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[autoinstallsdev/mediawiki.git] / 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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+<?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;
+       }
+}