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ReplicationReporter.php

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1<?php

20namespaceWikimedia\Rdbms\Replication;

22use Psr\Log\LoggerInterface;

23useWikimedia\ObjectCache\BagOStuff;

24useWikimedia\Rdbms\DBError;

25useWikimedia\Rdbms\DBPrimaryPos;

26useWikimedia\Rdbms\IDatabase;

33classReplicationReporter {

35protected$topologyRole;

37protected$logger;

39protected$srvCache;

41private $trxReplicaLagStatus =null;

48publicfunction__construct($topologyRole,$logger,$srvCache ) {

49 $this->topologyRole =$topologyRole;

50 $this->logger =$logger;

51 $this->srvCache =$srvCache;

52 }

57publicfunctiongetTopologyRole() {

58return$this->topologyRole;

59 }

64publicfunctiongetLag(IDatabase $conn ) {

65if ( $this->topologyRole ===IDatabase::ROLE_STREAMING_MASTER ) {

66return 0;// this is the primary DB

67 } elseif ( $this->topologyRole ===IDatabase::ROLE_STATIC_CLONE ) {

68return 0;// static dataset

69 }

71return $this->doGetLag( $conn );

72 }

85protectedfunctiondoGetLag(IDatabase $conn ) {

86return 0;

87 }

98protectedfunctiongetApproximateLagStatus(IDatabase $conn ) {

99if ( $this->topologyRole ===IDatabase::ROLE_STREAMING_REPLICA ) {

100// Avoid exceptions as this is used internally in critical sections

101try {

102 $lag = $this->getLag( $conn );

103 }catch (DBError ) {

104 $lag =false;

105 }

106 }else {

107 $lag = 0;

108 }

109

110return ['lag' => $lag,'since' => microtime(true ) ];

111 }

112

119publicfunctionprimaryPosWait(IDatabase $conn,DBPrimaryPos $pos, $timeout ) {

120// Real waits are implemented in the subclass.

121return 0;

122 }

123

127publicfunctiongetReplicaPos(IDatabase $conn ) {

128// Stub

129returnfalse;

130 }

131

135publicfunctiongetPrimaryPos(IDatabase $conn ) {

136// Stub

137returnfalse;

138 }

139

143publicfunctiongetTopologyBasedReadOnlyReason() {

144if ( $this->topologyRole ===IDatabase::ROLE_STREAMING_REPLICA ) {

145return ['Server is configured as a read-only replica database.','role' ];

146 } elseif ( $this->topologyRole ===IDatabase::ROLE_STATIC_CLONE ) {

147return ['Server is configured as a read-only static clone database.','role' ];

148 }

149

150returnnull;

151 }

152

153publicfunctionresetReplicationLagStatus(IDatabase $conn ) {

154// With REPEATABLE-READ isolation, the first SELECT establishes the read snapshot,

155// so get the replication lag estimate before any transaction SELECT queries come in.

156// This way, the lag estimate reflects what will actually be read. Also, if heartbeat

157// tables are used, this avoids counting snapshot lag as part of replication lag.

158 $this->trxReplicaLagStatus =null;// clear cached value first

159 $this->trxReplicaLagStatus = $this->getApproximateLagStatus( $conn );

160 }

161

177finalprotectedfunctiongetRecordedTransactionLagStatus(IDatabase $conn ) {

178return $conn->trxLevel() ? $this->trxReplicaLagStatus :null;

179 }

180

184publicfunctiongetSessionLagStatus(IDatabase $conn ) {

185return $this->getRecordedTransactionLagStatus( $conn ) ?: $this->getApproximateLagStatus( $conn );

186 }

187

195protectedfunctiongetLogContext(IDatabase $conn, array $extras = [] ) {

196return array_merge(

197 [

198'db_server' => $conn->getServerName(),

199'db_name' => $conn->getDBname(),

200// TODO: Add db_user

201 ],

202 $extras

203 );

204 }

205}

Wikimedia\ObjectCache\BagOStuff

Abstract class for any ephemeral data store.

DefinitionBagOStuff.php:87

Wikimedia\Rdbms\DBError

Database error base class.

DefinitionDBError.php:36

Wikimedia\Rdbms\Replication\ReplicationReporter

DefinitionReplicationReporter.php:33

Wikimedia\Rdbms\Replication\ReplicationReporter\getSessionLagStatus

getSessionLagStatus(IDatabase $conn)

DefinitionReplicationReporter.php:184

Wikimedia\Rdbms\Replication\ReplicationReporter\$srvCache

BagOStuff $srvCache

DefinitionReplicationReporter.php:39

Wikimedia\Rdbms\Replication\ReplicationReporter\$logger

LoggerInterface $logger

DefinitionReplicationReporter.php:37

Wikimedia\Rdbms\Replication\ReplicationReporter\primaryPosWait

primaryPosWait(IDatabase $conn, DBPrimaryPos $pos, $timeout)

DefinitionReplicationReporter.php:119

Wikimedia\Rdbms\Replication\ReplicationReporter\getPrimaryPos

getPrimaryPos(IDatabase $conn)

DefinitionReplicationReporter.php:135

Wikimedia\Rdbms\Replication\ReplicationReporter\getTopologyBasedReadOnlyReason

getTopologyBasedReadOnlyReason()

DefinitionReplicationReporter.php:143

Wikimedia\Rdbms\Replication\ReplicationReporter\getLogContext

getLogContext(IDatabase $conn, array $extras=[])

Create a log context to pass to PSR-3 logger functions.

DefinitionReplicationReporter.php:195

Wikimedia\Rdbms\Replication\ReplicationReporter\__construct

__construct( $topologyRole, $logger, $srvCache)

DefinitionReplicationReporter.php:48

Wikimedia\Rdbms\Replication\ReplicationReporter\resetReplicationLagStatus

resetReplicationLagStatus(IDatabase $conn)

DefinitionReplicationReporter.php:153

Wikimedia\Rdbms\Replication\ReplicationReporter\doGetLag

doGetLag(IDatabase $conn)

Get the amount of replication lag for this database server.

DefinitionReplicationReporter.php:85

Wikimedia\Rdbms\Replication\ReplicationReporter\getReplicaPos

getReplicaPos(IDatabase $conn)

DefinitionReplicationReporter.php:127

Wikimedia\Rdbms\Replication\ReplicationReporter\getApproximateLagStatus

getApproximateLagStatus(IDatabase $conn)

Get a replica DB lag estimate for this server at the start of a transaction.

DefinitionReplicationReporter.php:98

Wikimedia\Rdbms\Replication\ReplicationReporter\$topologyRole

string $topologyRole

Replication topology role of the server; one of the class ROLE_* constants.

DefinitionReplicationReporter.php:35

Wikimedia\Rdbms\Replication\ReplicationReporter\getTopologyRole

getTopologyRole()

DefinitionReplicationReporter.php:57

Wikimedia\Rdbms\Replication\ReplicationReporter\getRecordedTransactionLagStatus

getRecordedTransactionLagStatus(IDatabase $conn)

Get the replica DB lag when the current transaction started.

DefinitionReplicationReporter.php:177

Wikimedia\Rdbms\Replication\ReplicationReporter\getLag

getLag(IDatabase $conn)

DefinitionReplicationReporter.php:64

Wikimedia\Rdbms\DBPrimaryPos

An object representing a primary or replica DB position in a replicated setup.

DefinitionDBPrimaryPos.php:14

Wikimedia\Rdbms\IDatabase

Interface to a relational database.

DefinitionIDatabase.php:45

Wikimedia\Rdbms\IDatabase\ROLE_STREAMING_MASTER

const ROLE_STREAMING_MASTER

Primary server than can stream writes to replica servers.

DefinitionIDatabase.php:108

Wikimedia\Rdbms\IDatabase\ROLE_STATIC_CLONE

const ROLE_STATIC_CLONE

Replica server within a static dataset.

DefinitionIDatabase.php:112

Wikimedia\Rdbms\IDatabase\ROLE_STREAMING_REPLICA

const ROLE_STREAMING_REPLICA

Replica server that receives writes from a primary server.

DefinitionIDatabase.php:110

Wikimedia\Rdbms\IDatabase\trxLevel

trxLevel()

Gets the current transaction level.

Wikimedia\Rdbms\IReadableDatabase\getDBname

getDBname()

Get the current database name; null if there isn't one.

Wikimedia\Rdbms\IReadableDatabase\getServerName

getServerName()

Get the readable name for the server.

Wikimedia\Rdbms\Replication

DefinitionMysqlReplicationReporter.php:20