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diff --git a/www/wiki/includes/libs/rdbms/connectionmanager/SessionConsistentConnectionManager.php b/www/wiki/includes/libs/rdbms/connectionmanager/SessionConsistentConnectionManager.php
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+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Database
+ */
+
+namespace Wikimedia\Rdbms;
+
+/**
+ * Database connection manager.
+ *
+ * This manages access to master and replica databases. It also manages state that indicates whether
+ * the replica databases are possibly outdated after a write operation, and thus the master database
+ * should be used for subsequent read operations.
+ *
+ * @note: Services that access overlapping sets of database tables, or interact with logically
+ * related sets of data in the database, should share a SessionConsistentConnectionManager.
+ * Services accessing unrelated sets of information may prefer to not share a
+ * SessionConsistentConnectionManager, so they can still perform read operations against replica
+ * databases after a (unrelated, per the assumption) write operation to the master database.
+ * Generally, sharing a SessionConsistentConnectionManager improves consistency (by avoiding race
+ * conditions due to replication lag), but can reduce performance (by directing more read
+ * operations to the master database server).
+ *
+ * @since 1.29
+ *
+ * @author Daniel Kinzler
+ * @author Addshore
+ */
+class SessionConsistentConnectionManager extends ConnectionManager {
+
+	/**
+	 * @var bool
+	 */
+	private $forceWriteConnection = false;
+
+	/**
+	 * Forces all future calls to getReadConnection() to return a write connection.
+	 * Use this before performing read operations that are critical for a future update.
+	 *
+	 * @since 1.29
+	 */
+	public function prepareForUpdates() {
+		$this->forceWriteConnection = true;
+	}
+
+	/**
+	 * @since 1.29
+	 *
+	 * @param string[]|null $groups
+	 *
+	 * @return Database
+	 */
+	public function getReadConnection( array $groups = null ) {
+		if ( $this->forceWriteConnection ) {
+			return parent::getWriteConnection();
+		}
+
+		return parent::getReadConnection( $groups );
+	}
+
+	/**
+	 * @since 1.29
+	 *
+	 * @return Database
+	 */
+	public function getWriteConnection() {
+		$this->prepareForUpdates();
+		return parent::getWriteConnection();
+	}
+
+	/**
+	 * @since 1.29
+	 *
+	 * @param string[]|null $groups
+	 *
+	 * @return DBConnRef
+	 */
+	public function getReadConnectionRef( array $groups = null ) {
+		if ( $this->forceWriteConnection ) {
+			return parent::getWriteConnectionRef();
+		}
+
+		return parent::getReadConnectionRef( $groups );
+	}
+
+	/**
+	 * @since 1.29
+	 *
+	 * @return DBConnRef
+	 */
+	public function getWriteConnectionRef() {
+		$this->prepareForUpdates();
+		return parent::getWriteConnectionRef();
+	}
+
+}