X-Git-Url: https://scripts.mit.edu/gitweb/autoinstallsdev/mediawiki.git/blobdiff_plain/19e297c21b10b1b8a3acad5e73fc71dcb35db44a..6932310fd58ebef145fa01eb76edf7150284d8ea:/includes/libs/rdbms/database/position/MySQLMasterPos.php

diff --git a/includes/libs/rdbms/database/position/MySQLMasterPos.php b/includes/libs/rdbms/database/position/MySQLMasterPos.php
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+++ b/includes/libs/rdbms/database/position/MySQLMasterPos.php
@@ -0,0 +1,137 @@
+<?php
+
+namespace Wikimedia\Rdbms;
+
+use InvalidArgumentException;
+
+/**
+ * DBMasterPos class for MySQL/MariaDB
+ *
+ * Note that master positions and sync logic here make some assumptions:
+ *  - Binlog-based usage assumes single-source replication and non-hierarchical replication.
+ *  - GTID-based usage allows getting/syncing with multi-source replication. It is assumed
+ *    that GTID sets are complete (e.g. include all domains on the server).
+ */
+class MySQLMasterPos implements DBMasterPos {
+	/** @var string Binlog file */
+	public $file;
+	/** @var int Binglog file position */
+	public $pos;
+	/** @var string[] GTID list */
+	public $gtids = [];
+	/** @var float UNIX timestamp */
+	public $asOfTime = 0.0;
+
+	/**
+	 * @param string $file Binlog file name
+	 * @param int $pos Binlog position
+	 * @param string $gtid Comma separated GTID set [optional]
+	 */
+	function __construct( $file, $pos, $gtid = '' ) {
+		$this->file = $file;
+		$this->pos = $pos;
+		$this->gtids = array_map( 'trim', explode( ',', $gtid ) );
+		$this->asOfTime = microtime( true );
+	}
+
+	/**
+	 * @return string <binlog file>/<position>, e.g db1034-bin.000976/843431247
+	 */
+	function __toString() {
+		return "{$this->file}/{$this->pos}";
+	}
+
+	function asOfTime() {
+		return $this->asOfTime;
+	}
+
+	function hasReached( DBMasterPos $pos ) {
+		if ( !( $pos instanceof self ) ) {
+			throw new InvalidArgumentException( "Position not an instance of " . __CLASS__ );
+		}
+
+		// Prefer GTID comparisons, which work with multi-tier replication
+		$thisPosByDomain = $this->getGtidCoordinates();
+		$thatPosByDomain = $pos->getGtidCoordinates();
+		if ( $thisPosByDomain && $thatPosByDomain ) {
+			$reached = true;
+			// Check that this has positions GTE all of those in $pos for all domains in $pos
+			foreach ( $thatPosByDomain as $domain => $thatPos ) {
+				$thisPos = isset( $thisPosByDomain[$domain] ) ? $thisPosByDomain[$domain] : -1;
+				$reached = $reached && ( $thatPos <= $thisPos );
+			}
+
+			return $reached;
+		}
+
+		// Fallback to the binlog file comparisons
+		$thisBinPos = $this->getBinlogCoordinates();
+		$thatBinPos = $pos->getBinlogCoordinates();
+		if ( $thisBinPos && $thatBinPos && $thisBinPos['binlog'] === $thatBinPos['binlog'] ) {
+			return ( $thisBinPos['pos'] >= $thatBinPos['pos'] );
+		}
+
+		// Comparing totally different binlogs does not make sense
+		return false;
+	}
+
+	function channelsMatch( DBMasterPos $pos ) {
+		if ( !( $pos instanceof self ) ) {
+			throw new InvalidArgumentException( "Position not an instance of " . __CLASS__ );
+		}
+
+		// Prefer GTID comparisons, which work with multi-tier replication
+		$thisPosDomains = array_keys( $this->getGtidCoordinates() );
+		$thatPosDomains = array_keys( $pos->getGtidCoordinates() );
+		if ( $thisPosDomains && $thatPosDomains ) {
+			// Check that this has GTIDs for all domains in $pos
+			return !array_diff( $thatPosDomains, $thisPosDomains );
+		}
+
+		// Fallback to the binlog file comparisons
+		$thisBinPos = $this->getBinlogCoordinates();
+		$thatBinPos = $pos->getBinlogCoordinates();
+
+		return ( $thisBinPos && $thatBinPos && $thisBinPos['binlog'] === $thatBinPos['binlog'] );
+	}
+
+	/**
+	 * @note: this returns false for multi-source replication GTID sets
+	 * @see https://mariadb.com/kb/en/mariadb/gtid
+	 * @see https://dev.mysql.com/doc/refman/5.6/en/replication-gtids-concepts.html
+	 * @return array Map of (domain => integer position) or false
+	 */
+	protected function getGtidCoordinates() {
+		$gtidInfos = [];
+		foreach ( $this->gtids as $gtid ) {
+			$m = [];
+			// MariaDB style: <domain>-<server id>-<sequence number>
+			if ( preg_match( '!^(\d+)-\d+-(\d+)$!', $gtid, $m ) ) {
+				$gtidInfos[(int)$m[1]] = (int)$m[2];
+				// MySQL style: <UUID domain>:<sequence number>
+			} elseif ( preg_match( '!^(\w{8}-\w{4}-\w{4}-\w{4}-\w{12}):(\d+)$!', $gtid, $m ) ) {
+				$gtidInfos[$m[1]] = (int)$m[2];
+			} else {
+				$gtidInfos = [];
+				break; // unrecognized GTID
+			}
+
+		}
+
+		return $gtidInfos;
+	}
+
+	/**
+	 * @see https://dev.mysql.com/doc/refman/5.7/en/show-master-status.html
+	 * @see https://dev.mysql.com/doc/refman/5.7/en/show-slave-status.html
+	 * @return array|bool (binlog, (integer file number, integer position)) or false
+	 */
+	protected function getBinlogCoordinates() {
+		$m = [];
+		if ( preg_match( '!^(.+)\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
+			return [ 'binlog' => $m[1], 'pos' => [ (int)$m[2], (int)$m[3] ] ];
+		}
+
+		return false;
+	}
+}