includes/libs/rdbms/database/position/MySQLMasterPos.php

   1 <?php
   2
   3 namespace Wikimedia\Rdbms;
   4
   5 use InvalidArgumentException;
   6
   7 /**
   8  * DBMasterPos class for MySQL/MariaDB
   9  *
  10  * Note that master positions and sync logic here make some assumptions:
  11  *  - Binlog-based usage assumes single-source replication and non-hierarchical replication.
  12  *  - GTID-based usage allows getting/syncing with multi-source replication. It is assumed
  13  *    that GTID sets are complete (e.g. include all domains on the server).
  14  */
  15 class MySQLMasterPos implements DBMasterPos {
  16         /** @var string Binlog file */
  17         public $file;
  18         /** @var int Binglog file position */
  19         public $pos;
  20         /** @var string[] GTID list */
  21         public $gtids = [];
  22         /** @var float UNIX timestamp */
  23         public $asOfTime = 0.0;
  24
  25         /**
  26          * @param string $file Binlog file name
  27          * @param integer $pos Binlog position
  28          * @param string $gtid Comma separated GTID set [optional]
  29          */
  30         function __construct( $file, $pos, $gtid = '' ) {
  31                 $this->file = $file;
  32                 $this->pos = $pos;
  33                 $this->gtids = array_map( 'trim', explode( ',', $gtid ) );
  34                 $this->asOfTime = microtime( true );
  35         }
  36
  37         /**
  38          * @return string <binlog file>/<position>, e.g db1034-bin.000976/843431247
  39          */
  40         function __toString() {
  41                 return "{$this->file}/{$this->pos}";
  42         }
  43
  44         function asOfTime() {
  45                 return $this->asOfTime;
  46         }
  47
  48         function hasReached( DBMasterPos $pos ) {
  49                 if ( !( $pos instanceof self ) ) {
  50                         throw new InvalidArgumentException( "Position not an instance of " . __CLASS__ );
  51                 }
  52
  53                 // Prefer GTID comparisons, which work with multi-tier replication
  54                 $thisPosByDomain = $this->getGtidCoordinates();
  55                 $thatPosByDomain = $pos->getGtidCoordinates();
  56                 if ( $thisPosByDomain && $thatPosByDomain ) {
  57                         $reached = true;
  58                         // Check that this has positions GTE all of those in $pos for all domains in $pos
  59                         foreach ( $thatPosByDomain as $domain => $thatPos ) {
  60                                 $thisPos = isset( $thisPosByDomain[$domain] ) ? $thisPosByDomain[$domain] : -1;
  61                                 $reached = $reached && ( $thatPos <= $thisPos );
  62                         }
  63
  64                         return $reached;
  65                 }
  66
  67                 // Fallback to the binlog file comparisons
  68                 $thisBinPos = $this->getBinlogCoordinates();
  69                 $thatBinPos = $pos->getBinlogCoordinates();
  70                 if ( $thisBinPos && $thatBinPos && $thisBinPos['binlog'] === $thatBinPos['binlog'] ) {
  71                         return ( $thisBinPos['pos'] >= $thatBinPos['pos'] );
  72                 }
  73
  74                 // Comparing totally different binlogs does not make sense
  75                 return false;
  76         }
  77
  78         function channelsMatch( DBMasterPos $pos ) {
  79                 if ( !( $pos instanceof self ) ) {
  80                         throw new InvalidArgumentException( "Position not an instance of " . __CLASS__ );
  81                 }
  82
  83                 // Prefer GTID comparisons, which work with multi-tier replication
  84                 $thisPosDomains = array_keys( $this->getGtidCoordinates() );
  85                 $thatPosDomains = array_keys( $pos->getGtidCoordinates() );
  86                 if ( $thisPosDomains && $thatPosDomains ) {
  87                         // Check that this has GTIDs for all domains in $pos
  88                         return !array_diff( $thatPosDomains, $thisPosDomains );
  89                 }
  90
  91                 // Fallback to the binlog file comparisons
  92                 $thisBinPos = $this->getBinlogCoordinates();
  93                 $thatBinPos = $pos->getBinlogCoordinates();
  94
  95                 return ( $thisBinPos && $thatBinPos && $thisBinPos['binlog'] === $thatBinPos['binlog'] );
  96         }
  97
  98         /**
  99          * @note: this returns false for multi-source replication GTID sets
 100          * @see https://mariadb.com/kb/en/mariadb/gtid
 101          * @see https://dev.mysql.com/doc/refman/5.6/en/replication-gtids-concepts.html
 102          * @return array Map of (domain => integer position) or false
 103          */
 104         protected function getGtidCoordinates() {
 105                 $gtidInfos = [];
 106                 foreach ( $this->gtids as $gtid ) {
 107                         $m = [];
 108                         // MariaDB style: <domain>-<server id>-<sequence number>
 109                         if ( preg_match( '!^(\d+)-\d+-(\d+)$!', $gtid, $m ) ) {
 110                                 $gtidInfos[(int)$m[1]] = (int)$m[2];
 111                                 // MySQL style: <UUID domain>:<sequence number>
 112                         } elseif ( preg_match( '!^(\w{8}-\w{4}-\w{4}-\w{4}-\w{12}):(\d+)$!', $gtid, $m ) ) {
 113                                 $gtidInfos[$m[1]] = (int)$m[2];
 114                         } else {
 115                                 $gtidInfos = [];
 116                                 break; // unrecognized GTID
 117                         }
 118
 119                 }
 120
 121                 return $gtidInfos;
 122         }
 123
 124         /**
 125          * @see https://dev.mysql.com/doc/refman/5.7/en/show-master-status.html
 126          * @see https://dev.mysql.com/doc/refman/5.7/en/show-slave-status.html
 127          * @return array|bool (binlog, (integer file number, integer position)) or false
 128          */
 129         protected function getBinlogCoordinates() {
 130                 $m = [];
 131                 if ( preg_match( '!^(.+)\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
 132                         return [ 'binlog' => $m[1], 'pos' => [ (int)$m[2], (int)$m[3] ] ];
 133                 }
 134
 135                 return false;
 136         }
 137 }