug( __METHOD__ . ': Writes done: ' .
+					DatabaseBase::generalizeSQL( $sql ) . "\n" );
+			}
 			# Set a flag indicating that writes have been done
-			wfDebug( __METHOD__ . ': Writes done: ' . DatabaseBase::generalizeSQL( $sql ) . "\n" );
 			$this->mDoneWrites = microtime( true );
 		}
 
@@ -1073,50 +1104,38 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		// Or, for one-word queries (like "BEGIN" or COMMIT") add it to the end (bug 42598)
 		$commentedSql = preg_replace( '/\s|$/', " /* $fname $userName */ ", $sql, 1 );
 
-		# If DBO_TRX is set, start a transaction
-		if ( ( $this->mFlags & DBO_TRX ) && !$this->mTrxLevel &&
-			$sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK'
-		) {
-			# Avoid establishing transactions for SHOW and SET statements too -
-			# that would delay transaction initializations to once connection
-			# is really used by application
-			$sqlstart = substr( $sql, 0, 10 ); // very much worth it, benchmark certified(tm)
-			if ( strpos( $sqlstart, "SHOW " ) !== 0 && strpos( $sqlstart, "SET " ) !== 0 ) {
-				if ( $wgDebugDBTransactions ) {
-					wfDebug( "Implicit transaction start.\n" );
-				}
-				$this->begin( __METHOD__ . " ($fname)" );
-				$this->mTrxAutomatic = true;
+		if ( !$this->mTrxLevel && $this->getFlag( DBO_TRX ) && $this->isTransactableQuery( $sql ) ) {
+			if ( $wgDebugDBTransactions ) {
+				wfDebug( "Implicit transaction start.\n" );
 			}
+			$this->begin( __METHOD__ . " ($fname)" );
+			$this->mTrxAutomatic = true;
 		}
 
 		# Keep track of whether the transaction has write queries pending
-		if ( $this->mTrxLevel && !$this->mTrxDoneWrites && $this->isWriteQuery( $sql ) ) {
+		if ( $this->mTrxLevel && !$this->mTrxDoneWrites && $isWriteQuery ) {
 			$this->mTrxDoneWrites = true;
-			Profiler::instance()->transactionWritingIn(
+			$this->getTransactionProfiler()->transactionWritingIn(
 				$this->mServer, $this->mDBname, $this->mTrxShortId );
 		}
 
-		$queryProf = '';
-		$totalProf = '';
 		$isMaster = !is_null( $this->getLBInfo( 'master' ) );
+		# generalizeSQL will probably cut down the query to reasonable
+		# logging size most of the time. The substr is really just a sanity check.
+		if ( $isMaster ) {
+			$queryProf = 'query-m: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
+			$totalProf = 'DatabaseBase::query-master';
+		} else {
+			$queryProf = 'query: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
+			$totalProf = 'DatabaseBase::query';
+		}
+		# Include query transaction state
+		$queryProf .= $this->mTrxShortId ? " [TRX#{$this->mTrxShortId}]" : "";
 
-		if ( !Profiler::instance()->isStub() ) {
-			# generalizeSQL will probably cut down the query to reasonable
-			# logging size most of the time. The substr is really just a sanity check.
-			if ( $isMaster ) {
-				$queryProf = 'query-m: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
-				$totalProf = 'DatabaseBase::query-master';
-			} else {
-				$queryProf = 'query: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
-				$totalProf = 'DatabaseBase::query';
-			}
-			# Include query transaction state
-			$queryProf .= $this->mTrxShortId ? " [TRX#{$this->mTrxShortId}]" : "";
-
-			$trx = $this->mTrxLevel ? 'TRX=yes' : 'TRX=no';
-			wfProfileIn( $totalProf );
-			wfProfileIn( $queryProf );
+		$profiler = Profiler::instance();
+		if ( !$profiler instanceof ProfilerStub ) {
+			$totalProfSection = $profiler->scopedProfileIn( $totalProf );
+			$queryProfSection = $profiler->scopedProfileIn( $queryProf );
 		}
 
 		if ( $this->debug() ) {
@@ -1139,7 +1158,11 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		}
 
 		# Do the query and handle errors
+		$startTime = microtime( true );
 		$ret = $this->doQuery( $commentedSql );
+		# Log the query time and feed it into the DB trx profiler
+		$this->getTransactionProfiler()->recordQueryCompletion(
+			$queryProf, $startTime, $isWriteQuery, $this->affectedRows() );
 
 		MWDebug::queryTime( $queryId );
 
@@ -1155,23 +1178,22 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 			$lastError = $this->lastError();
 			$lastErrno = $this->lastErrno();
 			if ( $this->ping() ) {
-				global $wgRequestTime;
 				wfDebug( "Reconnected\n" );
-				$sqlx = $wgDebugDumpSqlLength ? substr( $commentedSql, 0, $wgDebugDumpSqlLength )
-					: $commentedSql;
-				$sqlx = strtr( $sqlx, "\t\n", '  ' );
-				$elapsed = round( microtime( true ) - $wgRequestTime, 3 );
-				if ( $elapsed < 300 ) {
-					# Not a database error to lose a transaction after a minute or two
-					wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx" );
-				}
+				$server = $this->getServer();
+				$msg = __METHOD__ . ": lost connection to $server; reconnected";
+				wfDebugLog( 'DBPerformance', "$msg:\n" . wfBacktrace( true ) );
+
 				if ( $hadTrx ) {
 					# Leave $ret as false and let an error be reported.
 					# Callers may catch the exception and continue to use the DB.
 					$this->reportQueryError( $lastError, $lastErrno, $sql, $fname, $tempIgnore );
 				} else {
 					# Should be safe to silently retry (no trx and thus no callbacks)
+					$startTime = microtime( true );
 					$ret = $this->doQuery( $commentedSql );
+					# Log the query time and feed it into the DB trx profiler
+					$this->getTransactionProfiler()->recordQueryCompletion(
+						$queryProf, $startTime, $isWriteQuery, $this->affectedRows() );
 				}
 			} else {
 				wfDebug( "Failed\n" );
@@ -1179,15 +1201,17 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		}
 
 		if ( false === $ret ) {
-			$this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
+			$this->reportQueryError(
+				$this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 		}
 
-		if ( !Profiler::instance()->isStub() ) {
-			wfProfileOut( $queryProf );
-			wfProfileOut( $totalProf );
-		}
+		$res = $this->resultObject( $ret );
+
+		// Destroy profile sections in the opposite order to their creation
+		$queryProfSection = false;
+		$totalProfSection = false;
 
-		return $this->resultObject( $ret );
+		return $res;
 	}
 
 	/**
@@ -1202,16 +1226,22 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 * @throws DBQueryError
 	 */
 	public function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
-		# Ignore errors during error handling to avoid infinite recursion
-		$ignore = $this->ignoreErrors( true );
 		++$this->mErrorCount;
 
-		if ( $ignore || $tempIgnore ) {
+		if ( $this->ignoreErrors() || $tempIgnore ) {
 			wfDebug( "SQL ERROR (ignored): $error\n" );
-			$this->ignoreErrors( $ignore );
 		} else {
 			$sql1line = mb_substr( str_replace( "\n", "\\n", $sql ), 0, 5 * 1024 );
-			wfLogDBError( "$fname\t{$this->mServer}\t$errno\t$error\t$sql1line" );
+			wfLogDBError(
+				"{fname}\t{db_server}\t{errno}\t{error}\t{sql1line}",
+				$this->getLogContext( array(
+					'method' => __METHOD__,
+					'errno' => $errno,
+					'error' => $error,
+					'sql1line' => $sql1line,
+					'fname' => $fname,
+				) )
+			);
 			wfDebug( "SQL ERROR: " . $error . "\n" );
 			throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 		}
@@ -1348,9 +1378,13 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 *
 	 * @return bool|mixed The value from the field, or false on failure.
 	 */
-	public function selectField( $table, $var, $cond = '', $fname = __METHOD__,
-		$options = array()
+	public function selectField(
+		$table, $var, $cond = '', $fname = __METHOD__, $options = array()
 	) {
+		if ( $var === '*' ) { // sanity
+			throw new DBUnexpectedError( $this, "Cannot use a * field: got '$var'" );
+		}
+
 		if ( !is_array( $options ) ) {
 			$options = array( $options );
 		}
@@ -1358,7 +1392,6 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		$options['LIMIT'] = 1;
 
 		$res = $this->select( $table, $var, $cond, $fname, $options );
-
 		if ( $res === false || !$this->numRows( $res ) ) {
 			return false;
 		}
@@ -1373,6 +1406,48 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	}
 
 	/**
+	 * A SELECT wrapper which returns a list of single field values from result rows.
+	 *
+	 * Usually throws a DBQueryError on failure. If errors are explicitly
+	 * ignored, returns false on failure.
+	 *
+	 * If no result rows are returned from the query, false is returned.
+	 *
+	 * @param string|array $table Table name. See DatabaseBase::select() for details.
+	 * @param string $var The field name to select. This must be a valid SQL
+	 *   fragment: do not use unvalidated user input.
+	 * @param string|array $cond The condition array. See DatabaseBase::select() for details.
+	 * @param string $fname The function name of the caller.
+	 * @param string|array $options The query options. See DatabaseBase::select() for details.
+	 *
+	 * @return bool|array The values from the field, or false on failure
+	 * @since 1.25
+	 */
+	public function selectFieldValues(
+		$table, $var, $cond = '', $fname = __METHOD__, $options = array()
+	) {
+		if ( $var === '*' ) { // sanity
+			throw new DBUnexpectedError( $this, "Cannot use a * field: got '$var'" );
+		}
+
+		if ( !is_array( $options ) ) {
+			$options = array( $options );
+		}
+
+		$res = $this->select( $table, $var, $cond, $fname, $options );
+		if ( $res === false ) {
+			return false;
+		}
+
+		$values = array();
+		foreach ( $res as $row ) {
+			$values[] = $row->$var;
+		}
+
+		return $values;
+	}
+
+	/**
 	 * Returns an optional USE INDEX clause to go after the table, and a
 	 * string to go at the end of the query.
 	 *
@@ -1558,9 +1633,10 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 *     - If the value of such an array element is a scalar (such as a
 	 *       string), it will be treated as data and thus quoted appropriately.
 	 *       If it is null, an IS NULL clause will be added.
-	 *     - If the value is an array, an IN(...) clause will be constructed,
-	 *       such that the field name may match any of the elements in the
-	 *       array. The elements of the array will be quoted.
+	 *     - If the value is an array, an IN (...) clause will be constructed
+	 *       from its non-null elements, and an IS NULL clause will be added
+	 *       if null is present, such that the field may match any of the
+	 *       elements in the array. The non-null elements will be quoted.
 	 *
 	 * Note that expressions are often DBMS-dependent in their syntax.
 	 * DBMS-independent wrappers are provided for constructing several types of
@@ -1779,7 +1855,7 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 
 		if ( $res ) {
 			$row = $this->fetchRow( $res );
-			$rows = ( isset( $row['rowcount'] ) ) ? $row['rowcount'] : 0;
+			$rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
 		}
 
 		return $rows;
@@ -1809,7 +1885,7 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 
 		if ( $res ) {
 			$row = $this->fetchRow( $res );
-			$rows = ( isset( $row['rowcount'] ) ) ? $row['rowcount'] : 0;
+			$rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
 		}
 
 		return $rows;
@@ -2117,16 +2193,36 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 			} elseif ( ( $mode == LIST_SET ) && is_numeric( $field ) ) {
 				$list .= "$value";
 			} elseif ( ( $mode == LIST_AND || $mode == LIST_OR ) && is_array( $value ) ) {
-				if ( count( $value ) == 0 ) {
+				// Remove null from array to be handled separately if found
+				$includeNull = false;
+				foreach ( array_keys( $value, null, true ) as $nullKey ) {
+					$includeNull = true;
+					unset( $value[$nullKey] );
+				}
+				if ( count( $value ) == 0 && !$includeNull ) {
 					throw new MWException( __METHOD__ . ": empty input for field $field" );
-				} elseif ( count( $value ) == 1 ) {
-					// Special-case single values, as IN isn't terribly efficient
-					// Don't necessarily assume the single key is 0; we don't
-					// enforce linear numeric ordering on other arrays here.
-					$value = array_values( $value );
-					$list .= $field . " = " . $this->addQuotes( $value[0] );
+				} elseif ( count( $value ) == 0 ) {
+					// only check if $field is null
+					$list .= "$field IS NULL";
 				} else {
-					$list .= $field . " IN (" . $this->makeList( $value ) . ") ";
+					// IN clause contains at least one valid element
+					if ( $includeNull ) {
+						// Group subconditions to ensure correct precedence
+						$list .= '(';
+					}
+					if ( count( $value ) == 1 ) {
+						// Special-case single values, as IN isn't terribly efficient
+						// Don't necessarily assume the single key is 0; we don't
+						// enforce linear numeric ordering on other arrays here.
+						$value = array_values( $value );
+						$list .= $field . " = " . $this->addQuotes( $value[0] );
+					} else {
+						$list .= $field . " IN (" . $this->makeList( $value ) . ") ";
+					}
+					// if null present in array, append IS NULL
+					if ( $includeNull ) {
+						$list .= " OR $field IS NULL)";
+					}
 				}
 			} elseif ( $value === null ) {
 				if ( $mode == LIST_AND || $mode == LIST_OR ) {
@@ -2322,7 +2418,7 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		# Split database and table into proper variables.
 		# We reverse the explode so that database.table and table both output
 		# the correct table.
-		$dbDetails = explode( '.', $name, 2 );
+		$dbDetails = explode( '.', $name, 3 );
 		if ( count( $dbDetails ) == 3 ) {
 			list( $database, $schema, $table ) = $dbDetails;
 			# We don't want any prefix added in this case
@@ -2552,12 +2648,16 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	}
 
 	/**
-	 * Get the name of an index in a given table
+	 * Get the name of an index in a given table.
 	 *
+	 * @protected Don't use outside of DatabaseBase and childs
 	 * @param string $index
 	 * @return string
 	 */
-	protected function indexName( $index ) {
+	public function indexName( $index ) {
+		// @FIXME: Make this protected once we move away from PHP 5.3
+		// Needs to be public because of usage in closure (in DatabaseBase::replaceVars)
+
 		// Backwards-compatibility hack
 		$renamed = array(
 			'ar_usertext_timestamp' => 'usertext_timestamp',
@@ -2575,10 +2675,13 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	/**
 	 * Adds quotes and backslashes.
 	 *
-	 * @param string $s
+	 * @param string|Blob $s
 	 * @return string
 	 */
 	public function addQuotes( $s ) {
+		if ( $s instanceof Blob ) {
+			$s = $s->fetch();
+		}
 		if ( $s === null ) {
 			return 'NULL';
 		} else {
@@ -3218,41 +3321,40 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 * @return bool
 	 */
 	public function deadlockLoop() {
-		$this->begin( __METHOD__ );
 		$args = func_get_args();
 		$function = array_shift( $args );
-		$oldIgnore = $this->ignoreErrors( true );
 		$tries = self::DEADLOCK_TRIES;
-
 		if ( is_array( $function ) ) {
 			$fname = $function[0];
 		} else {
 			$fname = $function;
 		}
 
-		do {
-			$retVal = call_user_func_array( $function, $args );
-			$error = $this->lastError();
-			$errno = $this->lastErrno();
-			$sql = $this->lastQuery();
+		$this->begin( __METHOD__ );
 
-			if ( $errno ) {
+		$e = null;
+		do {
+			try {
+				$retVal = call_user_func_array( $function, $args );
+				break;
+			} catch ( DBQueryError $e ) {
+				$error = $this->lastError();
+				$errno = $this->lastErrno();
+				$sql = $this->lastQuery();
 				if ( $this->wasDeadlock() ) {
-					# Retry
+					// Retry after a randomized delay
 					usleep( mt_rand( self::DEADLOCK_DELAY_MIN, self::DEADLOCK_DELAY_MAX ) );
 				} else {
-					$this->reportQueryError( $error, $errno, $sql, $fname );
+					// Throw the error back up
+					throw $e;
 				}
 			}
-		} while ( $this->wasDeadlock() && --$tries > 0 );
-
-		$this->ignoreErrors( $oldIgnore );
+		} while ( --$tries > 0 );
 
 		if ( $tries <= 0 ) {
+			// Too many deadlocks; give up
 			$this->rollback( __METHOD__ );
-			$this->reportQueryError( $error, $errno, $sql, $fname );
-
-			return false;
+			throw $e;
 		} else {
 			$this->commit( __METHOD__ );
 
@@ -3486,7 +3588,12 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 				$msg = "$fname: Transaction already in progress (from {$this->mTrxFname}), " .
 					" performing implicit commit!";
 				wfWarn( $msg );
-				wfLogDBError( $msg );
+				wfLogDBError( $msg,
+					$this->getLogContext( array(
+						'method' => __METHOD__,
+						'fname' => $fname,
+					) )
+				);
 			} else {
 				// if the transaction was automatic and has done write operations,
 				// log it if $wgDebugDBTransactions is enabled.
@@ -3500,7 +3607,8 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 			$this->runOnTransactionPreCommitCallbacks();
 			$this->doCommit( $fname );
 			if ( $this->mTrxDoneWrites ) {
-				Profiler::instance()->transactionWritingOut(
+				$this->mDoneWrites = microtime( true );
+				$this->getTransactionProfiler()->transactionWritingOut(
 					$this->mServer, $this->mDBname, $this->mTrxShortId );
 			}
 			$this->runOnTransactionIdleCallbacks();
@@ -3512,6 +3620,7 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		}
 
 		$this->doBegin( $fname );
+		$this->mTrxTimestamp = microtime( true );
 		$this->mTrxFname = $fname;
 		$this->mTrxDoneWrites = false;
 		$this->mTrxAutomatic = false;
@@ -3579,7 +3688,8 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		$this->runOnTransactionPreCommitCallbacks();
 		$this->doCommit( $fname );
 		if ( $this->mTrxDoneWrites ) {
-			Profiler::instance()->transactionWritingOut(
+			$this->mDoneWrites = microtime( true );
+			$this->getTransactionProfiler()->transactionWritingOut(
 				$this->mServer, $this->mDBname, $this->mTrxShortId );
 		}
 		$this->runOnTransactionIdleCallbacks();
@@ -3609,6 +3719,7 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 *   calling rollback when no transaction is in progress. This will silently
 	 *   break any ongoing explicit transaction. Only set the flush flag if you
 	 *   are sure that it is safe to ignore these warnings in your context.
+	 * @throws DBUnexpectedError
 	 * @since 1.23 Added $flush parameter
 	 */
 	final public function rollback( $fname = __METHOD__, $flush = '' ) {
@@ -3637,7 +3748,7 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 		$this->mTrxPreCommitCallbacks = array(); // cancel
 		$this->mTrxAtomicLevels = new SplStack;
 		if ( $this->mTrxDoneWrites ) {
-			Profiler::instance()->transactionWritingOut(
+			$this->getTransactionProfiler()->transactionWritingOut(
 				$this->mServer, $this->mDBname, $this->mTrxShortId );
 		}
 	}
@@ -3835,10 +3946,13 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 * in result objects. Pass the object through this function to return the
 	 * original string.
 	 *
-	 * @param string $b
+	 * @param string|Blob $b
 	 * @return string
 	 */
 	public function decodeBlob( $b ) {
+		if ( $b instanceof Blob ) {
+			$b = $b->fetch();
+		}
 		return $b;
 	}
 
@@ -3888,7 +4002,7 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 
 		try {
 			$error = $this->sourceStream( $fp, $lineCallback, $resultCallback, $fname, $inputCallback );
-		} catch ( MWException $e ) {
+		} catch ( Exception $e ) {
 			fclose( $fp );
 			throw $e;
 		}
@@ -4019,47 +4133,49 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 *
 	 * - '{$var}' should be used for text and is passed through the database's
 	 *   addQuotes method.
-	 * - `{$var}` should be used for identifiers (eg: table and database names),
-	 *   it is passed through the database's addIdentifierQuotes method which
+	 * - `{$var}` should be used for identifiers (e.g. table and database names).
+	 *   It is passed through the database's addIdentifierQuotes method which
 	 *   can be overridden if the database uses something other than backticks.
-	 * - / *$var* / is just encoded, besides traditional table prefix and
-	 *   table options its use should be avoided.
+	 * - / *_* / or / *$wgDBprefix* / passes the name that follows through the
+	 *   database's tableName method.
+	 * - / *i* / passes the name that follows through the database's indexName method.
+	 * - In all other cases, / *$var* / is left unencoded. Except for table options,
+	 *   its use should be avoided. In 1.24 and older, string encoding was applied.
 	 *
 	 * @param string $ins SQL statement to replace variables in
 	 * @return string The new SQL statement with variables replaced
 	 */
-	protected function replaceSchemaVars( $ins ) {
-		$vars = $this->getSchemaVars();
-		foreach ( $vars as $var => $value ) {
-			// replace '{$var}'
-			$ins = str_replace( '\'{$' . $var . '}\'', $this->addQuotes( $value ), $ins );
-			// replace `{$var}`
-			$ins = str_replace( '`{$' . $var . '}`', $this->addIdentifierQuotes( $value ), $ins );
-			// replace /*$var*/
-			$ins = str_replace( '/*$' . $var . '*/', $this->strencode( $value ), $ins );
-		}
-
-		return $ins;
-	}
-
-	/**
-	 * Replace variables in sourced SQL
-	 *
-	 * @param string $ins
-	 * @return string
-	 */
 	protected function replaceVars( $ins ) {
-		$ins = $this->replaceSchemaVars( $ins );
-
-		// Table prefixes
-		$ins = preg_replace_callback( '!/\*(?:\$wgDBprefix|_)\*/([a-zA-Z_0-9]*)!',
-			array( $this, 'tableNameCallback' ), $ins );
-
-		// Index names
-		$ins = preg_replace_callback( '!/\*i\*/([a-zA-Z_0-9]*)!',
-			array( $this, 'indexNameCallback' ), $ins );
-
-		return $ins;
+		$that = $this;
+		$vars = $this->getSchemaVars();
+		return preg_replace_callback(
+			'!
+				/\* (\$wgDBprefix|[_i]) \*/ (\w*) | # 1-2. tableName, indexName
+				\'\{\$ (\w+) }\'                  | # 3. addQuotes
+				`\{\$ (\w+) }`                    | # 4. addIdentifierQuotes
+				/\*\$ (\w+) \*/                     # 5. leave unencoded
+			!x',
+			function ( $m ) use ( $that, $vars ) {
+				// Note: Because of <https://bugs.php.net/bug.php?id=51881>,
+				// check for both nonexistent keys *and* the empty string.
+				if ( isset( $m[1] ) && $m[1] !== '' ) {
+					if ( $m[1] === 'i' ) {
+						return $that->indexName( $m[2] );
+					} else {
+						return $that->tableName( $m[2] );
+					}
+				} elseif ( isset( $m[3] ) && $m[3] !== '' && array_key_exists( $m[3], $vars ) ) {
+					return $that->addQuotes( $vars[$m[3]] );
+				} elseif ( isset( $m[4] ) && $m[4] !== '' && array_key_exists( $m[4], $vars ) ) {
+					return $that->addIdentifierQuotes( $vars[$m[4]] );
+				} elseif ( isset( $m[5] ) && $m[5] !== '' && array_key_exists( $m[5], $vars ) ) {
+					return $vars[$m[5]];
+				} else {
+					return $m[0];
+				}
+			},
+			$ins
+		);
 	}
 
 	/**
@@ -4089,26 +4205,6 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	}
 
 	/**
-	 * Table name callback
-	 *
-	 * @param array $matches
-	 * @return string
-	 */
-	protected function tableNameCallback( $matches ) {
-		return $this->tableName( $matches[1] );
-	}
-
-	/**
-	 * Index name callback
-	 *
-	 * @param array $matches
-	 * @return string
-	 */
-	protected function indexNameCallback( $matches ) {
-		return $this->indexName( $matches[1] );
-	}
-
-	/**
 	 * Check to see if a named lock is available. This is non-blocking.
 	 *
 	 * @param string $lockName Name of lock to poll
diff --git a/includes/db/DatabaseError.php b/includes/db/DatabaseError.php
index 2dfec41d..86950a89 100644
--- a/includes/db/DatabaseError.php
+++ b/includes/db/DatabaseError.php
@@ -168,12 +168,12 @@ class DBConnectionError extends DBExpectedError {
 		if ( $wgShowHostnames || $wgShowSQLErrors ) {
 			$info = str_replace(
 				'$1', Html::element( 'span', array( 'dir' => 'ltr' ), $this->error ),
-				htmlspecialchars( $this->msg( 'dberr-info', '(Cannot contact the database server: $1)' ) )
+				htmlspecialchars( $this->msg( 'dberr-info', '(Cannot access the database: $1)' ) )
 			);
 		} else {
 			$info = htmlspecialchars( $this->msg(
 				'dberr-info-hidden',
-				'(Cannot contact the database server)'
+				'(Cannot access the database)'
 			) );
 		}
 
@@ -229,7 +229,7 @@ class DBConnectionError extends DBExpectedError {
 
 					return;
 				}
-			} catch ( MWException $e ) {
+			} catch ( Exception $e ) {
 				// Do nothing, just use the default page
 			}
 		}
diff --git a/includes/db/DatabaseMssql.php b/includes/db/DatabaseMssql.php
index af3cc72d..2b8f395f 100644
--- a/includes/db/DatabaseMssql.php
+++ b/includes/db/DatabaseMssql.php
@@ -380,6 +380,9 @@ class DatabaseMssql extends DatabaseBase {
 	 *   (optional) (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 	 * @return mixed Database result resource (feed to Database::fetchObject
 	 *   or whatever), or false on failure
+	 * @throws DBQueryError
+	 * @throws DBUnexpectedError
+	 * @throws Exception
 	 */
 	public function select( $table, $vars, $conds = '', $fname = __METHOD__,
 		$options = array(), $join_conds = array()
@@ -515,7 +518,7 @@ class DatabaseMssql extends DatabaseBase {
 			$row = $this->fetchRow( $res );
 
 			if ( isset( $row['EstimateRows'] ) ) {
-				$rows = $row['EstimateRows'];
+				$rows = (int)$row['EstimateRows'];
 			}
 		}
 
@@ -574,8 +577,8 @@ class DatabaseMssql extends DatabaseBase {
 	 * @param array $arrToInsert
 	 * @param string $fname
 	 * @param array $options
-	 * @throws DBQueryError
 	 * @return bool
+	 * @throws Exception
 	 */
 	public function insert( $table, $arrToInsert, $fname = __METHOD__, $options = array() ) {
 		# No rows to insert, easy just return now
@@ -692,7 +695,7 @@ class DatabaseMssql extends DatabaseBase {
 			if ( !is_null( $identity ) ) {
 				// then we want to get the identity column value we were assigned and save it off
 				$row = $ret->fetchObject();
-				if( is_object( $row ) ){
+				if ( is_object( $row ) ) {
 					$this->mInsertId = $row->$identity;
 				}
 			}
@@ -713,8 +716,8 @@ class DatabaseMssql extends DatabaseBase {
 	 * @param string $fname
 	 * @param array $insertOptions
 	 * @param array $selectOptions
-	 * @throws DBQueryError
 	 * @return null|ResultWrapper
+	 * @throws Exception
 	 */
 	public function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 		$insertOptions = array(), $selectOptions = array()
@@ -761,6 +764,9 @@ class DatabaseMssql extends DatabaseBase {
 	 *                   - IGNORE: Ignore unique key conflicts
 	 *                   - LOW_PRIORITY: MySQL-specific, see MySQL manual.
 	 * @return bool
+	 * @throws DBUnexpectedError
+	 * @throws Exception
+	 * @throws MWException
 	 */
 	function update( $table, $values, $conds, $fname = __METHOD__, $options = array() ) {
 		$table = $this->tableName( $table );
@@ -806,64 +812,27 @@ class DatabaseMssql extends DatabaseBase {
 				'DatabaseBase::makeList called with incorrect parameters' );
 		}
 
-		$first = true;
-		$list = '';
+		if ( $mode != LIST_NAMES ) {
+			// In MS SQL, values need to be specially encoded when they are
+			// inserted into binary fields. Perform this necessary encoding
+			// for the specified set of columns.
+			foreach ( array_keys( $a ) as $field ) {
+				if ( !isset( $binaryColumns[$field] ) ) {
+					continue;
+				}
 
-		foreach ( $a as $field => $value ) {
-			if ( $mode != LIST_NAMES && isset( $binaryColumns[$field] ) ) {
-				if ( is_array( $value ) ) {
-					foreach ( $value as &$v ) {
+				if ( is_array( $a[$field] ) ) {
+					foreach ( $a[$field] as &$v ) {
 						$v = new MssqlBlob( $v );
 					}
+					unset( $v );
 				} else {
-					$value = new MssqlBlob( $value );
-				}
-			}
-
-			if ( !$first ) {
-				if ( $mode == LIST_AND ) {
-					$list .= ' AND ';
-				} elseif ( $mode == LIST_OR ) {
-					$list .= ' OR ';
-				} else {
-					$list .= ',';
+					$a[$field] = new MssqlBlob( $a[$field] );
 				}
-			} else {
-				$first = false;
-			}
-
-			if ( ( $mode == LIST_AND || $mode == LIST_OR ) && is_numeric( $field ) ) {
-				$list .= "($value)";
-			} elseif ( ( $mode == LIST_SET ) && is_numeric( $field ) ) {
-				$list .= "$value";
-			} elseif ( ( $mode == LIST_AND || $mode == LIST_OR ) && is_array( $value ) ) {
-				if ( count( $value ) == 0 ) {
-					throw new MWException( __METHOD__ . ": empty input for field $field" );
-				} elseif ( count( $value ) == 1 ) {
-					// Special-case single values, as IN isn't terribly efficient
-					// Don't necessarily assume the single key is 0; we don't
-					// enforce linear numeric ordering on other arrays here.
-					$value = array_values( $value );
-					$list .= $field . " = " . $this->addQuotes( $value[0] );
-				} else {
-					$list .= $field . " IN (" . $this->makeList( $value ) . ") ";
-				}
-			} elseif ( $value === null ) {
-				if ( $mode == LIST_AND || $mode == LIST_OR ) {
-					$list .= "$field IS ";
-				} elseif ( $mode == LIST_SET ) {
-					$list .= "$field = ";
-				}
-				$list .= 'NULL';
-			} else {
-				if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
-					$list .= "$field = ";
-				}
-				$list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
 			}
 		}
 
-		return $list;
+		return parent::makeList( $a, $mode );
 	}
 
 	/**
@@ -893,6 +862,7 @@ class DatabaseMssql extends DatabaseBase {
 	 * @param int $limit The SQL limit
 	 * @param bool|int $offset The SQL offset (default false)
 	 * @return array|string
+	 * @throws DBUnexpectedError
 	 */
 	public function limitResult( $sql, $limit, $offset = false ) {
 		if ( $offset === false || $offset == 0 ) {
@@ -953,12 +923,8 @@ class DatabaseMssql extends DatabaseBase {
 		// Matches: LIMIT {[offset,] row_count | row_count OFFSET offset}
 		$pattern = '/\bLIMIT\s+((([0-9]+)\s*,\s*)?([0-9]+)(\s+OFFSET\s+([0-9]+))?)/i';
 		if ( preg_match( $pattern, $sql, $matches ) ) {
-			// row_count = $matches[4]
 			$row_count = $matches[4];
-			// offset = $matches[3] OR $matches[6]
-			$offset = $matches[3] or
-			$offset = $matches[6] or
-			$offset = false;
+			$offset = $matches[3] ?: $matches[6] ?: false;
 
 			// strip the matching LIMIT clause out
 			$sql = str_replace( $matches[0], '', $sql );
@@ -1128,7 +1094,7 @@ class DatabaseMssql extends DatabaseBase {
 	}
 
 	/**
-	 * @param string $s
+	 * @param string|Blob $s
 	 * @return string
 	 */
 	public function addQuotes( $s ) {
diff --git a/includes/db/DatabaseMysql.php b/includes/db/DatabaseMysql.php
index dc4a67df..823d9b67 100644
--- a/includes/db/DatabaseMysql.php
+++ b/includes/db/DatabaseMysql.php
@@ -142,13 +142,6 @@ class DatabaseMysql extends DatabaseMysqlBase {
 		return mysql_select_db( $db, $this->mConn );
 	}
 
-	/**
-	 * @return string
-	 */
-	function getServerVersion() {
-		return mysql_get_server_info( $this->mConn );
-	}
-
 	protected function mysqlFreeResult( $res ) {
 		return mysql_free_result( $res );
 	}
diff --git a/includes/db/DatabaseMysqlBase.php b/includes/db/DatabaseMysqlBase.php
index ba0f39ff..aac95a8c 100644
--- a/includes/db/DatabaseMysqlBase.php
+++ b/includes/db/DatabaseMysqlBase.php
@@ -38,6 +38,9 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 
 	protected $mFakeMaster = false;
 
+	/** @var string|null */
+	private $serverVersion = null;
+
 	/**
 	 * @return string
 	 */
@@ -55,7 +58,6 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 	 */
 	function open( $server, $user, $password, $dbName ) {
 		global $wgAllDBsAreLocalhost, $wgSQLMode;
-		wfProfileIn( __METHOD__ );
 
 		# Debugging hack -- fake cluster
 		if ( $wgAllDBsAreLocalhost ) {
@@ -69,8 +71,6 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 		$this->mPassword = $password;
 		$this->mDBname = $dbName;
 
-		wfProfileIn( "dbconnect-$server" );
-
 		# The kernel's default SYN retransmission period is far too slow for us,
 		# so we use a short timeout plus a manual retry. Retrying means that a small
 		# but finite rate of SYN packet loss won't cause user-visible errors.
@@ -79,27 +79,27 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 		try {
 			$this->mConn = $this->mysqlConnect( $realServer );
 		} catch ( Exception $ex ) {
-			wfProfileOut( "dbconnect-$server" );
-			wfProfileOut( __METHOD__ );
 			$this->restoreErrorHandler();
 			throw $ex;
 		}
 		$error = $this->restoreErrorHandler();
 
-		wfProfileOut( "dbconnect-$server" );
-
 		# Always log connection errors
 		if ( !$this->mConn ) {
 			if ( !$error ) {
 				$error = $this->lastError();
 			}
-			wfLogDBError( "Error connecting to {$this->mServer}: $error" );
+			wfLogDBError(
+				"Error connecting to {db_server}: {error}",
+				$this->getLogContext( array(
+					'method' => __METHOD__,
+					'error' => $error,
+				) )
+			);
 			wfDebug( "DB connection error\n" .
 				"Server: $server, User: $user, Password: " .
 				substr( $password, 0, 3 ) . "..., error: " . $error . "\n" );
 
-			wfProfileOut( __METHOD__ );
-
 			$this->reportConnectionError( $error );
 		}
 
@@ -108,12 +108,15 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 			$success = $this->selectDB( $dbName );
 			wfRestoreWarnings();
 			if ( !$success ) {
-				wfLogDBError( "Error selecting database $dbName on server {$this->mServer}" );
+				wfLogDBError(
+					"Error selecting database {db_name} on server {db_server}",
+					$this->getLogContext( array(
+						'method' => __METHOD__,
+					) )
+				);
 				wfDebug( "Error selecting database $dbName on server {$this->mServer} " .
 					"from client host " . wfHostname() . "\n" );
 
-				wfProfileOut( __METHOD__ );
-
 				$this->reportConnectionError( "Error selecting database $dbName" );
 			}
 		}
@@ -123,20 +126,29 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 			$this->reportConnectionError( "Error setting character set" );
 		}
 
+		// Abstract over any insane MySQL defaults
+		$set = array( 'group_concat_max_len = 262144' );
 		// Set SQL mode, default is turning them all off, can be overridden or skipped with null
 		if ( is_string( $wgSQLMode ) ) {
-			$mode = $this->addQuotes( $wgSQLMode );
+			$set[] = 'sql_mode = ' . $this->addQuotes( $wgSQLMode );
+		}
+
+		if ( $set ) {
 			// Use doQuery() to avoid opening implicit transactions (DBO_TRX)
-			$success = $this->doQuery( "SET sql_mode = $mode", __METHOD__ );
+			$success = $this->doQuery( 'SET ' . implode( ', ', $set ), __METHOD__ );
 			if ( !$success ) {
-				wfLogDBError( "Error setting sql_mode to $mode on server {$this->mServer}" );
-				wfProfileOut( __METHOD__ );
-				$this->reportConnectionError( "Error setting sql_mode to $mode" );
+				wfLogDBError(
+					'Error setting MySQL variables on server {db_server} (check $wgSQLMode)',
+					$this->getLogContext( array(
+						'method' => __METHOD__,
+					) )
+				);
+				$this->reportConnectionError(
+					'Error setting MySQL variables on server {db_server} (check $wgSQLMode)' );
 			}
 		}
 
 		$this->mOpened = true;
-		wfProfileOut( __METHOD__ );
 
 		return true;
 	}
@@ -456,7 +468,7 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 			$rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 		}
 
-		return $rows;
+		return (int)$rows;
 	}
 
 	/**
@@ -652,7 +664,6 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 			return '0'; // http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html
 		}
 
-		wfProfileIn( __METHOD__ );
 		# Commit any open transactions
 		$this->commit( __METHOD__, 'flush' );
 
@@ -661,18 +672,15 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 
 			if ( $wait > $timeout * 1e6 ) {
 				wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
-				wfProfileOut( __METHOD__ );
 
 				return -1;
 			} elseif ( $wait > 0 ) {
 				wfDebug( "Fake slave waiting $wait us\n" );
 				usleep( $wait );
-				wfProfileOut( __METHOD__ );
 
 				return 1;
 			} else {
 				wfDebug( "Fake slave up to date ($wait us)\n" );
-				wfProfileOut( __METHOD__ );
 
 				return 0;
 			}
@@ -692,8 +700,6 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 			}
 		}
 
-		wfProfileOut( __METHOD__ );
-
 		return $status;
 	}
 
@@ -763,9 +769,9 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 	 * @return string
 	 */
 	public function getSoftwareLink() {
-		// MariaDB includes its name in its version string (sent when the connection is opened),
-		// and this is how MariaDB's version of the mysql command-line client identifies MariaDB
-		// servers (see the mariadb_connection() function in libmysql/libmysql.c).
+		// MariaDB includes its name in its version string; this is how MariaDB's version of
+		// the mysql command-line client identifies MariaDB servers (see mariadb_connection()
+		// in libmysql/libmysql.c).
 		$version = $this->getServerVersion();
 		if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
 			return '[{{int:version-db-mariadb-url}} MariaDB]';
@@ -778,6 +784,19 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
 	}
 
 	/**
+	 * @return string
+	 */
+	public function getServerVersion() {
+		// Not using mysql_get_server_info() or similar for consistency: in the handshake,
+		// MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
+		// it off (see RPL_VERSION_HACK in include/mysql_com.h).
+		if ( $this->serverVersion === null ) {
+			$this->serverVersion = $this->selectField( '', 'VERSION()', '', __METHOD__ );
+		}
+		return $this->serverVersion;
+	}
+
+	/**
 	 * @param array $options
 	 */
 	public function setSessionOptions( array $options ) {
@@ -1169,7 +1188,8 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
  */
 class MySQLField implements Field {
 	private $name, $tablename, $default, $max_length, $nullable,
-		$is_pk, $is_unique, $is_multiple, $is_key, $type, $binary;
+		$is_pk, $is_unique, $is_multiple, $is_key, $type, $binary,
+		$is_numeric, $is_blob, $is_unsigned, $is_zerofill;
 
 	function __construct( $info ) {
 		$this->name = $info->name;
@@ -1183,6 +1203,10 @@ class MySQLField implements Field {
 		$this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
 		$this->type = $info->type;
 		$this->binary = isset( $info->binary ) ? $info->binary : false;
+		$this->is_numeric = isset( $info->numeric ) ? $info->numeric : false;
+		$this->is_blob = isset( $info->blob ) ? $info->blob : false;
+		$this->is_unsigned = isset( $info->unsigned ) ? $info->unsigned : false;
+		$this->is_zerofill = isset( $info->zerofill ) ? $info->zerofill : false;
 	}
 
 	/**
@@ -1231,21 +1255,54 @@ class MySQLField implements Field {
 		return $this->is_multiple;
 	}
 
+	/**
+	 * @return bool
+	 */
 	function isBinary() {
 		return $this->binary;
 	}
+
+	/**
+	 * @return bool
+	 */
+	function isNumeric() {
+		return $this->is_numeric;
+	}
+
+	/**
+	 * @return bool
+	 */
+	function isBlob() {
+		return $this->is_blob;
+	}
+
+	/**
+	 * @return bool
+	 */
+	function isUnsigned() {
+		return $this->is_unsigned;
+	}
+
+	/**
+	 * @return bool
+	 */
+	function isZerofill() {
+		return $this->is_zerofill;
+	}
 }
 
 class MySQLMasterPos implements DBMasterPos {
 	/** @var string */
 	public $file;
-
-	/** @var int Timestamp */
+	/** @var int Position */
 	public $pos;
+	/** @var float UNIX timestamp */
+	public $asOfTime = 0.0;
 
 	function __construct( $file, $pos ) {
 		$this->file = $file;
 		$this->pos = $pos;
+		$this->asOfTime = microtime( true );
 	}
 
 	function __toString() {
@@ -1271,4 +1328,8 @@ class MySQLMasterPos implements DBMasterPos {
 
 		return ( $thisPos && $thatPos && $thisPos >= $thatPos );
 	}
+
+	function asOfTime() {
+		return $this->asOfTime;
+	}
 }
diff --git a/includes/db/DatabaseMysqli.php b/includes/db/DatabaseMysqli.php
index a03c9aaf..ad12e196 100644
--- a/includes/db/DatabaseMysqli.php
+++ b/includes/db/DatabaseMysqli.php
@@ -166,13 +166,6 @@ class DatabaseMysqli extends DatabaseMysqlBase {
 	}
 
 	/**
-	 * @return string
-	 */
-	function getServerVersion() {
-		return $this->mConn->server_info;
-	}
-
-	/**
 	 * @param mysqli $res
 	 * @return bool
 	 */
@@ -231,11 +224,18 @@ class DatabaseMysqli extends DatabaseMysqlBase {
 	 */
 	protected function mysqlFetchField( $res, $n ) {
 		$field = $res->fetch_field_direct( $n );
+
+		// Add missing properties to result (using flags property)
+		// which will be part of function mysql-fetch-field for backward compatibility
 		$field->not_null = $field->flags & MYSQLI_NOT_NULL_FLAG;
 		$field->primary_key = $field->flags & MYSQLI_PRI_KEY_FLAG;
 		$field->unique_key = $field->flags & MYSQLI_UNIQUE_KEY_FLAG;
 		$field->multiple_key = $field->flags & MYSQLI_MULTIPLE_KEY_FLAG;
 		$field->binary = $field->flags & MYSQLI_BINARY_FLAG;
+		$field->numeric = $field->flags & MYSQLI_NUM_FLAG;
+		$field->blob = $field->flags & MYSQLI_BLOB_FLAG;
+		$field->unsigned = $field->flags & MYSQLI_UNSIGNED_FLAG;
+		$field->zerofill = $field->flags & MYSQLI_ZEROFILL_FLAG;
 
 		return $field;
 	}
diff --git a/includes/db/DatabaseOracle.php b/includes/db/DatabaseOracle.php
index f031f780..9b00fbd1 100644
--- a/includes/db/DatabaseOracle.php
+++ b/includes/db/DatabaseOracle.php
@@ -207,29 +207,15 @@ class DatabaseOracle extends DatabaseBase {
 	/** @var array */
 	private $mFieldInfoCache = array();
 
-	function __construct( $p = null ) {
+	function __construct( array $p ) {
 		global $wgDBprefix;
 
-		if ( !is_array( $p ) ) { // legacy calling pattern
-			wfDeprecated( __METHOD__ . " method called without parameter array.", "1.22" );
-			$args = func_get_args();
-			$p = array(
-				'host' => isset( $args[0] ) ? $args[0] : false,
-				'user' => isset( $args[1] ) ? $args[1] : false,
-				'password' => isset( $args[2] ) ? $args[2] : false,
-				'dbname' => isset( $args[3] ) ? $args[3] : false,
-				'flags' => isset( $args[4] ) ? $args[4] : 0,
-				'tablePrefix' => isset( $args[5] ) ? $args[5] : 'get from global',
-				'schema' => 'get from global',
-				'foreign' => isset( $args[6] ) ? $args[6] : false
-			);
-		}
 		if ( $p['tablePrefix'] == 'get from global' ) {
 			$p['tablePrefix'] = $wgDBprefix;
 		}
 		$p['tablePrefix'] = strtoupper( $p['tablePrefix'] );
 		parent::__construct( $p );
-		wfRunHooks( 'DatabaseOraclePostInit', array( $this ) );
+		Hooks::run( 'DatabaseOraclePostInit', array( $this ) );
 	}
 
 	function __destruct() {
diff --git a/includes/db/DatabasePostgres.php b/includes/db/DatabasePostgres.php
index ce14d7a9..9287f7a6 100644
--- a/includes/db/DatabasePostgres.php
+++ b/includes/db/DatabasePostgres.php
@@ -530,10 +530,12 @@ class DatabasePostgres extends DatabaseBase {
 				return;
 			}
 		}
-		/* Transaction stays in the ERROR state until rolledback */
+		/* Transaction stays in the ERROR state until rolled back */
 		if ( $this->mTrxLevel ) {
+			$ignore = $this->ignoreErrors( true );
 			$this->rollback( __METHOD__ );
-		};
+			$this->ignoreErrors( $ignore );
+		}
 		parent::reportQueryError( $error, $errno, $sql, $fname, false );
 	}
 
@@ -712,7 +714,7 @@ class DatabasePostgres extends DatabaseBase {
 			$row = $this->fetchRow( $res );
 			$count = array();
 			if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
-				$rows = $count[1];
+				$rows = (int)$count[1];
 			}
 		}
 
@@ -1495,12 +1497,14 @@ SQL;
 	 * @return Blob
 	 */
 	function encodeBlob( $b ) {
-		return new Blob( pg_escape_bytea( $this->mConn, $b ) );
+		return new PostgresBlob( pg_escape_bytea( $b ) );
 	}
 
 	function decodeBlob( $b ) {
-		if ( $b instanceof Blob ) {
+		if ( $b instanceof PostgresBlob ) {
 			$b = $b->fetch();
+		} elseif ( $b instanceof Blob ) {
+			return $b->fetch();
 		}
 
 		return pg_unescape_bytea( $b );
@@ -1520,7 +1524,12 @@ SQL;
 		} elseif ( is_bool( $s ) ) {
 			return intval( $s );
 		} elseif ( $s instanceof Blob ) {
-			return "'" . $s->fetch( $s ) . "'";
+			if ( $s instanceof PostgresBlob ) {
+				$s = $s->fetch();
+			} else {
+				$s = pg_escape_bytea( $this->mConn, $s->fetch() );
+			}
+			return "'$s'";
 		}
 
 		return "'" . pg_escape_string( $this->mConn, $s ) . "'";
@@ -1692,3 +1701,5 @@ SQL;
 		return wfBaseConvert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
 	}
 } // end DatabasePostgres class
+
+class PostgresBlob extends Blob {}
diff --git a/includes/db/DatabaseSqlite.php b/includes/db/DatabaseSqlite.php
index dd2e813e..ed86bab1 100644
--- a/includes/db/DatabaseSqlite.php
+++ b/includes/db/DatabaseSqlite.php
@@ -29,8 +29,14 @@ class DatabaseSqlite extends DatabaseBase {
 	/** @var bool Whether full text is enabled */
 	private static $fulltextEnabled = null;
 
+	/** @var string Directory */
+	protected $dbDir;
+
 	/** @var string File name for SQLite database file */
-	public $mDatabaseFile;
+	protected $dbPath;
+
+	/** @var string Transaction mode */
+	protected $trxMode;
 
 	/** @var int The number of rows affected as an integer */
 	protected $mAffectedRows;
@@ -44,35 +50,63 @@ class DatabaseSqlite extends DatabaseBase {
 	/** @var FSLockManager (hopefully on the same server as the DB) */
 	protected $lockMgr;
 
-	function __construct( $p = null ) {
+	/**
+	 * Additional params include:
+	 *   - dbDirectory : directory containing the DB and the lock file directory
+	 *                   [defaults to $wgSQLiteDataDir]
+	 *   - dbFilePath  : use this to force the path of the DB file
+	 *   - trxMode     : one of (deferred, immediate, exclusive)
+	 * @param array $p
+	 */
+	function __construct( array $p ) {
 		global $wgSharedDB, $wgSQLiteDataDir;
 
-		if ( !is_array( $p ) ) { // legacy calling pattern
-			wfDeprecated( __METHOD__ . " method called without parameter array.", "1.22" );
-			$args = func_get_args();
-			$p = array(
-				'host' => isset( $args[0] ) ? $args[0] : false,
-				'user' => isset( $args[1] ) ? $args[1] : false,
-				'password' => isset( $args[2] ) ? $args[2] : false,
-				'dbname' => isset( $args[3] ) ? $args[3] : false,
-				'flags' => isset( $args[4] ) ? $args[4] : 0,
-				'tablePrefix' => isset( $args[5] ) ? $args[5] : 'get from global',
-				'schema' => 'get from global',
-				'foreign' => isset( $args[6] ) ? $args[6] : false
-			);
-		}
-		$this->mDBname = $p['dbname'];
-		parent::__construct( $p );
-		// parent doesn't open when $user is false, but we can work with $dbName
-		if ( $p['dbname'] && !$this->isOpen() ) {
-			if ( $this->open( $p['host'], $p['user'], $p['password'], $p['dbname'] ) ) {
-				if ( $wgSharedDB ) {
-					$this->attachDatabase( $wgSharedDB );
+		$this->dbDir = isset( $p['dbDirectory'] ) ? $p['dbDirectory'] : $wgSQLiteDataDir;
+
+		if ( isset( $p['dbFilePath'] ) ) {
+			$this->mFlags = isset( $p['flags'] ) ? $p['flags'] : 0;
+			// Standalone .sqlite file mode
+			$this->openFile( $p['dbFilePath'] );
+			// @FIXME: clean up base constructor so this can call super instead
+			$this->mTrxAtomicLevels = new SplStack;
+		} else {
+			$this->mDBname = $p['dbname'];
+			// Stock wiki mode using standard file names per DB
+			parent::__construct( $p );
+			// parent doesn't open when $user is false, but we can work with $dbName
+			if ( $p['dbname'] && !$this->isOpen() ) {
+				if ( $this->open( $p['host'], $p['user'], $p['password'], $p['dbname'] ) ) {
+					if ( $wgSharedDB ) {
+						$this->attachDatabase( $wgSharedDB );
+					}
 				}
 			}
 		}
 
-		$this->lockMgr = new FSLockManager( array( 'lockDirectory' => "$wgSQLiteDataDir/locks" ) );
+		$this->trxMode = isset( $p['trxMode'] ) ? strtoupper( $p['trxMode'] ) : null;
+		if ( $this->trxMode &&
+			!in_array( $this->trxMode, array( 'DEFERRED', 'IMMEDIATE', 'EXCLUSIVE' ) )
+		) {
+			$this->trxMode = null;
+			wfWarn( "Invalid SQLite transaction mode provided." );
+		}
+
+		$this->lockMgr = new FSLockManager( array( 'lockDirectory' => "{$this->dbDir}/locks" ) );
+	}
+
+	/**
+	 * @param string $filename
+	 * @param array $p Options map; supports:
+	 *   - flags       : (same as __construct counterpart)
+	 *   - trxMode     : (same as __construct counterpart)
+	 *   - dbDirectory : (same as __construct counterpart)
+	 * @return DatabaseSqlite
+	 * @since 1.25
+	 */
+	public static function newStandaloneInstance( $filename, array $p = array() ) {
+		$p['dbFilePath'] = $filename;
+
+		return new self( $p );
 	}
 
 	/**
@@ -103,10 +137,8 @@ class DatabaseSqlite extends DatabaseBase {
 	 * @return PDO
 	 */
 	function open( $server, $user, $pass, $dbName ) {
-		global $wgSQLiteDataDir;
-
 		$this->close();
-		$fileName = self::generateFileName( $wgSQLiteDataDir, $dbName );
+		$fileName = self::generateFileName( $this->dbDir, $dbName );
 		if ( !is_readable( $fileName ) ) {
 			$this->mConn = false;
 			throw new DBConnectionError( $this, "SQLite database not accessible" );
@@ -123,10 +155,10 @@ class DatabaseSqlite extends DatabaseBase {
 	 * @throws DBConnectionError
 	 * @return PDO|bool SQL connection or false if failed
 	 */
-	function openFile( $fileName ) {
+	protected function openFile( $fileName ) {
 		$err = false;
 
-		$this->mDatabaseFile = $fileName;
+		$this->dbPath = $fileName;
 		try {
 			if ( $this->mFlags & DBO_PERSISTENT ) {
 				$this->mConn = new PDO( "sqlite:$fileName", '', '',
@@ -144,8 +176,8 @@ class DatabaseSqlite extends DatabaseBase {
 		}
 
 		$this->mOpened = !!$this->mConn;
-		# set error codes only, don't raise exceptions
 		if ( $this->mOpened ) {
+			# Set error codes only, don't raise exceptions
 			$this->mConn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT );
 			# Enforce LIKE to be case sensitive, just like MySQL
 			$this->query( 'PRAGMA case_sensitive_like = 1' );
@@ -157,6 +189,14 @@ class DatabaseSqlite extends DatabaseBase {
 	}
 
 	/**
+	 * @return string SQLite DB file path
+	 * @since 1.25
+	 */
+	public function getDbFilePath() {
+		return $this->dbPath;
+	}
+
+	/**
 	 * Does not actually close the connection, just destroys the reference for GC to do its work
 	 * @return bool
 	 */
@@ -206,8 +246,7 @@ class DatabaseSqlite extends DatabaseBase {
 		$cachedResult = false;
 		$table = 'dummy_search_test';
 
-		$db = new DatabaseSqliteStandalone( ':memory:' );
-
+		$db = self::newStandaloneInstance( ':memory:' );
 		if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 			$cachedResult = 'FTS3';
 		}
@@ -223,14 +262,13 @@ class DatabaseSqlite extends DatabaseBase {
 	 * @param string $name Database name to be used in queries like
 	 *   SELECT foo FROM dbname.table
 	 * @param bool|string $file Database file name. If omitted, will be generated
-	 *   using $name and $wgSQLiteDataDir
+	 *   using $name and configured data directory
 	 * @param string $fname Calling function name
 	 * @return ResultWrapper
 	 */
 	function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
-		global $wgSQLiteDataDir;
 		if ( !$file ) {
-			$file = self::generateFileName( $wgSQLiteDataDir, $name );
+			$file = self::generateFileName( $this->dbDir, $name );
 		}
 		$file = $this->addQuotes( $file );
 
@@ -712,37 +750,14 @@ class DatabaseSqlite extends DatabaseBase {
 	}
 
 	protected function doBegin( $fname = '' ) {
-		if ( $this->mTrxLevel == 1 ) {
-			$this->commit( __METHOD__ );
-		}
-		try {
-			$this->mConn->beginTransaction();
-		} catch ( PDOException $e ) {
-			throw new DBUnexpectedError( $this, 'Error in BEGIN query: ' . $e->getMessage() );
+		if ( $this->trxMode ) {
+			$this->query( "BEGIN {$this->trxMode}", $fname );
+		} else {
+			$this->query( 'BEGIN', $fname );
 		}
 		$this->mTrxLevel = 1;
 	}
 
-	protected function doCommit( $fname = '' ) {
-		if ( $this->mTrxLevel == 0 ) {
-			return;
-		}
-		try {
-			$this->mConn->commit();
-		} catch ( PDOException $e ) {
-			throw new DBUnexpectedError( $this, 'Error in COMMIT query: ' . $e->getMessage() );
-		}
-		$this->mTrxLevel = 0;
-	}
-
-	protected function doRollback( $fname = '' ) {
-		if ( $this->mTrxLevel == 0 ) {
-			return;
-		}
-		$this->mConn->rollBack();
-		$this->mTrxLevel = 0;
-	}
-
 	/**
 	 * @param string $s
 	 * @return string
@@ -787,6 +802,10 @@ class DatabaseSqlite extends DatabaseBase {
 			// https://bugs.php.net/bug.php?id=63419
 			// There was already a similar report for SQLite3::escapeString, bug #62361:
 			// https://bugs.php.net/bug.php?id=62361
+			// There is an additional bug regarding sorting this data after insert
+			// on older versions of sqlite shipped with ubuntu 12.04
+			// https://bugzilla.wikimedia.org/show_bug.cgi?id=72367
+			wfDebugLog( __CLASS__, __FUNCTION__ . ': Quoting value containing null byte. For consistency all binary data should have been first processed with self::encodeBlob()' );
 			return "x'" . bin2hex( $s ) . "'";
 		} else {
 			return $this->mConn->quote( $s );
@@ -882,11 +901,9 @@ class DatabaseSqlite extends DatabaseBase {
 	}
 
 	public function lock( $lockName, $method, $timeout = 5 ) {
-		global $wgSQLiteDataDir;
-
-		if ( !is_dir( "$wgSQLiteDataDir/locks" ) ) { // create dir as needed
-			if ( !is_writable( $wgSQLiteDataDir ) || !mkdir( "$wgSQLiteDataDir/locks" ) ) {
-				throw new DBError( "Cannot create directory \"$wgSQLiteDataDir/locks\"." );
+		if ( !is_dir( "{$this->dbDir}/locks" ) ) { // create dir as needed
+			if ( !is_writable( $this->dbDir ) || !mkdir( "{$this->dbDir}/locks" ) ) {
+				throw new DBError( "Cannot create directory \"{$this->dbDir}/locks\"." );
 			}
 		}
 
@@ -981,18 +998,6 @@ class DatabaseSqlite extends DatabaseBase {
 } // end DatabaseSqlite class
 
 /**
- * This class allows simple acccess to a SQLite database independently from main database settings
- * @ingroup Database
- */
-class DatabaseSqliteStandalone extends DatabaseSqlite {
-	public function __construct( $fileName, $flags = 0 ) {
-		$this->mFlags = $flags;
-		$this->tablePrefix( null );
-		$this->openFile( $fileName );
-	}
-}
-
-/**
  * @ingroup Database
  */
 class SQLiteField implements Field {
diff --git a/includes/db/DatabaseUtility.php b/includes/db/DatabaseUtility.php
index c1e80d33..9a520ff9 100644
--- a/includes/db/DatabaseUtility.php
+++ b/includes/db/DatabaseUtility.php
@@ -22,29 +22,6 @@
  */
 
 /**
- * Utility class.
- * @ingroup Database
- */
-class DBObject {
-	public $mData;
-
-	function __construct( $data ) {
-		$this->mData = $data;
-	}
-
-	/**
-	 * @return bool
-	 */
-	function isLOB() {
-		return false;
-	}
-
-	function data() {
-		return $this->mData;
-	}
-}
-
-/**
  * Utility class
  * @ingroup Database
  *
@@ -339,4 +316,8 @@ class LikeMatch {
  * The implementation details of this opaque type are up to the database subclass.
  */
 interface DBMasterPos {
+	/**
+	 * @return float UNIX timestamp
+	 */
+	public function asOfTime();
 }
diff --git a/includes/db/IORMTable.php b/includes/db/IORMTable.php
index 4dc693ac..b2527f95 100644
--- a/includes/db/IORMTable.php
+++ b/includes/db/IORMTable.php
@@ -94,7 +94,7 @@ interface IORMTable {
 	public function getSummaryFields();
 
 	/**
-	 * Selects the the specified fields of the records matching the provided
+	 * Selects the specified fields of the records matching the provided
 	 * conditions and returns them as DBDataObject. Field names get prefixed.
 	 *
 	 * @see DatabaseBase::select()
@@ -113,7 +113,7 @@ interface IORMTable {
 		array $options = array(), $functionName = null );
 
 	/**
-	 * Selects the the specified fields of the records matching the provided
+	 * Selects the specified fields of the records matching the provided
 	 * conditions and returns them as DBDataObject. Field names get prefixed.
 	 *
 	 * @since 1.20
@@ -145,7 +145,7 @@ interface IORMTable {
 		array $options = array(), $functionName = null );
 
 	/**
-	 * Selects the the specified fields of the records matching the provided
+	 * Selects the specified fields of the records matching the provided
 	 * conditions and returns them as associative arrays.
 	 * Provided field names get prefixed.
 	 * Returned field names will not have a prefix.
@@ -170,7 +170,7 @@ interface IORMTable {
 		array $options = array(), $collapse = true, $functionName = null );
 
 	/**
-	 * Selects the the specified fields of the first matching record.
+	 * Selects the specified fields of the first matching record.
 	 * Field names get prefixed.
 	 *
 	 * @since 1.20
@@ -186,7 +186,7 @@ interface IORMTable {
 		array $options = array(), $functionName = null );
 
 	/**
-	 * Selects the the specified fields of the records matching the provided
+	 * Selects the specified fields of the records matching the provided
 	 * conditions. Field names do NOT get prefixed.
 	 *
 	 * @since 1.20
@@ -202,7 +202,7 @@ interface IORMTable {
 		array $options = array(), $functionName = null );
 
 	/**
-	 * Selects the the specified fields of the first record matching the provided
+	 * Selects the specified fields of the first record matching the provided
 	 * conditions and returns it as an associative array, or false when nothing matches.
 	 * This method makes use of selectFields and expects the same parameters and
 	 * returns the same results (if there are any, if there are none, this method returns false).
@@ -442,10 +442,11 @@ interface IORMTable {
 	 * Takes an array of field names with prefix and returns the unprefixed equivalent.
 	 *
 	 * @since 1.20
+	 * @deprecated since 1.25, will be removed
 	 *
-	 * @param array $fieldNames
+	 * @param string[] $fieldNames
 	 *
-	 * @return array
+	 * @return string[]
 	 */
 	public function unprefixFieldNames( array $fieldNames );
 
@@ -453,6 +454,7 @@ interface IORMTable {
 	 * Takes a field name with prefix and returns the unprefixed equivalent.
 	 *
 	 * @since 1.20
+	 * @deprecated since 1.25, will be removed
 	 *
 	 * @param string $fieldName
 	 *
diff --git a/includes/db/LBFactory.php b/includes/db/LBFactory.php
index 73456e23..4551e2d7 100644
--- a/includes/db/LBFactory.php
+++ b/includes/db/LBFactory.php
@@ -27,7 +27,7 @@
  */
 abstract class LBFactory {
 	/** @var LBFactory */
-	protected static $instance;
+	private static $instance;
 
 	/**
 	 * Disables all access to the load balancer, will cause all database access
@@ -43,7 +43,7 @@ abstract class LBFactory {
 	 *
 	 * @return LBFactory
 	 */
-	static function &singleton() {
+	public static function singleton() {
 		global $wgLBFactoryConf;
 
 		if ( is_null( self::$instance ) ) {
@@ -87,7 +87,7 @@ abstract class LBFactory {
 	/**
 	 * Shut down, close connections and destroy the cached instance.
 	 */
-	static function destroyInstance() {
+	public static function destroyInstance() {
 		if ( self::$instance ) {
 			self::$instance->shutdown();
 			self::$instance->forEachLBCallMethod( 'closeAll' );
@@ -100,7 +100,7 @@ abstract class LBFactory {
 	 *
 	 * @param LBFactory $instance
 	 */
-	static function setInstance( $instance ) {
+	public static function setInstance( $instance ) {
 		self::destroyInstance();
 		self::$instance = $instance;
 	}
@@ -109,7 +109,7 @@ abstract class LBFactory {
 	 * Construct a factory based on a configuration array (typically from $wgLBFactoryConf)
 	 * @param array $conf
 	 */
-	abstract function __construct( $conf );
+	abstract public function __construct( array $conf );
 
 	/**
 	 * Create a new load balancer object. The resulting object will be untracked,
@@ -118,7 +118,7 @@ abstract class LBFactory {
 	 * @param bool|string $wiki Wiki ID, or false for the current wiki
 	 * @return LoadBalancer
 	 */
-	abstract function newMainLB( $wiki = false );
+	abstract public function newMainLB( $wiki = false );
 
 	/**
 	 * Get a cached (tracked) load balancer object.
@@ -126,7 +126,7 @@ abstract class LBFactory {
 	 * @param bool|string $wiki Wiki ID, or false for the current wiki
 	 * @return LoadBalancer
 	 */
-	abstract function getMainLB( $wiki = false );
+	abstract public function getMainLB( $wiki = false );
 
 	/**
 	 * Create a new load balancer for external storage. The resulting object will be
@@ -137,7 +137,7 @@ abstract class LBFactory {
 	 * @param bool|string $wiki Wiki ID, or false for the current wiki
 	 * @return LoadBalancer
 	 */
-	abstract function newExternalLB( $cluster, $wiki = false );
+	abstract protected function newExternalLB( $cluster, $wiki = false );
 
 	/**
 	 * Get a cached (tracked) load balancer for external storage
@@ -146,7 +146,7 @@ abstract class LBFactory {
 	 * @param bool|string $wiki Wiki ID, or false for the current wiki
 	 * @return LoadBalancer
 	 */
-	abstract function &getExternalLB( $cluster, $wiki = false );
+	abstract public function &getExternalLB( $cluster, $wiki = false );
 
 	/**
 	 * Execute a function for each tracked load balancer
@@ -156,13 +156,13 @@ abstract class LBFactory {
 	 * @param callable $callback
 	 * @param array $params
 	 */
-	abstract function forEachLB( $callback, $params = array() );
+	abstract public function forEachLB( $callback, array $params = array() );
 
 	/**
 	 * Prepare all tracked load balancers for shutdown
 	 * STUB
 	 */
-	function shutdown() {
+	public function shutdown() {
 	}
 
 	/**
@@ -171,24 +171,16 @@ abstract class LBFactory {
 	 * @param string $methodName
 	 * @param array $args
 	 */
-	function forEachLBCallMethod( $methodName, $args = array() ) {
-		$this->forEachLB( array( $this, 'callMethod' ), array( $methodName, $args ) );
-	}
-
-	/**
-	 * Private helper for forEachLBCallMethod
-	 * @param LoadBalancer $loadBalancer
-	 * @param string $methodName
-	 * @param array $args
-	 */
-	function callMethod( $loadBalancer, $methodName, $args ) {
-		call_user_func_array( array( $loadBalancer, $methodName ), $args );
+	private function forEachLBCallMethod( $methodName, array $args = array() ) {
+		$this->forEachLB( function ( LoadBalancer $loadBalancer, $methodName, array $args ) {
+			call_user_func_array( array( $loadBalancer, $methodName ), $args );
+		}, array( $methodName, $args ) );
 	}
 
 	/**
 	 * Commit changes on all master connections
 	 */
-	function commitMasterChanges() {
+	public function commitMasterChanges() {
 		$this->forEachLBCallMethod( 'commitMasterChanges' );
 	}
 
@@ -196,7 +188,7 @@ abstract class LBFactory {
 	 * Rollback changes on all master connections
 	 * @since 1.23
 	 */
-	function rollbackMasterChanges() {
+	public function rollbackMasterChanges() {
 		$this->forEachLBCallMethod( 'rollbackMasterChanges' );
 	}
 
@@ -205,7 +197,7 @@ abstract class LBFactory {
 	 * @since 1.23
 	 * @return bool
 	 */
-	function hasMasterChanges() {
+	public function hasMasterChanges() {
 		$ret = false;
 		$this->forEachLB( function ( $lb ) use ( &$ret ) {
 			$ret = $ret || $lb->hasMasterChanges();
@@ -219,15 +211,15 @@ abstract class LBFactory {
  */
 class LBFactorySimple extends LBFactory {
 	/** @var LoadBalancer */
-	protected $mainLB;
+	private $mainLB;
 
 	/** @var LoadBalancer[] */
-	protected $extLBs = array();
+	private $extLBs = array();
 
 	/** @var ChronologyProtector */
-	protected $chronProt;
+	private $chronProt;
 
-	function __construct( $conf ) {
+	public function __construct( array $conf ) {
 		$this->chronProt = new ChronologyProtector;
 	}
 
@@ -235,7 +227,7 @@ class LBFactorySimple extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return LoadBalancer
 	 */
-	function newMainLB( $wiki = false ) {
+	public function newMainLB( $wiki = false ) {
 		global $wgDBservers;
 		if ( $wgDBservers ) {
 			$servers = $wgDBservers;
@@ -274,7 +266,7 @@ class LBFactorySimple extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return LoadBalancer
 	 */
-	function getMainLB( $wiki = false ) {
+	public function getMainLB( $wiki = false ) {
 		if ( !isset( $this->mainLB ) ) {
 			$this->mainLB = $this->newMainLB( $wiki );
 			$this->mainLB->parentInfo( array( 'id' => 'main' ) );
@@ -290,7 +282,7 @@ class LBFactorySimple extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return LoadBalancer
 	 */
-	function newExternalLB( $cluster, $wiki = false ) {
+	protected function newExternalLB( $cluster, $wiki = false ) {
 		global $wgExternalServers;
 		if ( !isset( $wgExternalServers[$cluster] ) ) {
 			throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
@@ -306,7 +298,7 @@ class LBFactorySimple extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return array
 	 */
-	function &getExternalLB( $cluster, $wiki = false ) {
+	public function &getExternalLB( $cluster, $wiki = false ) {
 		if ( !isset( $this->extLBs[$cluster] ) ) {
 			$this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki );
 			$this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
@@ -324,7 +316,7 @@ class LBFactorySimple extends LBFactory {
 	 * @param callable $callback
 	 * @param array $params
 	 */
-	function forEachLB( $callback, $params = array() ) {
+	public function forEachLB( $callback, array $params = array() ) {
 		if ( isset( $this->mainLB ) ) {
 			call_user_func_array( $callback, array_merge( array( $this->mainLB ), $params ) );
 		}
@@ -333,7 +325,7 @@ class LBFactorySimple extends LBFactory {
 		}
 	}
 
-	function shutdown() {
+	public function shutdown() {
 		if ( $this->mainLB ) {
 			$this->chronProt->shutdownLB( $this->mainLB );
 		}
@@ -352,26 +344,26 @@ class LBFactorySimple extends LBFactory {
  * LBFactory::enableBackend() to return to normal behavior
  */
 class LBFactoryFake extends LBFactory {
-	function __construct( $conf ) {
+	public function __construct( array $conf ) {
 	}
 
-	function newMainLB( $wiki = false ) {
+	public function newMainLB( $wiki = false ) {
 		throw new DBAccessError;
 	}
 
-	function getMainLB( $wiki = false ) {
+	public function getMainLB( $wiki = false ) {
 		throw new DBAccessError;
 	}
 
-	function newExternalLB( $cluster, $wiki = false ) {
+	protected function newExternalLB( $cluster, $wiki = false ) {
 		throw new DBAccessError;
 	}
 
-	function &getExternalLB( $cluster, $wiki = false ) {
+	public function &getExternalLB( $cluster, $wiki = false ) {
 		throw new DBAccessError;
 	}
 
-	function forEachLB( $callback, $params = array() ) {
+	public function forEachLB( $callback, array $params = array() ) {
 	}
 }
 
@@ -379,7 +371,7 @@ class LBFactoryFake extends LBFactory {
  * Exception class for attempted DB access
  */
 class DBAccessError extends MWException {
-	function __construct() {
+	public function __construct() {
 		parent::__construct( "Mediawiki tried to access the database via wfGetDB(). " .
 			"This is not allowed." );
 	}
diff --git a/includes/db/LBFactoryMulti.php b/includes/db/LBFactoryMulti.php
index bac96523..aa305ab1 100644
--- a/includes/db/LBFactoryMulti.php
+++ b/includes/db/LBFactoryMulti.php
@@ -77,82 +77,82 @@ class LBFactoryMulti extends LBFactory {
 	// Required settings
 
 	/** @var array A map of database names to section names */
-	protected $sectionsByDB;
+	private $sectionsByDB;
 
 	/**
 	 * @var array A 2-d map. For each section, gives a map of server names to
 	 * load ratios
 	 */
-	protected $sectionLoads;
+	private $sectionLoads;
 
 	/**
 	 * @var array A server info associative array as documented for
 	 * $wgDBservers. The host, hostName and load entries will be
 	 * overridden
 	 */
-	protected $serverTemplate;
+	private $serverTemplate;
 
 	// Optional settings
 
 	/** @var array A 3-d map giving server load ratios for each section and group */
-	protected $groupLoadsBySection = array();
+	private $groupLoadsBySection = array();
 
 	/** @var array A 3-d map giving server load ratios by DB name */
-	protected $groupLoadsByDB = array();
+	private $groupLoadsByDB = array();
 
 	/** @var array A map of hostname to IP address */
-	protected $hostsByName = array();
+	private $hostsByName = array();
 
 	/** @var array A map of external storage cluster name to server load map */
-	protected $externalLoads = array();
+	private $externalLoads = array();
 
 	/**
 	 * @var array A set of server info keys overriding serverTemplate for
 	 * external storage
 	 */
-	protected $externalTemplateOverrides;
+	private $externalTemplateOverrides;
 
 	/**
 	 * @var array A 2-d map overriding serverTemplate and
 	 * externalTemplateOverrides on a server-by-server basis. Applies to both
 	 * core and external storage
 	 */
-	protected $templateOverridesByServer;
+	private $templateOverridesByServer;
 
 	/** @var array A 2-d map overriding the server info by external storage cluster */
-	protected $templateOverridesByCluster;
+	private $templateOverridesByCluster;
 
 	/** @var array An override array for all master servers */
-	protected $masterTemplateOverrides;
+	private $masterTemplateOverrides;
 
 	/**
 	 * @var array|bool A map of section name to read-only message. Missing or
 	 * false for read/write
 	 */
-	protected $readOnlyBySection = array();
+	private $readOnlyBySection = array();
 
 	// Other stuff
 
 	/** @var array Load balancer factory configuration */
-	protected $conf;
+	private $conf;
 
 	/** @var LoadBalancer[] */
-	protected $mainLBs = array();
+	private $mainLBs = array();
 
 	/** @var LoadBalancer[] */
-	protected $extLBs = array();
+	private $extLBs = array();
 
 	/** @var string */
-	protected $lastWiki;
+	private $lastWiki;
 
 	/** @var string */
-	protected $lastSection;
+	private $lastSection;
 
 	/**
 	 * @param array $conf
 	 * @throws MWException
 	 */
-	function __construct( $conf ) {
+	public function __construct( array $conf ) {
 		$this->chronProt = new ChronologyProtector;
 		$this->conf = $conf;
 		$required = array( 'sectionsByDB', 'sectionLoads', 'serverTemplate' );
@@ -186,7 +186,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return string
 	 */
-	function getSectionForWiki( $wiki = false ) {
+	private function getSectionForWiki( $wiki = false ) {
 		if ( $this->lastWiki === $wiki ) {
 			return $this->lastSection;
 		}
@@ -206,7 +206,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return LoadBalancer
 	 */
-	function newMainLB( $wiki = false ) {
+	public function newMainLB( $wiki = false ) {
 		list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
 		$section = $this->getSectionForWiki( $wiki );
 		$groupLoads = array();
@@ -229,7 +229,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return LoadBalancer
 	 */
-	function getMainLB( $wiki = false ) {
+	public function getMainLB( $wiki = false ) {
 		$section = $this->getSectionForWiki( $wiki );
 		if ( !isset( $this->mainLBs[$section] ) ) {
 			$lb = $this->newMainLB( $wiki, $section );
@@ -247,7 +247,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @throws MWException
 	 * @return LoadBalancer
 	 */
-	function newExternalLB( $cluster, $wiki = false ) {
+	protected function newExternalLB( $cluster, $wiki = false ) {
 		if ( !isset( $this->externalLoads[$cluster] ) ) {
 			throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
 		}
@@ -267,7 +267,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param bool|string $wiki Wiki ID, or false for the current wiki
 	 * @return LoadBalancer
 	 */
-	function &getExternalLB( $cluster, $wiki = false ) {
+	public function &getExternalLB( $cluster, $wiki = false ) {
 		if ( !isset( $this->extLBs[$cluster] ) ) {
 			$this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki );
 			$this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
@@ -285,7 +285,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param array $groupLoads
 	 * @return LoadBalancer
 	 */
-	function newLoadBalancer( $template, $loads, $groupLoads ) {
+	private function newLoadBalancer( $template, $loads, $groupLoads ) {
 		$servers = $this->makeServerArray( $template, $loads, $groupLoads );
 		$lb = new LoadBalancer( array(
 			'servers' => $servers,
@@ -302,7 +302,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param array $groupLoads
 	 * @return array
 	 */
-	function makeServerArray( $template, $loads, $groupLoads ) {
+	private function makeServerArray( $template, $loads, $groupLoads ) {
 		$servers = array();
 		$master = true;
 		$groupLoadsByServer = $this->reindexGroupLoads( $groupLoads );
@@ -344,7 +344,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param array $groupLoads
 	 * @return array
 	 */
-	function reindexGroupLoads( $groupLoads ) {
+	private function reindexGroupLoads( $groupLoads ) {
 		$reindexed = array();
 		foreach ( $groupLoads as $group => $loads ) {
 			foreach ( $loads as $server => $load ) {
@@ -360,7 +360,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return array
 	 */
-	function getDBNameAndPrefix( $wiki = false ) {
+	private function getDBNameAndPrefix( $wiki = false ) {
 		if ( $wiki === false ) {
 			global $wgDBname, $wgDBprefix;
 
@@ -377,7 +377,7 @@ class LBFactoryMulti extends LBFactory {
 	 * @param callable $callback
 	 * @param array $params
 	 */
-	function forEachLB( $callback, $params = array() ) {
+	public function forEachLB( $callback, array $params = array() ) {
 		foreach ( $this->mainLBs as $lb ) {
 			call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
 		}
@@ -386,7 +386,7 @@ class LBFactoryMulti extends LBFactory {
 		}
 	}
 
-	function shutdown() {
+	public function shutdown() {
 		foreach ( $this->mainLBs as $lb ) {
 			$this->chronProt->shutdownLB( $lb );
 		}
diff --git a/includes/db/LBFactorySingle.php b/includes/db/LBFactorySingle.php
index 3a4d829b..a41dadfa 100644
--- a/includes/db/LBFactorySingle.php
+++ b/includes/db/LBFactorySingle.php
@@ -26,13 +26,13 @@
  */
 class LBFactorySingle extends LBFactory {
 	/** @var LoadBalancerSingle */
-	protected $lb;
+	private $lb;
 
 	/**
 	 * @param array $conf An associative array with one member:
 	 *  - connection: The DatabaseBase connection object
 	 */
-	function __construct( $conf ) {
+	public function __construct( array $conf ) {
 		$this->lb = new LoadBalancerSingle( $conf );
 	}
 
@@ -40,7 +40,7 @@ class LBFactorySingle extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return LoadBalancerSingle
 	 */
-	function newMainLB( $wiki = false ) {
+	public function newMainLB( $wiki = false ) {
 		return $this->lb;
 	}
 
@@ -48,7 +48,7 @@ class LBFactorySingle extends LBFactory {
 	 * @param bool|string $wiki
 	 * @return LoadBalancerSingle
 	 */
-	function getMainLB( $wiki = false ) {
+	public function getMainLB( $wiki = false ) {
 		return $this->lb;
 	}
 
@@ -57,7 +57,7 @@ class LBFactorySingle extends LBFactory {
 	 * @param bool|string $wiki Wiki ID, or false for the current wiki
 	 * @return LoadBalancerSingle
 	 */
-	function newExternalLB( $cluster, $wiki = false ) {
+	protected function newExternalLB( $cluster, $wiki = false ) {
 		return $this->lb;
 	}
 
@@ -66,7 +66,7 @@ class LBFactorySingle extends LBFactory {
 	 * @param bool|string $wiki Wiki ID, or false for the current wiki
 	 * @return LoadBalancerSingle
 	 */
-	function &getExternalLB( $cluster, $wiki = false ) {
+	public function &getExternalLB( $cluster, $wiki = false ) {
 		return $this->lb;
 	}
 
@@ -74,7 +74,7 @@ class LBFactorySingle extends LBFactory {
 	 * @param string|callable $callback
 	 * @param array $params
 	 */
-	function forEachLB( $callback, $params = array() ) {
+	public function forEachLB( $callback, array $params = array() ) {
 		call_user_func_array( $callback, array_merge( array( $this->lb ), $params ) );
 	}
 }
@@ -84,12 +84,12 @@ class LBFactorySingle extends LBFactory {
  */
 class LoadBalancerSingle extends LoadBalancer {
 	/** @var DatabaseBase */
-	protected $db;
+	private $db;
 
 	/**
 	 * @param array $params
 	 */
-	function __construct( $params ) {
+	public function __construct( array $params ) {
 		$this->db = $params['connection'];
 		parent::__construct( array( 'servers' => array( array(
 			'type' => $this->db->getType(),
@@ -106,7 +106,7 @@ class LoadBalancerSingle extends LoadBalancer {
 	 *
 	 * @return DatabaseBase
 	 */
-	function reallyOpenConnection( $server, $dbNameOverride = false ) {
+	protected function reallyOpenConnection( $server, $dbNameOverride = false ) {
 		return $this->db;
 	}
 }
diff --git a/includes/db/LoadBalancer.php b/includes/db/LoadBalancer.php
index e517a025..d9584e14 100644
--- a/includes/db/LoadBalancer.php
+++ b/includes/db/LoadBalancer.php
@@ -28,13 +28,13 @@
  * @ingroup Database
  */
 class LoadBalancer {
-	/** @var array Map of (server index => server config array) */
+	/** @var array[] Map of (server index => server config array) */
 	private $mServers;
-	/** @var array Map of (local/foreignUsed/foreignFree => server index => DatabaseBase array) */
+	/** @var array[] Map of (local/foreignUsed/foreignFree => server index => DatabaseBase array) */
 	private $mConns;
 	/** @var array Map of (server index => weight) */
 	private $mLoads;
-	/** @var array Map of (group => server index => weight) */
+	/** @var array[] Map of (group => server index => weight) */
 	private $mGroupLoads;
 	/** @var bool Whether to disregard slave lag as a factor in slave selection */
 	private $mAllowLagged;
@@ -58,8 +58,13 @@ class LoadBalancer {
 	private $mLaggedSlaveMode;
 	/** @var string The last DB selection or connection error */
 	private $mLastError = 'Unknown error';
-	/** @var array Process cache of LoadMonitor::getLagTimes() */
-	private $mLagTimes;
+	/** @var integer Total connections opened */
+	private $connsOpened = 0;
+	/** @var ProcessCacheLRU */
+	private $mProcCache;
+
+	/** @var integer Warn when this many connection are held */
+	const CONN_HELD_WARN_THRESHOLD = 10;
 
 	/**
 	 * @param array $params Array with keys:
@@ -67,7 +72,7 @@ class LoadBalancer {
 	 *   loadMonitor       Name of a class used to fetch server lag and load.
 	 * @throws MWException
 	 */
-	function __construct( $params ) {
+	public function __construct( array $params ) {
 		if ( !isset( $params['servers'] ) ) {
 			throw new MWException( __CLASS__ . ': missing servers parameter' );
 		}
@@ -108,6 +113,8 @@ class LoadBalancer {
 				}
 			}
 		}
+
+		$this->mProcCache = new ProcessCacheLRU( 30 );
 	}
 
 	/**
@@ -115,7 +122,7 @@ class LoadBalancer {
 	 *
 	 * @return LoadMonitor
 	 */
-	function getLoadMonitor() {
+	private function getLoadMonitor() {
 		if ( !isset( $this->mLoadMonitor ) ) {
 			$class = $this->mLoadMonitorClass;
 			$this->mLoadMonitor = new $class( $this );
@@ -129,7 +136,7 @@ class LoadBalancer {
 	 * @param mixed $x
 	 * @return mixed
 	 */
-	function parentInfo( $x = null ) {
+	public function parentInfo( $x = null ) {
 		return wfSetVar( $this->mParentInfo, $x );
 	}
 
@@ -142,24 +149,30 @@ class LoadBalancer {
 	 * @param array $weights
 	 * @return bool|int|string
 	 */
-	function pickRandom( $weights ) {
+	public function pickRandom( array $weights ) {
 		return ArrayUtils::pickRandom( $weights );
 	}
 
 	/**
 	 * @param array $loads
 	 * @param bool|string $wiki Wiki to get non-lagged for
+	 * @param float $maxLag Restrict the maximum allowed lag to this many seconds
 	 * @return bool|int|string
 	 */
-	function getRandomNonLagged( $loads, $wiki = false ) {
-		# Unset excessively lagged servers
+	private function getRandomNonLagged( array $loads, $wiki = false, $maxLag = INF ) {
 		$lags = $this->getLagTimes( $wiki );
+
+		# Unset excessively lagged servers
 		foreach ( $lags as $i => $lag ) {
 			if ( $i != 0 ) {
+				$maxServerLag = $maxLag;
+				if ( isset( $this->mServers[$i]['max lag'] ) ) {
+					$maxServerLag = min( $maxServerLag, $this->mServers[$i]['max lag'] );
+				}
 				if ( $lag === false ) {
 					wfDebugLog( 'replication', "Server #$i is not replicating" );
 					unset( $loads[$i] );
-				} elseif ( isset( $this->mServers[$i]['max lag'] ) && $lag > $this->mServers[$i]['max lag'] ) {
+				} elseif ( $lag > $maxServerLag ) {
 					wfDebugLog( 'replication', "Server #$i is excessively lagged ($lag seconds)" );
 					unset( $loads[$i] );
 				}
@@ -195,12 +208,12 @@ class LoadBalancer {
 	 * always return a consistent index during a given invocation
 	 *
 	 * Side effect: opens connections to databases
-	 * @param bool|string $group
-	 * @param bool|string $wiki
+	 * @param string|bool $group Query group, or false for the generic reader
+	 * @param string|bool $wiki Wiki ID, or false for the current wiki
 	 * @throws MWException
 	 * @return bool|int|string
 	 */
-	function getReaderIndex( $group = false, $wiki = false ) {
+	public function getReaderIndex( $group = false, $wiki = false ) {
 		global $wgReadOnly, $wgDBtype;
 
 		# @todo FIXME: For now, only go through all this for mysql databases
@@ -216,8 +229,6 @@ class LoadBalancer {
 			return $this->mReadIndex;
 		}
 
-		$section = new ProfileSection( __METHOD__ );
-
 		# Find the relevant load array
 		if ( $group !== false ) {
 			if ( isset( $this->mGroupLoads[$group] ) ) {
@@ -250,7 +261,19 @@ class LoadBalancer {
 			if ( $wgReadOnly || $this->mAllowLagged || $laggedSlaveMode ) {
 				$i = ArrayUtils::pickRandom( $currentLoads );
 			} else {
-				$i = $this->getRandomNonLagged( $currentLoads, $wiki );
+				$i = false;
+				if ( $this->mWaitForPos && $this->mWaitForPos->asOfTime() ) {
+					# ChronologyProtecter causes mWaitForPos to be set via sessions.
+					# This triggers doWait() after connect, so it's especially good to
+					# avoid lagged servers so as to avoid just blocking in that method.
+					$ago = microtime( true ) - $this->mWaitForPos->asOfTime();
+					# Aim for <= 1 second of waiting (being too picky can backfire)
+					$i = $this->getRandomNonLagged( $currentLoads, $wiki, $ago + 1 );
+				}
+				if ( $i === false ) {
+					# Any server with less lag than it's 'max lag' param is preferable
+					$i = $this->getRandomNonLagged( $currentLoads, $wiki );
+				}
 				if ( $i === false && count( $currentLoads ) != 0 ) {
 					# All slaves lagged. Switch to read-only mode
 					wfDebugLog( 'replication', "All slaves lagged. Switch to read-only mode" );
@@ -305,36 +328,23 @@ class LoadBalancer {
 					$this->mServers[$i]['slave pos'] = $conn->getSlavePos();
 				}
 			}
-			if ( $this->mReadIndex <= 0 && $this->mLoads[$i] > 0 && $group !== false ) {
+			if ( $this->mReadIndex <= 0 && $this->mLoads[$i] > 0 && $group === false ) {
 				$this->mReadIndex = $i;
 			}
+			$serverName = $this->getServerName( $i );
+			wfDebug( __METHOD__ . ": using server $serverName for group '$group'\n" );
 		}
 
 		return $i;
 	}
 
 	/**
-	 * Wait for a specified number of microseconds, and return the period waited
-	 * @param int $t
-	 * @return int
-	 */
-	function sleep( $t ) {
-		wfProfileIn( __METHOD__ );
-		wfDebug( __METHOD__ . ": waiting $t us\n" );
-		usleep( $t );
-		wfProfileOut( __METHOD__ );
-
-		return $t;
-	}
-
-	/**
 	 * Set the master wait position
 	 * If a DB_SLAVE connection has been opened already, waits
 	 * Otherwise sets a variable telling it to wait if such a connection is opened
 	 * @param DBMasterPos $pos
 	 */
 	public function waitFor( $pos ) {
-		wfProfileIn( __METHOD__ );
 		$this->mWaitForPos = $pos;
 		$i = $this->mReadIndex;
 
@@ -344,7 +354,6 @@ class LoadBalancer {
 				$this->mLaggedSlaveMode = true;
 			}
 		}
-		wfProfileOut( __METHOD__ );
 	}
 
 	/**
@@ -354,7 +363,6 @@ class LoadBalancer {
 	 * @return bool Success (able to connect and no timeouts reached)
 	 */
 	public function waitForAll( $pos, $timeout = null ) {
-		wfProfileIn( __METHOD__ );
 		$this->mWaitForPos = $pos;
 		$serverCount = count( $this->mServers );
 
@@ -364,7 +372,6 @@ class LoadBalancer {
 				$ok = $this->doWait( $i, true, $timeout ) && $ok;
 			}
 		}
-		wfProfileOut( __METHOD__ );
 
 		return $ok;
 	}
@@ -376,7 +383,7 @@ class LoadBalancer {
 	 * @param int $i
 	 * @return DatabaseBase|bool False on failure
 	 */
-	function getAnyOpenConnection( $i ) {
+	public function getAnyOpenConnection( $i ) {
 		foreach ( $this->mConns as $conns ) {
 			if ( !empty( $conns[$i] ) ) {
 				return reset( $conns[$i] );
@@ -394,7 +401,9 @@ class LoadBalancer {
 	 * @return bool
 	 */
 	protected function doWait( $index, $open = false, $timeout = null ) {
-		# Find a connection to wait on
+		$close = false; // close the connection afterwards
+
+		# Find a connection to wait on, creating one if needed and allowed
 		$conn = $this->getAnyOpenConnection( $index );
 		if ( !$conn ) {
 			if ( !$open ) {
@@ -408,6 +417,9 @@ class LoadBalancer {
 
 					return false;
 				}
+				// Avoid connection spam in waitForAll() when connections
+				// are made just for the sake of doing this lag check.
+				$close = true;
 			}
 		}
 
@@ -417,14 +429,21 @@ class LoadBalancer {
 
 		if ( $result == -1 || is_null( $result ) ) {
 			# Timed out waiting for slave, use master instead
-			wfDebug( __METHOD__ . ": Timed out waiting for slave #$index pos {$this->mWaitForPos}\n" );
-
-			return false;
+			$server = $this->mServers[$index]['host'];
+			$msg = __METHOD__ . ": Timed out waiting on $server pos {$this->mWaitForPos}";
+			wfDebug( "$msg\n" );
+			wfDebugLog( 'DBPerformance', "$msg:\n" . wfBacktrace( true ) );
+			$ok = false;
 		} else {
 			wfDebug( __METHOD__ . ": Done\n" );
+			$ok = true;
+		}
 
-			return true;
+		if ( $close ) {
+			$this->closeConnection( $conn );
 		}
+
+		return $ok;
 	}
 
 	/**
@@ -432,17 +451,14 @@ class LoadBalancer {
 	 * This is the main entry point for this class.
 	 *
 	 * @param int $i Server index
-	 * @param array $groups Query groups
-	 * @param bool|string $wiki Wiki ID
+	 * @param array|string|bool $groups Query group(s), or false for the generic reader
+	 * @param string|bool $wiki Wiki ID, or false for the current wiki
 	 *
 	 * @throws MWException
 	 * @return DatabaseBase
 	 */
-	public function &getConnection( $i, $groups = array(), $wiki = false ) {
-		wfProfileIn( __METHOD__ );
-
+	public function getConnection( $i, $groups = array(), $wiki = false ) {
 		if ( $i === null || $i === false ) {
-			wfProfileOut( __METHOD__ );
 			throw new MWException( 'Attempt to call ' . __METHOD__ .
 				' with invalid server index' );
 		}
@@ -451,22 +467,20 @@ class LoadBalancer {
 			$wiki = false;
 		}
 
-		# Query groups
+		$groups = ( $groups === false || $groups === array() )
+			? array( false ) // check one "group": the generic pool
+			: (array)$groups;
+
+		$masterOnly = ( $i == DB_MASTER || $i == $this->getWriterIndex() );
+		$oldConnsOpened = $this->connsOpened; // connections open now
+
 		if ( $i == DB_MASTER ) {
 			$i = $this->getWriterIndex();
-		} elseif ( !is_array( $groups ) ) {
-			$groupIndex = $this->getReaderIndex( $groups, $wiki );
-			if ( $groupIndex !== false ) {
-				$serverName = $this->getServerName( $groupIndex );
-				wfDebug( __METHOD__ . ": using server $serverName for group $groups\n" );
-				$i = $groupIndex;
-			}
 		} else {
+			# Try to find an available server in any the query groups (in order)
 			foreach ( $groups as $group ) {
 				$groupIndex = $this->getReaderIndex( $group, $wiki );
 				if ( $groupIndex !== false ) {
-					$serverName = $this->getServerName( $groupIndex );
-					wfDebug( __METHOD__ . ": using server $serverName for group $group\n" );
 					$i = $groupIndex;
 					break;
 				}
@@ -476,11 +490,13 @@ class LoadBalancer {
 		# Operation-based index
 		if ( $i == DB_SLAVE ) {
 			$this->mLastError = 'Unknown error'; // reset error string
-			$i = $this->getReaderIndex( false, $wiki );
+			# Try the general server pool if $groups are unavailable.
+			$i = in_array( false, $groups, true )
+				? false // don't bother with this if that is what was tried above
+				: $this->getReaderIndex( false, $wiki );
 			# Couldn't find a working server in getReaderIndex()?
 			if ( $i === false ) {
 				$this->mLastError = 'No working slave server: ' . $this->mLastError;
-				wfProfileOut( __METHOD__ );
 
 				return $this->reportConnectionError();
 			}
@@ -489,12 +505,17 @@ class LoadBalancer {
 		# Now we have an explicit index into the servers array
 		$conn = $this->openConnection( $i, $wiki );
 		if ( !$conn ) {
-			wfProfileOut( __METHOD__ );
 
 			return $this->reportConnectionError();
 		}
 
-		wfProfileOut( __METHOD__ );
+		# Profile any new connections that happen
+		if ( $this->connsOpened > $oldConnsOpened ) {
+			$host = $conn->getServer();
+			$dbname = $conn->getDBname();
+			$trxProf = Profiler::instance()->getTransactionProfiler();
+			$trxProf->recordConnection( $host, $dbname, $masterOnly );
+		}
 
 		return $conn;
 	}
@@ -556,8 +577,8 @@ class LoadBalancer {
 	 * @see LoadBalancer::getConnection() for parameter information
 	 *
 	 * @param int $db
-	 * @param mixed $groups
-	 * @param bool|string $wiki
+	 * @param array|string|bool $groups Query group(s), or false for the generic reader
+	 * @param string|bool $wiki Wiki ID, or false for the current wiki
 	 * @return DBConnRef
 	 */
 	public function getConnectionRef( $db, $groups = array(), $wiki = false ) {
@@ -572,8 +593,8 @@ class LoadBalancer {
 	 * @see LoadBalancer::getConnection() for parameter information
 	 *
 	 * @param int $db
-	 * @param mixed $groups
-	 * @param bool|string $wiki
+	 * @param array|string|bool $groups Query group(s), or false for the generic reader
+	 * @param string|bool $wiki Wiki ID, or false for the current wiki
 	 * @return DBConnRef
 	 */
 	public function getLazyConnectionRef( $db, $groups = array(), $wiki = false ) {
@@ -589,16 +610,14 @@ class LoadBalancer {
 	 * error will be available via $this->mErrorConnection.
 	 *
 	 * @param int $i Server index
-	 * @param bool|string $wiki Wiki ID to open
+	 * @param string|bool $wiki Wiki ID, or false for the current wiki
 	 * @return DatabaseBase
 	 *
 	 * @access private
 	 */
-	function openConnection( $i, $wiki = false ) {
-		wfProfileIn( __METHOD__ );
+	public function openConnection( $i, $wiki = false ) {
 		if ( $wiki !== false ) {
 			$conn = $this->openForeignConnection( $i, $wiki );
-			wfProfileOut( __METHOD__ );
 
 			return $conn;
 		}
@@ -617,7 +636,6 @@ class LoadBalancer {
 				$conn = false;
 			}
 		}
-		wfProfileOut( __METHOD__ );
 
 		return $conn;
 	}
@@ -640,8 +658,7 @@ class LoadBalancer {
 	 * @param string $wiki Wiki ID to open
 	 * @return DatabaseBase
 	 */
-	function openForeignConnection( $i, $wiki ) {
-		wfProfileIn( __METHOD__ );
+	private function openForeignConnection( $i, $wiki ) {
 		list( $dbName, $prefix ) = wfSplitWikiID( $wiki );
 		if ( isset( $this->mConns['foreignUsed'][$i][$wiki] ) ) {
 			// Reuse an already-used connection
@@ -658,7 +675,9 @@ class LoadBalancer {
 			$conn = reset( $this->mConns['foreignFree'][$i] );
 			$oldWiki = key( $this->mConns['foreignFree'][$i] );
 
-			if ( !$conn->selectDB( $dbName ) ) {
+			// The empty string as a DB name means "don't care".
+			// DatabaseMysqlBase::open() already handle this on connection.
+			if ( $dbName !== '' && !$conn->selectDB( $dbName ) ) {
 				$this->mLastError = "Error selecting database $dbName on server " .
 					$conn->getServer() . " from client host " . wfHostname() . "\n";
 				$this->mErrorConnection = $conn;
@@ -692,7 +711,6 @@ class LoadBalancer {
 			$refCount = $conn->getLBInfo( 'foreignPoolRefCount' );
 			$conn->setLBInfo( 'foreignPoolRefCount', $refCount + 1 );
 		}
-		wfProfileOut( __METHOD__ );
 
 		return $conn;
 	}
@@ -704,7 +722,7 @@ class LoadBalancer {
 	 * @access private
 	 * @return bool
 	 */
-	function isOpen( $index ) {
+	private function isOpen( $index ) {
 		if ( !is_integer( $index ) ) {
 			return false;
 		}
@@ -722,7 +740,7 @@ class LoadBalancer {
 	 * @throws MWException
 	 * @return DatabaseBase
 	 */
-	function reallyOpenConnection( $server, $dbNameOverride = false ) {
+	protected function reallyOpenConnection( $server, $dbNameOverride = false ) {
 		if ( !is_array( $server ) ) {
 			throw new MWException( 'You must update your load-balancing configuration. ' .
 				'See DefaultSettings.php entry for $wgDBservers.' );
@@ -732,6 +750,14 @@ class LoadBalancer {
 			$server['dbname'] = $dbNameOverride;
 		}
 
+		// Log when many connection are made on requests
+		if ( ++$this->connsOpened >= self::CONN_HELD_WARN_THRESHOLD ) {
+			$masterAddr = $this->getServerName( 0 );
+			wfDebugLog( 'DBPerformance', __METHOD__ . ": " .
+				"{$this->connsOpened}+ connections made (master=$masterAddr)\n" .
+				wfBacktrace( true ) );
+		}
+
 		# Create object
 		try {
 			$db = DatabaseBase::factory( $server['type'], $server );
@@ -758,17 +784,27 @@ class LoadBalancer {
 	 */
 	private function reportConnectionError() {
 		$conn = $this->mErrorConnection; // The connection which caused the error
+		$context = array(
+			'method' => __METHOD__,
+			'last_error' => $this->mLastError,
+		);
 
 		if ( !is_object( $conn ) ) {
 			// No last connection, probably due to all servers being too busy
-			wfLogDBError( "LB failure with no last connection. Connection error: {$this->mLastError}" );
+			wfLogDBError(
+				"LB failure with no last connection. Connection error: {last_error}",
+				$context
+			);
 
 			// If all servers were busy, mLastError will contain something sensible
 			throw new DBConnectionError( null, $this->mLastError );
 		} else {
-			$server = $conn->getProperty( 'mServer' );
-			wfLogDBError( "Connection error: {$this->mLastError} ({$server})" );
-			$conn->reportConnectionError( "{$this->mLastError} ({$server})" ); // throws DBConnectionError
+			$context['db_server'] = $conn->getProperty( 'mServer' );
+			wfLogDBError(
+				"Connection error: {last_error} ({db_server})",
+				$context
+			);
+			$conn->reportConnectionError( "{$this->mLastError} ({$context['db_server']})" ); // throws DBConnectionError
 		}
 
 		return false; /* not reached */
@@ -777,7 +813,7 @@ class LoadBalancer {
 	/**
 	 * @return int
 	 */
-	function getWriterIndex() {
+	private function getWriterIndex() {
 		return 0;
 	}
 
@@ -787,7 +823,7 @@ class LoadBalancer {
 	 * @param string $i
 	 * @return bool
 	 */
-	function haveIndex( $i ) {
+	public function haveIndex( $i ) {
 		return array_key_exists( $i, $this->mServers );
 	}
 
@@ -797,7 +833,7 @@ class LoadBalancer {
 	 * @param string $i
 	 * @return bool
 	 */
-	function isNonZeroLoad( $i ) {
+	public function isNonZeroLoad( $i ) {
 		return array_key_exists( $i, $this->mServers ) && $this->mLoads[$i] != 0;
 	}
 
@@ -806,7 +842,7 @@ class LoadBalancer {
 	 *
 	 * @return int
 	 */
-	function getServerCount() {
+	public function getServerCount() {
 		return count( $this->mServers );
 	}
 
@@ -816,7 +852,7 @@ class LoadBalancer {
 	 * @param string $i
 	 * @return string
 	 */
-	function getServerName( $i ) {
+	public function getServerName( $i ) {
 		if ( isset( $this->mServers[$i]['hostName'] ) ) {
 			return $this->mServers[$i]['hostName'];
 		} elseif ( isset( $this->mServers[$i]['host'] ) ) {
@@ -831,7 +867,7 @@ class LoadBalancer {
 	 * @param int $i
 	 * @return array|bool
 	 */
-	function getServerInfo( $i ) {
+	public function getServerInfo( $i ) {
 		if ( isset( $this->mServers[$i] ) ) {
 			return $this->mServers[$i];
 		} else {
@@ -845,7 +881,7 @@ class LoadBalancer {
 	 * @param int $i
 	 * @param array $serverInfo
 	 */
-	function setServerInfo( $i, $serverInfo ) {
+	public function setServerInfo( $i, array $serverInfo ) {
 		$this->mServers[$i] = $serverInfo;
 	}
 
@@ -853,7 +889,7 @@ class LoadBalancer {
 	 * Get the current master position for chronology control purposes
 	 * @return mixed
 	 */
-	function getMasterPos() {
+	public function getMasterPos() {
 		# If this entire request was served from a slave without opening a connection to the
 		# master (however unlikely that may be), then we can fetch the position from the slave.
 		$masterConn = $this->getAnyOpenConnection( 0 );
@@ -879,7 +915,7 @@ class LoadBalancer {
 	/**
 	 * Close all open connections
 	 */
-	function closeAll() {
+	public function closeAll() {
 		foreach ( $this->mConns as $conns2 ) {
 			foreach ( $conns2 as $conns3 ) {
 				/** @var DatabaseBase $conn */
@@ -893,6 +929,7 @@ class LoadBalancer {
 			'foreignFree' => array(),
 			'foreignUsed' => array(),
 		);
+		$this->connsOpened = 0;
 	}
 
 	/**
@@ -901,7 +938,7 @@ class LoadBalancer {
 	 * If you use $conn->close() directly, the load balancer won't update its state.
 	 * @param DatabaseBase $conn
 	 */
-	function closeConnection( $conn ) {
+	public function closeConnection( $conn ) {
 		$done = false;
 		foreach ( $this->mConns as $i1 => $conns2 ) {
 			foreach ( $conns2 as $i2 => $conns3 ) {
@@ -909,6 +946,7 @@ class LoadBalancer {
 					if ( $conn === $candidateConn ) {
 						$conn->close();
 						unset( $this->mConns[$i1][$i2][$i3] );
+						--$this->connsOpened;
 						$done = true;
 						break;
 					}
@@ -923,7 +961,7 @@ class LoadBalancer {
 	/**
 	 * Commit transactions on all open connections
 	 */
-	function commitAll() {
+	public function commitAll() {
 		foreach ( $this->mConns as $conns2 ) {
 			foreach ( $conns2 as $conns3 ) {
 				/** @var DatabaseBase[] $conns3 */
@@ -939,8 +977,7 @@ class LoadBalancer {
 	/**
 	 *  Issue COMMIT only on master, only if queries were done on connection
 	 */
-	function commitMasterChanges() {
-		// Always 0, but who knows.. :)
+	public function commitMasterChanges() {
 		$masterIndex = $this->getWriterIndex();
 		foreach ( $this->mConns as $conns2 ) {
 			if ( empty( $conns2[$masterIndex] ) ) {
@@ -959,8 +996,9 @@ class LoadBalancer {
 	 * Issue ROLLBACK only on master, only if queries were done on connection
 	 * @since 1.23
 	 */
-	function rollbackMasterChanges() {
-		// Always 0, but who knows.. :)
+	public function rollbackMasterChanges() {
+		$failedServers = array();
+
 		$masterIndex = $this->getWriterIndex();
 		foreach ( $this->mConns as $conns2 ) {
 			if ( empty( $conns2[$masterIndex] ) ) {
@@ -969,28 +1007,36 @@ class LoadBalancer {
 			/** @var DatabaseBase $conn */
 			foreach ( $conns2[$masterIndex] as $conn ) {
 				if ( $conn->trxLevel() && $conn->writesOrCallbacksPending() ) {
-					$conn->rollback( __METHOD__, 'flush' );
+					try {
+						$conn->rollback( __METHOD__, 'flush' );
+					} catch ( DBError $e ) {
+						MWExceptionHandler::logException( $e );
+						$failedServers[] = $conn->getServer();
+					}
 				}
 			}
 		}
+
+		if ( $failedServers ) {
+			throw new DBExpectedError( null, "Rollback failed on server(s) " .
+				implode( ', ', array_unique( $failedServers ) ) );
+		}
 	}
 
 	/**
 	 * @return bool Whether a master connection is already open
 	 * @since 1.24
 	 */
-	function hasMasterConnection() {
+	public function hasMasterConnection() {
 		return $this->isOpen( $this->getWriterIndex() );
 	}
 
 	/**
-	 * Determine if there are any pending changes that need to be rolled back
-	 * or committed.
+	 * Determine if there are pending changes in a transaction by this thread
 	 * @since 1.23
 	 * @return bool
 	 */
-	function hasMasterChanges() {
-		// Always 0, but who knows.. :)
+	public function hasMasterChanges() {
 		$masterIndex = $this->getWriterIndex();
 		foreach ( $this->mConns as $conns2 ) {
 			if ( empty( $conns2[$masterIndex] ) ) {
@@ -1007,17 +1053,52 @@ class LoadBalancer {
 	}
 
 	/**
+	 * Get the timestamp of the latest write query done by this thread
+	 * @since 1.25
+	 * @return float|bool UNIX timestamp or false
+	 */
+	public function lastMasterChangeTimestamp() {
+		$lastTime = false;
+		$masterIndex = $this->getWriterIndex();
+		foreach ( $this->mConns as $conns2 ) {
+			if ( empty( $conns2[$masterIndex] ) ) {
+				continue;
+			}
+			/** @var DatabaseBase $conn */
+			foreach ( $conns2[$masterIndex] as $conn ) {
+				$lastTime = max( $lastTime, $conn->lastDoneWrites() );
+			}
+		}
+		return $lastTime;
+	}
+
+	/**
+	 * Check if this load balancer object had any recent or still
+	 * pending writes issued against it by this PHP thread
+	 *
+	 * @param float $age How many seconds ago is "recent" [defaults to mWaitTimeout]
+	 * @return bool
+	 * @since 1.25
+	 */
+	public function hasOrMadeRecentMasterChanges( $age = null ) {
+		$age = ( $age === null ) ? $this->mWaitTimeout : $age;
+
+		return ( $this->hasMasterChanges()
+			|| $this->lastMasterChangeTimestamp() > microtime( true ) - $age );
+	}
+
+	/**
 	 * @param mixed $value
 	 * @return mixed
 	 */
-	function waitTimeout( $value = null ) {
+	public function waitTimeout( $value = null ) {
 		return wfSetVar( $this->mWaitTimeout, $value );
 	}
 
 	/**
 	 * @return bool
 	 */
-	function getLaggedSlaveMode() {
+	public function getLaggedSlaveMode() {
 		return $this->mLaggedSlaveMode;
 	}
 
@@ -1026,7 +1107,7 @@ class LoadBalancer {
 	 * @param null|bool $mode
 	 * @return bool
 	 */
-	function allowLagged( $mode = null ) {
+	public function allowLagged( $mode = null ) {
 		if ( $mode === null ) {
 			return $this->mAllowLagged;
 		}
@@ -1038,7 +1119,7 @@ class LoadBalancer {
 	/**
 	 * @return bool
 	 */
-	function pingAll() {
+	public function pingAll() {
 		$success = true;
 		foreach ( $this->mConns as $conns2 ) {
 			foreach ( $conns2 as $conns3 ) {
@@ -1059,7 +1140,7 @@ class LoadBalancer {
 	 * @param callable $callback
 	 * @param array $params
 	 */
-	function forEachOpenConnection( $callback, $params = array() ) {
+	public function forEachOpenConnection( $callback, array $params = array() ) {
 		foreach ( $this->mConns as $conns2 ) {
 			foreach ( $conns2 as $conns3 ) {
 				foreach ( $conns3 as $conn ) {
@@ -1071,7 +1152,8 @@ class LoadBalancer {
 	}
 
 	/**
-	 * Get the hostname and lag time of the most-lagged slave.
+	 * Get the hostname and lag time of the most-lagged slave
+	 *
 	 * This is useful for maintenance scripts that need to throttle their updates.
 	 * May attempt to open connections to slaves on the default DB. If there is
 	 * no lag, the maximum lag will be reported as -1.
@@ -1079,72 +1161,50 @@ class LoadBalancer {
 	 * @param bool|string $wiki Wiki ID, or false for the default database
 	 * @return array ( host, max lag, index of max lagged host )
 	 */
-	function getMaxLag( $wiki = false ) {
+	public function getMaxLag( $wiki = false ) {
 		$maxLag = -1;
 		$host = '';
 		$maxIndex = 0;
 
-		if ( $this->getServerCount() <= 1 ) { // no replication = no lag
-			return array( $host, $maxLag, $maxIndex );
+		if ( $this->getServerCount() <= 1 ) {
+			return array( $host, $maxLag, $maxIndex ); // no replication = no lag
 		}
 
-		// Try to get the max lag info from the server cache
-		$key = 'loadbalancer:maxlag:cluster:' . $this->mServers[0]['host'];
-		$cache = ObjectCache::newAccelerator( array(), 'hash' );
-		$maxLagInfo = $cache->get( $key ); // (host, lag, index)
-
-		// Fallback to connecting to each slave and getting the lag
-		if ( !$maxLagInfo ) {
-			foreach ( $this->mServers as $i => $conn ) {
-				if ( $i == $this->getWriterIndex() ) {
-					continue; // nothing to check
-				}
-				$conn = false;
-				if ( $wiki === false ) {
-					$conn = $this->getAnyOpenConnection( $i );
-				}
-				if ( !$conn ) {
-					$conn = $this->openConnection( $i, $wiki );
-				}
-				if ( !$conn ) {
-					continue;
-				}
-				$lag = $conn->getLag();
-				if ( $lag > $maxLag ) {
-					$maxLag = $lag;
-					$host = $this->mServers[$i]['host'];
-					$maxIndex = $i;
-				}
+		$lagTimes = $this->getLagTimes( $wiki );
+		foreach ( $lagTimes as $i => $lag ) {
+			if ( $lag > $maxLag ) {
+				$maxLag = $lag;
+				$host = $this->mServers[$i]['host'];
+				$maxIndex = $i;
 			}
-			$maxLagInfo = array( $host, $maxLag, $maxIndex );
-			$cache->set( $key, $maxLagInfo, 5 );
 		}
 
-		return $maxLagInfo;
+		return array( $host, $maxLag, $maxIndex );
 	}
 
 	/**
 	 * Get lag time for each server
-	 * Results are cached for a short time in memcached, and indefinitely in the process cache
+	 *
+	 * Results are cached for a short time in memcached/process cache
 	 *
 	 * @param string|bool $wiki
-	 * @return array
+	 * @return int[] Map of (server index => seconds)
 	 */
-	function getLagTimes( $wiki = false ) {
-		# Try process cache
-		if ( isset( $this->mLagTimes ) ) {
-			return $this->mLagTimes;
+	public function getLagTimes( $wiki = false ) {
+		if ( $this->getServerCount() <= 1 ) {
+			return array( 0 => 0 ); // no replication = no lag
 		}
-		if ( $this->getServerCount() == 1 ) {
-			# No replication
-			$this->mLagTimes = array( 0 => 0 );
-		} else {
-			# Send the request to the load monitor
-			$this->mLagTimes = $this->getLoadMonitor()->getLagTimes(
-				array_keys( $this->mServers ), $wiki );
+
+		if ( $this->mProcCache->has( 'slave_lag', 'times', 1 ) ) {
+			return $this->mProcCache->get( 'slave_lag', 'times' );
 		}
 
-		return $this->mLagTimes;
+		# Send the request to the load monitor
+		$times = $this->getLoadMonitor()->getLagTimes( array_keys( $this->mServers ), $wiki );
+
+		$this->mProcCache->set( 'slave_lag', 'times', $times );
+
+		return $times;
 	}
 
 	/**
@@ -1161,7 +1221,7 @@ class LoadBalancer {
 	 * @param DatabaseBase $conn
 	 * @return int
 	 */
-	function safeGetLag( $conn ) {
+	public function safeGetLag( $conn ) {
 		if ( $this->getServerCount() == 1 ) {
 			return 0;
 		} else {
@@ -1170,15 +1230,15 @@ class LoadBalancer {
 	}
 
 	/**
-	 * Clear the cache for getLagTimes
+	 * Clear the cache for slag lag delay times
 	 */
-	function clearLagTimeCache() {
-		$this->mLagTimes = null;
+	public function clearLagTimeCache() {
+		$this->mProcCache->clear( 'slave_lag' );
 	}
 }
 
 /**
- * Helper class to handle automatically marking connectons as reusable (via RAII pattern)
+ * Helper class to handle automatically marking connections as reusable (via RAII pattern)
  * as well handling deferring the actual network connection until the handle is used
  *
  * @ingroup Database
@@ -1186,13 +1246,13 @@ class LoadBalancer {
  */
 class DBConnRef implements IDatabase {
 	/** @var LoadBalancer */
-	protected $lb;
+	private $lb;
 
 	/** @var DatabaseBase|null */
-	protected $conn;
+	private $conn;
 
 	/** @var array|null */
-	protected $params;
+	private $params;
 
 	/**
 	 * @param LoadBalancer $lb
@@ -1216,7 +1276,7 @@ class DBConnRef implements IDatabase {
 		return call_user_func_array( array( $this->conn, $name ), $arguments );
 	}
 
-	function __destruct() {
+	public function __destruct() {
 		if ( $this->conn !== null ) {
 			$this->lb->reuseConnection( $this->conn );
 		}
diff --git a/includes/db/LoadMonitor.php b/includes/db/LoadMonitor.php
index 7281485b..91840dd9 100644
--- a/includes/db/LoadMonitor.php
+++ b/includes/db/LoadMonitor.php
@@ -48,7 +48,7 @@ interface LoadMonitor {
 	 * @param array $serverIndexes
 	 * @param string $wiki
 	 *
-	 * @return array
+	 * @return array Map of (server index => seconds)
 	 */
 	public function getLagTimes( $serverIndexes, $wiki );
 }
@@ -93,8 +93,6 @@ class LoadMonitorMySQL implements LoadMonitor {
 			return array( 0 => 0 );
 		}
 
-		$section = new ProfileSection( __METHOD__ );
-
 		$expiry = 5;
 		$requestRate = 10;
 
diff --git a/includes/db/ORMTable.php b/includes/db/ORMTable.php
index 2f898b75..562a8106 100644
--- a/includes/db/ORMTable.php
+++ b/includes/db/ORMTable.php
@@ -129,6 +129,7 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	 * Gets the db field prefix.
 	 *
 	 * @since 1.20
+	 * @deprecated since 1.25, use the $this->fieldPrefix property instead
 	 *
 	 * @return string
 	 */
@@ -189,7 +190,7 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	}
 
 	/**
-	 * Selects the the specified fields of the records matching the provided
+	 * Selects the specified fields of the records matching the provided
 	 * conditions and returns them as DBDataObject. Field names get prefixed.
 	 *
 	 * @since 1.20
@@ -210,7 +211,7 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	}
 
 	/**
-	 * Selects the the specified fields of the records matching the provided
+	 * Selects the specified fields of the records matching the provided
 	 * conditions and returns them as DBDataObject. Field names get prefixed.
 	 *
 	 * @since 1.20
@@ -247,8 +248,8 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	 * @param array $options
 	 * @param null|string $functionName
 	 * @return ResultWrapper
-	 * @throws DBQueryError If the query failed (even if the database was in
-	 *   ignoreErrors mode).
+	 * @throws Exception
+	 * @throws MWException
 	 */
 	public function rawSelect( $fields = null, array $conditions = array(),
 		array $options = array(), $functionName = null
@@ -295,7 +296,7 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	}
 
 	/**
-	 * Selects the the specified fields of the records matching the provided
+	 * Selects the specified fields of the records matching the provided
 	 * conditions and returns them as associative arrays.
 	 * Provided field names get prefixed.
 	 * Returned field names will not have a prefix.
@@ -345,7 +346,7 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	}
 
 	/**
-	 * Selects the the specified fields of the first matching record.
+	 * Selects the specified fields of the first matching record.
 	 * Field names get prefixed.
 	 *
 	 * @since 1.20
@@ -368,7 +369,7 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	}
 
 	/**
-	 * Selects the the specified fields of the records matching the provided
+	 * Selects the specified fields of the records matching the provided
 	 * conditions. Field names do NOT get prefixed.
 	 *
 	 * @since 1.20
@@ -399,7 +400,7 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	}
 
 	/**
-	 * Selects the the specified fields of the first record matching the provided
+	 * Selects the specified fields of the first record matching the provided
 	 * conditions and returns it as an associative array, or false when nothing matches.
 	 * This method makes use of selectFields and expects the same parameters and
 	 * returns the same results (if there are any, if there are none, this method returns false).
@@ -770,33 +771,54 @@ class ORMTable extends DBAccessBase implements IORMTable {
 	 * @return string
 	 */
 	public function getPrefixedField( $field ) {
-		return $this->getFieldPrefix() . $field;
+		return $this->fieldPrefix . $field;
 	}
 
 	/**
 	 * Takes an array of field names with prefix and returns the unprefixed equivalent.
 	 *
 	 * @since 1.20
+	 * @deprecated since 1.25, will be removed
 	 *
-	 * @param array $fieldNames
+	 * @param string[] $fieldNames
 	 *
-	 * @return array
+	 * @return string[]
 	 */
 	public function unprefixFieldNames( array $fieldNames ) {
-		return array_map( array( $this, 'unprefixFieldName' ), $fieldNames );
+		wfDeprecated( __METHOD__, '1.25' );
+
+		return $this->stripFieldPrefix( $fieldNames );
+	}
+
+	/**
+	 * Takes an array of field names with prefix and returns the unprefixed equivalent.
+	 *
+	 * @param string[] $fieldNames
+	 *
+	 * @return string[]
+	 */
+	private function stripFieldPrefix( array $fieldNames ) {
+		$start = strlen( $this->fieldPrefix );
+
+		return array_map( function ( $fieldName ) use ( $start ) {
+			return substr( $fieldName, $start );
+		}, $fieldNames );
 	}
 
 	/**
 	 * Takes a field name with prefix and returns the unprefixed equivalent.
 	 *
 	 * @since 1.20
+	 * @deprecated since 1.25, will be removed
 	 *
 	 * @param string $fieldName
 	 *
 	 * @return string
 	 */
 	public function unprefixFieldName( $fieldName ) {
-		return substr( $fieldName, strlen( $this->getFieldPrefix() ) );
+		wfDeprecated( __METHOD__, '1.25' );
+
+		return substr( $fieldName, strlen( $this->fieldPrefix ) );
 	}
 
 	/**
@@ -832,7 +854,7 @@ class ORMTable extends DBAccessBase implements IORMTable {
 		$result = (array)$result;
 
 		$rawFields = array_combine(
-			$this->unprefixFieldNames( array_keys( $result ) ),
+			$this->stripFieldPrefix( array_keys( $result ) ),
 			array_values( $result )
 		);