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Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like LoadBalancer often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use LoadBalancer, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 30 | class LoadBalancer implements ILoadBalancer { |
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| 31 | /** @var array[] Map of (server index => server config array) */ |
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| 32 | private $mServers; |
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| 33 | /** @var array[] Map of (local/foreignUsed/foreignFree => server index => IDatabase array) */ |
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| 34 | private $mConns; |
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| 35 | /** @var float[] Map of (server index => weight) */ |
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| 36 | private $mLoads; |
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| 37 | /** @var array[] Map of (group => server index => weight) */ |
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| 38 | private $mGroupLoads; |
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| 39 | /** @var bool Whether to disregard replica DB lag as a factor in replica DB selection */ |
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| 40 | private $mAllowLagged; |
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| 41 | /** @var integer Seconds to spend waiting on replica DB lag to resolve */ |
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| 42 | private $mWaitTimeout; |
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| 43 | /** @var array The LoadMonitor configuration */ |
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| 44 | private $loadMonitorConfig; |
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| 45 | /** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */ |
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| 46 | private $tableAliases = []; |
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| 47 | |||
| 48 | /** @var ILoadMonitor */ |
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| 49 | private $loadMonitor; |
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| 50 | /** @var BagOStuff */ |
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| 51 | private $srvCache; |
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| 52 | /** @var BagOStuff */ |
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| 53 | private $memCache; |
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| 54 | /** @var WANObjectCache */ |
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| 55 | private $wanCache; |
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| 56 | /** @var object|string Class name or object With profileIn/profileOut methods */ |
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| 57 | protected $profiler; |
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| 58 | /** @var TransactionProfiler */ |
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| 59 | protected $trxProfiler; |
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| 60 | /** @var LoggerInterface */ |
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| 61 | protected $replLogger; |
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| 62 | /** @var LoggerInterface */ |
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| 63 | protected $connLogger; |
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| 64 | /** @var LoggerInterface */ |
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| 65 | protected $queryLogger; |
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| 66 | /** @var LoggerInterface */ |
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| 67 | protected $perfLogger; |
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| 68 | |||
| 69 | /** @var bool|IDatabase Database connection that caused a problem */ |
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| 70 | private $mErrorConnection; |
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| 71 | /** @var integer The generic (not query grouped) replica DB index (of $mServers) */ |
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| 72 | private $mReadIndex; |
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| 73 | /** @var bool|DBMasterPos False if not set */ |
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| 74 | private $mWaitForPos; |
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| 75 | /** @var bool Whether the generic reader fell back to a lagged replica DB */ |
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| 76 | private $laggedReplicaMode = false; |
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| 77 | /** @var bool Whether the generic reader fell back to a lagged replica DB */ |
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| 78 | private $allReplicasDownMode = false; |
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| 79 | /** @var string The last DB selection or connection error */ |
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| 80 | private $mLastError = 'Unknown error'; |
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| 81 | /** @var string|bool Reason the LB is read-only or false if not */ |
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| 82 | private $readOnlyReason = false; |
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| 83 | /** @var integer Total connections opened */ |
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| 84 | private $connsOpened = 0; |
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| 85 | /** @var string|bool String if a requested DBO_TRX transaction round is active */ |
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| 86 | private $trxRoundId = false; |
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| 87 | /** @var array[] Map of (name => callable) */ |
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| 88 | private $trxRecurringCallbacks = []; |
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| 89 | /** @var DatabaseDomain Local Domain ID and default for selectDB() calls */ |
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| 90 | private $localDomain; |
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| 91 | /** @var string Alternate ID string for the domain instead of DatabaseDomain::getId() */ |
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| 92 | private $localDomainIdAlias; |
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| 93 | /** @var string Current server name */ |
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| 94 | private $host; |
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| 95 | /** @var bool Whether this PHP instance is for a CLI script */ |
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| 96 | protected $cliMode; |
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| 97 | /** @var string Agent name for query profiling */ |
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| 98 | protected $agent; |
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| 99 | |||
| 100 | /** @var callable Exception logger */ |
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| 101 | private $errorLogger; |
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| 102 | |||
| 103 | /** @var boolean */ |
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| 104 | private $disabled = false; |
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| 105 | |||
| 106 | /** @var integer Warn when this many connection are held */ |
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| 107 | const CONN_HELD_WARN_THRESHOLD = 10; |
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| 108 | |||
| 109 | /** @var integer Default 'max lag' when unspecified */ |
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| 110 | const MAX_LAG_DEFAULT = 10; |
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| 111 | /** @var integer Seconds to cache master server read-only status */ |
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| 112 | const TTL_CACHE_READONLY = 5; |
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| 113 | |||
| 114 | public function __construct( array $params ) { |
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| 115 | if ( !isset( $params['servers'] ) ) { |
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| 116 | throw new InvalidArgumentException( __CLASS__ . ': missing servers parameter' ); |
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| 117 | } |
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| 118 | $this->mServers = $params['servers']; |
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| 119 | |||
| 120 | $this->localDomain = isset( $params['localDomain'] ) |
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| 121 | ? DatabaseDomain::newFromId( $params['localDomain'] ) |
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| 122 | : DatabaseDomain::newUnspecified(); |
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| 123 | // In case a caller assumes that the domain ID is simply <db>-<prefix>, which is almost |
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| 124 | // always true, gracefully handle the case when they fail to account for escaping. |
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| 125 | if ( $this->localDomain->getTablePrefix() != '' ) { |
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| 126 | $this->localDomainIdAlias = |
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| 127 | $this->localDomain->getDatabase() . '-' . $this->localDomain->getTablePrefix(); |
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| 128 | } else { |
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| 129 | $this->localDomainIdAlias = $this->localDomain->getDatabase(); |
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| 130 | } |
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| 131 | |||
| 132 | $this->mWaitTimeout = isset( $params['waitTimeout'] ) ? $params['waitTimeout'] : 10; |
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| 133 | |||
| 134 | $this->mReadIndex = -1; |
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| 135 | $this->mConns = [ |
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|
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| 136 | 'local' => [], |
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| 137 | 'foreignUsed' => [], |
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| 138 | 'foreignFree' => [] |
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| 139 | ]; |
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| 140 | $this->mLoads = []; |
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| 141 | $this->mWaitForPos = false; |
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| 142 | $this->mErrorConnection = false; |
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| 143 | $this->mAllowLagged = false; |
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| 144 | |||
| 145 | View Code Duplication | if ( isset( $params['readOnlyReason'] ) && is_string( $params['readOnlyReason'] ) ) { |
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| 146 | $this->readOnlyReason = $params['readOnlyReason']; |
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| 147 | } |
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| 148 | |||
| 149 | if ( isset( $params['loadMonitor'] ) ) { |
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| 150 | $this->loadMonitorConfig = $params['loadMonitor']; |
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| 151 | } else { |
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| 152 | $this->loadMonitorConfig = [ 'class' => 'LoadMonitorNull' ]; |
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| 153 | } |
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| 154 | |||
| 155 | foreach ( $params['servers'] as $i => $server ) { |
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| 156 | $this->mLoads[$i] = $server['load']; |
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| 157 | if ( isset( $server['groupLoads'] ) ) { |
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| 158 | foreach ( $server['groupLoads'] as $group => $ratio ) { |
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| 159 | if ( !isset( $this->mGroupLoads[$group] ) ) { |
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| 160 | $this->mGroupLoads[$group] = []; |
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| 161 | } |
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| 162 | $this->mGroupLoads[$group][$i] = $ratio; |
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| 163 | } |
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| 164 | } |
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| 165 | } |
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| 166 | |||
| 167 | if ( isset( $params['srvCache'] ) ) { |
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| 168 | $this->srvCache = $params['srvCache']; |
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| 169 | } else { |
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| 170 | $this->srvCache = new EmptyBagOStuff(); |
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| 171 | } |
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| 172 | if ( isset( $params['memCache'] ) ) { |
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| 173 | $this->memCache = $params['memCache']; |
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| 174 | } else { |
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| 175 | $this->memCache = new EmptyBagOStuff(); |
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| 176 | } |
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| 177 | if ( isset( $params['wanCache'] ) ) { |
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| 178 | $this->wanCache = $params['wanCache']; |
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| 179 | } else { |
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| 180 | $this->wanCache = WANObjectCache::newEmpty(); |
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| 181 | } |
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| 182 | $this->profiler = isset( $params['profiler'] ) ? $params['profiler'] : null; |
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| 183 | if ( isset( $params['trxProfiler'] ) ) { |
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| 184 | $this->trxProfiler = $params['trxProfiler']; |
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| 185 | } else { |
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| 186 | $this->trxProfiler = new TransactionProfiler(); |
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| 187 | } |
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| 188 | |||
| 189 | $this->errorLogger = isset( $params['errorLogger'] ) |
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| 190 | ? $params['errorLogger'] |
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| 191 | : function ( Exception $e ) { |
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| 192 | trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_WARNING ); |
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| 193 | }; |
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| 194 | |||
| 195 | foreach ( [ 'replLogger', 'connLogger', 'queryLogger', 'perfLogger' ] as $key ) { |
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| 196 | $this->$key = isset( $params[$key] ) ? $params[$key] : new \Psr\Log\NullLogger(); |
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| 197 | } |
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| 198 | |||
| 199 | $this->host = isset( $params['hostname'] ) |
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| 200 | ? $params['hostname'] |
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| 201 | : ( gethostname() ?: 'unknown' ); |
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| 202 | $this->cliMode = isset( $params['cliMode'] ) ? $params['cliMode'] : PHP_SAPI === 'cli'; |
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| 203 | $this->agent = isset( $params['agent'] ) ? $params['agent'] : ''; |
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| 204 | } |
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| 205 | |||
| 206 | /** |
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| 207 | * Get a LoadMonitor instance |
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| 208 | * |
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| 209 | * @return ILoadMonitor |
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| 210 | */ |
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| 211 | private function getLoadMonitor() { |
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| 212 | if ( !isset( $this->loadMonitor ) ) { |
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| 213 | $class = $this->loadMonitorConfig['class']; |
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| 214 | $this->loadMonitor = new $class( |
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| 215 | $this, $this->srvCache, $this->memCache, $this->loadMonitorConfig ); |
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| 216 | $this->loadMonitor->setLogger( $this->replLogger ); |
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| 217 | } |
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| 218 | |||
| 219 | return $this->loadMonitor; |
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| 220 | } |
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| 221 | |||
| 222 | /** |
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| 223 | * @param array $loads |
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| 224 | * @param bool|string $domain Domain to get non-lagged for |
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| 225 | * @param int $maxLag Restrict the maximum allowed lag to this many seconds |
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| 226 | * @return bool|int|string |
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| 227 | */ |
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| 228 | private function getRandomNonLagged( array $loads, $domain = false, $maxLag = INF ) { |
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| 229 | $lags = $this->getLagTimes( $domain ); |
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| 230 | |||
| 231 | # Unset excessively lagged servers |
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| 232 | foreach ( $lags as $i => $lag ) { |
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| 233 | if ( $i != 0 ) { |
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| 234 | # How much lag this server nominally is allowed to have |
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| 235 | $maxServerLag = isset( $this->mServers[$i]['max lag'] ) |
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| 236 | ? $this->mServers[$i]['max lag'] |
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| 237 | : self::MAX_LAG_DEFAULT; // default |
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| 238 | # Constrain that futher by $maxLag argument |
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| 239 | $maxServerLag = min( $maxServerLag, $maxLag ); |
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| 240 | |||
| 241 | $host = $this->getServerName( $i ); |
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| 242 | if ( $lag === false && !is_infinite( $maxServerLag ) ) { |
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| 243 | $this->replLogger->error( "Server $host (#$i) is not replicating?" ); |
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| 244 | unset( $loads[$i] ); |
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| 245 | } elseif ( $lag > $maxServerLag ) { |
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| 246 | $this->replLogger->warning( "Server $host (#$i) has >= $lag seconds of lag" ); |
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| 247 | unset( $loads[$i] ); |
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| 248 | } |
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| 249 | } |
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| 250 | } |
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| 251 | |||
| 252 | # Find out if all the replica DBs with non-zero load are lagged |
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| 253 | $sum = 0; |
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| 254 | foreach ( $loads as $load ) { |
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| 255 | $sum += $load; |
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| 256 | } |
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| 257 | if ( $sum == 0 ) { |
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| 258 | # No appropriate DB servers except maybe the master and some replica DBs with zero load |
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| 259 | # Do NOT use the master |
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| 260 | # Instead, this function will return false, triggering read-only mode, |
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| 261 | # and a lagged replica DB will be used instead. |
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| 262 | return false; |
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| 263 | } |
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| 264 | |||
| 265 | if ( count( $loads ) == 0 ) { |
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| 266 | return false; |
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| 267 | } |
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| 268 | |||
| 269 | # Return a random representative of the remainder |
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| 270 | return ArrayUtils::pickRandom( $loads ); |
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| 271 | } |
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| 272 | |||
| 273 | public function getReaderIndex( $group = false, $domain = false ) { |
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| 274 | if ( count( $this->mServers ) == 1 ) { |
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| 275 | # Skip the load balancing if there's only one server |
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| 276 | return $this->getWriterIndex(); |
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| 277 | } elseif ( $group === false && $this->mReadIndex >= 0 ) { |
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| 278 | # Shortcut if generic reader exists already |
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| 279 | return $this->mReadIndex; |
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| 280 | } |
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| 281 | |||
| 282 | # Find the relevant load array |
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| 283 | if ( $group !== false ) { |
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| 284 | if ( isset( $this->mGroupLoads[$group] ) ) { |
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| 285 | $nonErrorLoads = $this->mGroupLoads[$group]; |
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| 286 | } else { |
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| 287 | # No loads for this group, return false and the caller can use some other group |
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| 288 | $this->connLogger->info( __METHOD__ . ": no loads for group $group" ); |
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| 289 | |||
| 290 | return false; |
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| 291 | } |
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| 292 | } else { |
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| 293 | $nonErrorLoads = $this->mLoads; |
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| 294 | } |
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| 295 | |||
| 296 | if ( !count( $nonErrorLoads ) ) { |
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| 297 | throw new InvalidArgumentException( "Empty server array given to LoadBalancer" ); |
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| 298 | } |
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| 299 | |||
| 300 | # Scale the configured load ratios according to the dynamic load if supported |
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| 301 | $this->getLoadMonitor()->scaleLoads( $nonErrorLoads, $domain ); |
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| 302 | |||
| 303 | $laggedReplicaMode = false; |
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| 304 | |||
| 305 | # No server found yet |
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| 306 | $i = false; |
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| 307 | # First try quickly looking through the available servers for a server that |
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| 308 | # meets our criteria |
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| 309 | $currentLoads = $nonErrorLoads; |
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| 310 | while ( count( $currentLoads ) ) { |
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| 311 | if ( $this->mAllowLagged || $laggedReplicaMode ) { |
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| 312 | $i = ArrayUtils::pickRandom( $currentLoads ); |
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| 313 | } else { |
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| 314 | $i = false; |
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| 315 | if ( $this->mWaitForPos && $this->mWaitForPos->asOfTime() ) { |
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| 316 | # ChronologyProtecter causes mWaitForPos to be set via sessions. |
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| 317 | # This triggers doWait() after connect, so it's especially good to |
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| 318 | # avoid lagged servers so as to avoid just blocking in that method. |
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| 319 | $ago = microtime( true ) - $this->mWaitForPos->asOfTime(); |
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| 320 | # Aim for <= 1 second of waiting (being too picky can backfire) |
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| 321 | $i = $this->getRandomNonLagged( $currentLoads, $domain, $ago + 1 ); |
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| 322 | } |
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| 323 | if ( $i === false ) { |
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| 324 | # Any server with less lag than it's 'max lag' param is preferable |
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| 325 | $i = $this->getRandomNonLagged( $currentLoads, $domain ); |
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| 326 | } |
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| 327 | if ( $i === false && count( $currentLoads ) != 0 ) { |
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| 328 | # All replica DBs lagged. Switch to read-only mode |
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| 329 | $this->replLogger->error( "All replica DBs lagged. Switch to read-only mode" ); |
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| 330 | $i = ArrayUtils::pickRandom( $currentLoads ); |
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| 331 | $laggedReplicaMode = true; |
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| 332 | } |
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| 333 | } |
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| 334 | |||
| 335 | if ( $i === false ) { |
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| 336 | # pickRandom() returned false |
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| 337 | # This is permanent and means the configuration or the load monitor |
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| 338 | # wants us to return false. |
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| 339 | $this->connLogger->debug( __METHOD__ . ": pickRandom() returned false" ); |
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| 340 | |||
| 341 | return false; |
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| 342 | } |
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| 343 | |||
| 344 | $serverName = $this->getServerName( $i ); |
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| 345 | $this->connLogger->debug( __METHOD__ . ": Using reader #$i: $serverName..." ); |
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| 346 | |||
| 347 | $conn = $this->openConnection( $i, $domain ); |
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| 348 | if ( !$conn ) { |
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| 349 | $this->connLogger->warning( __METHOD__ . ": Failed connecting to $i/$domain" ); |
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| 350 | unset( $nonErrorLoads[$i] ); |
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| 351 | unset( $currentLoads[$i] ); |
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| 352 | $i = false; |
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| 353 | continue; |
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| 354 | } |
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| 355 | |||
| 356 | // Decrement reference counter, we are finished with this connection. |
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| 357 | // It will be incremented for the caller later. |
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| 358 | if ( $domain !== false ) { |
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| 359 | $this->reuseConnection( $conn ); |
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| 360 | } |
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| 361 | |||
| 362 | # Return this server |
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| 363 | break; |
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| 364 | } |
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| 365 | |||
| 366 | # If all servers were down, quit now |
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| 367 | if ( !count( $nonErrorLoads ) ) { |
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| 368 | $this->connLogger->error( "All servers down" ); |
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| 369 | } |
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| 370 | |||
| 371 | if ( $i !== false ) { |
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| 372 | # Replica DB connection successful. |
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| 373 | # Wait for the session master pos for a short time. |
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| 374 | if ( $this->mWaitForPos && $i > 0 ) { |
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| 375 | $this->doWait( $i ); |
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| 376 | } |
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| 377 | if ( $this->mReadIndex <= 0 && $this->mLoads[$i] > 0 && $group === false ) { |
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| 378 | $this->mReadIndex = $i; |
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| 379 | # Record if the generic reader index is in "lagged replica DB" mode |
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| 380 | if ( $laggedReplicaMode ) { |
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| 381 | $this->laggedReplicaMode = true; |
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| 382 | } |
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| 383 | } |
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| 384 | $serverName = $this->getServerName( $i ); |
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| 385 | $this->connLogger->debug( |
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| 386 | __METHOD__ . ": using server $serverName for group '$group'" ); |
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| 387 | } |
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| 388 | |||
| 389 | return $i; |
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| 390 | } |
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| 391 | |||
| 392 | public function waitFor( $pos ) { |
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| 393 | $this->mWaitForPos = $pos; |
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| 394 | $i = $this->mReadIndex; |
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| 395 | |||
| 396 | if ( $i > 0 ) { |
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| 397 | if ( !$this->doWait( $i ) ) { |
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| 398 | $this->laggedReplicaMode = true; |
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| 399 | } |
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| 400 | } |
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| 401 | } |
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| 402 | |||
| 403 | public function waitForOne( $pos, $timeout = null ) { |
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| 404 | $this->mWaitForPos = $pos; |
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| 405 | |||
| 406 | $i = $this->mReadIndex; |
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| 407 | if ( $i <= 0 ) { |
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| 408 | // Pick a generic replica DB if there isn't one yet |
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| 409 | $readLoads = $this->mLoads; |
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| 410 | unset( $readLoads[$this->getWriterIndex()] ); // replica DBs only |
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| 411 | $readLoads = array_filter( $readLoads ); // with non-zero load |
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| 412 | $i = ArrayUtils::pickRandom( $readLoads ); |
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| 413 | } |
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| 414 | |||
| 415 | View Code Duplication | if ( $i > 0 ) { |
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| 416 | $ok = $this->doWait( $i, true, $timeout ); |
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| 417 | } else { |
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| 418 | $ok = true; // no applicable loads |
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| 419 | } |
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| 420 | |||
| 421 | return $ok; |
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| 422 | } |
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| 423 | |||
| 424 | public function waitForAll( $pos, $timeout = null ) { |
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| 425 | $this->mWaitForPos = $pos; |
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| 426 | $serverCount = count( $this->mServers ); |
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| 427 | |||
| 428 | $ok = true; |
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| 429 | for ( $i = 1; $i < $serverCount; $i++ ) { |
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| 430 | View Code Duplication | if ( $this->mLoads[$i] > 0 ) { |
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| 431 | $ok = $this->doWait( $i, true, $timeout ) && $ok; |
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| 432 | } |
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| 433 | } |
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| 434 | |||
| 435 | return $ok; |
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| 436 | } |
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| 437 | |||
| 438 | public function getAnyOpenConnection( $i ) { |
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| 439 | foreach ( $this->mConns as $connsByServer ) { |
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| 440 | if ( !empty( $connsByServer[$i] ) ) { |
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| 441 | return reset( $connsByServer[$i] ); |
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| 442 | } |
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| 443 | } |
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| 444 | |||
| 445 | return false; |
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| 446 | } |
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| 447 | |||
| 448 | /** |
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| 449 | * Wait for a given replica DB to catch up to the master pos stored in $this |
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| 450 | * @param int $index Server index |
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| 451 | * @param bool $open Check the server even if a new connection has to be made |
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| 452 | * @param int $timeout Max seconds to wait; default is mWaitTimeout |
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| 453 | * @return bool |
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| 454 | */ |
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| 455 | protected function doWait( $index, $open = false, $timeout = null ) { |
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| 456 | $close = false; // close the connection afterwards |
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| 457 | |||
| 458 | // Check if we already know that the DB has reached this point |
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| 459 | $server = $this->getServerName( $index ); |
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| 460 | $key = $this->srvCache->makeGlobalKey( __CLASS__, 'last-known-pos', $server ); |
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| 461 | /** @var DBMasterPos $knownReachedPos */ |
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| 462 | $knownReachedPos = $this->srvCache->get( $key ); |
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| 463 | if ( $knownReachedPos && $knownReachedPos->hasReached( $this->mWaitForPos ) ) { |
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| 464 | $this->replLogger->debug( __METHOD__ . |
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| 465 | ": replica DB $server known to be caught up (pos >= $knownReachedPos)." ); |
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| 466 | return true; |
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| 467 | } |
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| 468 | |||
| 469 | // Find a connection to wait on, creating one if needed and allowed |
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| 470 | $conn = $this->getAnyOpenConnection( $index ); |
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| 471 | if ( !$conn ) { |
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| 472 | if ( !$open ) { |
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| 473 | $this->replLogger->debug( __METHOD__ . ": no connection open for $server" ); |
||
| 474 | |||
| 475 | return false; |
||
| 476 | } else { |
||
| 477 | $conn = $this->openConnection( $index, self::DOMAIN_ANY ); |
||
| 478 | if ( !$conn ) { |
||
| 479 | $this->replLogger->warning( __METHOD__ . ": failed to connect to $server" ); |
||
| 480 | |||
| 481 | return false; |
||
| 482 | } |
||
| 483 | // Avoid connection spam in waitForAll() when connections |
||
| 484 | // are made just for the sake of doing this lag check. |
||
| 485 | $close = true; |
||
| 486 | } |
||
| 487 | } |
||
| 488 | |||
| 489 | $this->replLogger->info( __METHOD__ . ": Waiting for replica DB $server to catch up..." ); |
||
| 490 | $timeout = $timeout ?: $this->mWaitTimeout; |
||
| 491 | $result = $conn->masterPosWait( $this->mWaitForPos, $timeout ); |
||
| 492 | |||
| 493 | if ( $result == -1 || is_null( $result ) ) { |
||
| 494 | // Timed out waiting for replica DB, use master instead |
||
| 495 | $msg = __METHOD__ . ": Timed out waiting on $server pos {$this->mWaitForPos}"; |
||
| 496 | $this->replLogger->warning( "$msg" ); |
||
| 497 | $ok = false; |
||
| 498 | } else { |
||
| 499 | $this->replLogger->info( __METHOD__ . ": Done" ); |
||
| 500 | $ok = true; |
||
| 501 | // Remember that the DB reached this point |
||
| 502 | $this->srvCache->set( $key, $this->mWaitForPos, BagOStuff::TTL_DAY ); |
||
| 503 | } |
||
| 504 | |||
| 505 | if ( $close ) { |
||
| 506 | $this->closeConnection( $conn ); |
||
| 507 | } |
||
| 508 | |||
| 509 | return $ok; |
||
| 510 | } |
||
| 511 | |||
| 512 | /** |
||
| 513 | * @see ILoadBalancer::getConnection() |
||
| 514 | * |
||
| 515 | * @param int $i |
||
| 516 | * @param array $groups |
||
| 517 | * @param bool $domain |
||
| 518 | * @return Database |
||
| 519 | * @throws DBConnectionError |
||
| 520 | */ |
||
| 521 | public function getConnection( $i, $groups = [], $domain = false ) { |
||
| 522 | if ( $i === null || $i === false ) { |
||
| 523 | throw new InvalidArgumentException( 'Attempt to call ' . __METHOD__ . |
||
| 524 | ' with invalid server index' ); |
||
| 525 | } |
||
| 526 | |||
| 527 | if ( $this->localDomain->equals( $domain ) || $domain === $this->localDomainIdAlias ) { |
||
| 528 | $domain = false; // local connection requested |
||
| 529 | } |
||
| 530 | |||
| 531 | $groups = ( $groups === false || $groups === [] ) |
||
| 532 | ? [ false ] // check one "group": the generic pool |
||
| 533 | : (array)$groups; |
||
| 534 | |||
| 535 | $masterOnly = ( $i == self::DB_MASTER || $i == $this->getWriterIndex() ); |
||
| 536 | $oldConnsOpened = $this->connsOpened; // connections open now |
||
| 537 | |||
| 538 | if ( $i == self::DB_MASTER ) { |
||
| 539 | $i = $this->getWriterIndex(); |
||
| 540 | } else { |
||
| 541 | # Try to find an available server in any the query groups (in order) |
||
| 542 | foreach ( $groups as $group ) { |
||
| 543 | $groupIndex = $this->getReaderIndex( $group, $domain ); |
||
| 544 | if ( $groupIndex !== false ) { |
||
| 545 | $i = $groupIndex; |
||
| 546 | break; |
||
| 547 | } |
||
| 548 | } |
||
| 549 | } |
||
| 550 | |||
| 551 | # Operation-based index |
||
| 552 | if ( $i == self::DB_REPLICA ) { |
||
| 553 | $this->mLastError = 'Unknown error'; // reset error string |
||
| 554 | # Try the general server pool if $groups are unavailable. |
||
| 555 | $i = in_array( false, $groups, true ) |
||
| 556 | ? false // don't bother with this if that is what was tried above |
||
| 557 | : $this->getReaderIndex( false, $domain ); |
||
| 558 | # Couldn't find a working server in getReaderIndex()? |
||
| 559 | if ( $i === false ) { |
||
| 560 | $this->mLastError = 'No working replica DB server: ' . $this->mLastError; |
||
| 561 | // Throw an exception |
||
| 562 | $this->reportConnectionError(); |
||
| 563 | return null; // not reached |
||
| 564 | } |
||
| 565 | } |
||
| 566 | |||
| 567 | # Now we have an explicit index into the servers array |
||
| 568 | $conn = $this->openConnection( $i, $domain ); |
||
| 569 | if ( !$conn ) { |
||
| 570 | // Throw an exception |
||
| 571 | $this->reportConnectionError(); |
||
| 572 | return null; // not reached |
||
| 573 | } |
||
| 574 | |||
| 575 | # Profile any new connections that happen |
||
| 576 | if ( $this->connsOpened > $oldConnsOpened ) { |
||
| 577 | $host = $conn->getServer(); |
||
| 578 | $dbname = $conn->getDBname(); |
||
| 579 | $this->trxProfiler->recordConnection( $host, $dbname, $masterOnly ); |
||
| 580 | } |
||
| 581 | |||
| 582 | if ( $masterOnly ) { |
||
| 583 | # Make master-requested DB handles inherit any read-only mode setting |
||
| 584 | $conn->setLBInfo( 'readOnlyReason', $this->getReadOnlyReason( $domain, $conn ) ); |
||
| 585 | } |
||
| 586 | |||
| 587 | return $conn; |
||
| 588 | } |
||
| 589 | |||
| 590 | public function reuseConnection( $conn ) { |
||
| 591 | $serverIndex = $conn->getLBInfo( 'serverIndex' ); |
||
| 592 | $refCount = $conn->getLBInfo( 'foreignPoolRefCount' ); |
||
| 593 | if ( $serverIndex === null || $refCount === null ) { |
||
| 594 | /** |
||
| 595 | * This can happen in code like: |
||
| 596 | * foreach ( $dbs as $db ) { |
||
| 597 | * $conn = $lb->getConnection( $lb::DB_REPLICA, [], $db ); |
||
| 598 | * ... |
||
| 599 | * $lb->reuseConnection( $conn ); |
||
| 600 | * } |
||
| 601 | * When a connection to the local DB is opened in this way, reuseConnection() |
||
| 602 | * should be ignored |
||
| 603 | */ |
||
| 604 | return; |
||
| 605 | } elseif ( $conn instanceof DBConnRef ) { |
||
| 606 | // DBConnRef already handles calling reuseConnection() and only passes the live |
||
| 607 | // Database instance to this method. Any caller passing in a DBConnRef is broken. |
||
| 608 | $this->connLogger->error( __METHOD__ . ": got DBConnRef instance.\n" . |
||
| 609 | ( new RuntimeException() )->getTraceAsString() ); |
||
| 610 | |||
| 611 | return; |
||
| 612 | } |
||
| 613 | |||
| 614 | if ( $this->disabled ) { |
||
| 615 | return; // DBConnRef handle probably survived longer than the LoadBalancer |
||
| 616 | } |
||
| 617 | |||
| 618 | $domain = $conn->getDomainID(); |
||
| 619 | if ( !isset( $this->mConns['foreignUsed'][$serverIndex][$domain] ) ) { |
||
| 620 | throw new InvalidArgumentException( __METHOD__ . |
||
| 621 | ": connection $serverIndex/$domain not found; it may have already been freed." ); |
||
| 622 | } elseif ( $this->mConns['foreignUsed'][$serverIndex][$domain] !== $conn ) { |
||
| 623 | throw new InvalidArgumentException( __METHOD__ . |
||
| 624 | ": connection $serverIndex/$domain mismatched; it may have already been freed." ); |
||
| 625 | } |
||
| 626 | $conn->setLBInfo( 'foreignPoolRefCount', --$refCount ); |
||
| 627 | if ( $refCount <= 0 ) { |
||
| 628 | $this->mConns['foreignFree'][$serverIndex][$domain] = $conn; |
||
| 629 | unset( $this->mConns['foreignUsed'][$serverIndex][$domain] ); |
||
| 630 | if ( !$this->mConns['foreignUsed'][$serverIndex] ) { |
||
| 631 | unset( $this->mConns[ 'foreignUsed' ][$serverIndex] ); // clean up |
||
| 632 | } |
||
| 633 | $this->connLogger->debug( __METHOD__ . ": freed connection $serverIndex/$domain" ); |
||
| 634 | } else { |
||
| 635 | $this->connLogger->debug( __METHOD__ . |
||
| 636 | ": reference count for $serverIndex/$domain reduced to $refCount" ); |
||
| 637 | } |
||
| 638 | } |
||
| 639 | |||
| 640 | public function getConnectionRef( $db, $groups = [], $domain = false ) { |
||
| 641 | $domain = ( $domain !== false ) ? $domain : $this->localDomain; |
||
| 642 | |||
| 643 | return new DBConnRef( $this, $this->getConnection( $db, $groups, $domain ) ); |
||
| 644 | } |
||
| 645 | |||
| 646 | public function getLazyConnectionRef( $db, $groups = [], $domain = false ) { |
||
| 651 | |||
| 652 | /** |
||
| 653 | * @see ILoadBalancer::openConnection() |
||
| 654 | * |
||
| 655 | * @param int $i |
||
| 656 | * @param bool $domain |
||
| 657 | * @return bool|Database |
||
| 658 | * @throws DBAccessError |
||
| 659 | */ |
||
| 660 | public function openConnection( $i, $domain = false ) { |
||
| 661 | if ( $this->localDomain->equals( $domain ) || $domain === $this->localDomainIdAlias ) { |
||
| 662 | $domain = false; // local connection requested |
||
| 663 | } |
||
| 699 | |||
| 700 | /** |
||
| 701 | * Open a connection to a foreign DB, or return one if it is already open. |
||
| 702 | * |
||
| 703 | * Increments a reference count on the returned connection which locks the |
||
| 704 | * connection to the requested domain. This reference count can be |
||
| 705 | * decremented by calling reuseConnection(). |
||
| 706 | * |
||
| 707 | * If a connection is open to the appropriate server already, but with the wrong |
||
| 708 | * database, it will be switched to the right database and returned, as long as |
||
| 709 | * it has been freed first with reuseConnection(). |
||
| 710 | * |
||
| 711 | * On error, returns false, and the connection which caused the |
||
| 712 | * error will be available via $this->mErrorConnection. |
||
| 713 | * |
||
| 714 | * @note If disable() was called on this LoadBalancer, this method will throw a DBAccessError. |
||
| 715 | * |
||
| 716 | * @param int $i Server index |
||
| 717 | * @param string $domain Domain ID to open |
||
| 718 | * @return Database |
||
| 719 | */ |
||
| 720 | private function openForeignConnection( $i, $domain ) { |
||
| 782 | |||
| 783 | /** |
||
| 784 | * Test if the specified index represents an open connection |
||
| 785 | * |
||
| 786 | * @param int $index Server index |
||
| 787 | * @access private |
||
| 788 | * @return bool |
||
| 789 | */ |
||
| 790 | private function isOpen( $index ) { |
||
| 797 | |||
| 798 | /** |
||
| 799 | * Really opens a connection. Uncached. |
||
| 800 | * Returns a Database object whether or not the connection was successful. |
||
| 801 | * @access private |
||
| 802 | * |
||
| 803 | * @param array $server |
||
| 804 | * @param string|bool $dbNameOverride Use "" to not select any database |
||
| 805 | * @return Database |
||
| 806 | * @throws DBAccessError |
||
| 807 | * @throws InvalidArgumentException |
||
| 808 | */ |
||
| 809 | protected function reallyOpenConnection( array $server, $dbNameOverride = false ) { |
||
| 868 | |||
| 869 | /** |
||
| 870 | * @throws DBConnectionError |
||
| 871 | */ |
||
| 872 | private function reportConnectionError() { |
||
| 899 | |||
| 900 | public function getWriterIndex() { |
||
| 903 | |||
| 904 | public function haveIndex( $i ) { |
||
| 907 | |||
| 908 | public function isNonZeroLoad( $i ) { |
||
| 911 | |||
| 912 | public function getServerCount() { |
||
| 915 | |||
| 916 | public function getServerName( $i ) { |
||
| 927 | |||
| 928 | public function getServerInfo( $i ) { |
||
| 935 | |||
| 936 | public function setServerInfo( $i, array $serverInfo ) { |
||
| 939 | |||
| 940 | public function getMasterPos() { |
||
| 958 | |||
| 959 | public function disable() { |
||
| 963 | |||
| 964 | public function closeAll() { |
||
| 978 | |||
| 979 | public function closeConnection( IDatabase $conn ) { |
||
| 999 | |||
| 1000 | public function commitAll( $fname = __METHOD__ ) { |
||
| 1026 | |||
| 1027 | public function finalizeMasterChanges() { |
||
| 1036 | |||
| 1037 | public function approveMasterChanges( array $options ) { |
||
| 1069 | |||
| 1070 | public function beginMasterChanges( $fname = __METHOD__ ) { |
||
| 1101 | |||
| 1102 | public function commitMasterChanges( $fname = __METHOD__ ) { |
||
| 1135 | |||
| 1136 | public function runMasterPostTrxCallbacks( $type ) { |
||
| 1168 | |||
| 1169 | public function rollbackMasterChanges( $fname = __METHOD__ ) { |
||
| 1183 | |||
| 1184 | public function suppressTransactionEndCallbacks() { |
||
| 1189 | |||
| 1190 | /** |
||
| 1191 | * @param IDatabase $conn |
||
| 1192 | */ |
||
| 1193 | private function applyTransactionRoundFlags( IDatabase $conn ) { |
||
| 1203 | |||
| 1204 | /** |
||
| 1205 | * @param IDatabase $conn |
||
| 1206 | */ |
||
| 1207 | private function undoTransactionRoundFlags( IDatabase $conn ) { |
||
| 1212 | |||
| 1213 | public function flushReplicaSnapshots( $fname = __METHOD__ ) { |
||
| 1218 | |||
| 1219 | public function hasMasterConnection() { |
||
| 1222 | |||
| 1223 | public function hasMasterChanges() { |
||
| 1231 | |||
| 1232 | public function lastMasterChangeTimestamp() { |
||
| 1240 | |||
| 1241 | public function hasOrMadeRecentMasterChanges( $age = null ) { |
||
| 1247 | |||
| 1248 | public function pendingMasterChangeCallers() { |
||
| 1256 | |||
| 1257 | public function getLaggedReplicaMode( $domain = false ) { |
||
| 1273 | |||
| 1274 | /** |
||
| 1275 | * @param bool $domain |
||
| 1276 | * @return bool |
||
| 1277 | * @deprecated 1.28; use getLaggedReplicaMode() |
||
| 1278 | */ |
||
| 1279 | public function getLaggedSlaveMode( $domain = false ) { |
||
| 1282 | |||
| 1283 | public function laggedReplicaUsed() { |
||
| 1286 | |||
| 1287 | /** |
||
| 1288 | * @return bool |
||
| 1289 | * @since 1.27 |
||
| 1290 | * @deprecated Since 1.28; use laggedReplicaUsed() |
||
| 1291 | */ |
||
| 1292 | public function laggedSlaveUsed() { |
||
| 1295 | |||
| 1296 | public function getReadOnlyReason( $domain = false, IDatabase $conn = null ) { |
||
| 1313 | |||
| 1314 | /** |
||
| 1315 | * @param string $domain Domain ID, or false for the current domain |
||
| 1316 | * @param IDatabase|null DB master connectionl used to avoid loops [optional] |
||
| 1317 | * @return bool |
||
| 1318 | */ |
||
| 1319 | private function masterRunningReadOnly( $domain, IDatabase $conn = null ) { |
||
| 1343 | |||
| 1344 | public function allowLagged( $mode = null ) { |
||
| 1352 | |||
| 1353 | public function pingAll() { |
||
| 1363 | |||
| 1364 | View Code Duplication | public function forEachOpenConnection( $callback, array $params = [] ) { |
|
| 1374 | |||
| 1375 | public function forEachOpenMasterConnection( $callback, array $params = [] ) { |
||
| 1387 | |||
| 1388 | View Code Duplication | public function forEachOpenReplicaConnection( $callback, array $params = [] ) { |
|
| 1401 | |||
| 1402 | public function getMaxLag( $domain = false ) { |
||
| 1422 | |||
| 1423 | public function getLagTimes( $domain = false ) { |
||
| 1440 | |||
| 1441 | public function safeGetLag( IDatabase $conn ) { |
||
| 1448 | |||
| 1449 | public function safeWaitForMasterPos( IDatabase $conn, $pos = false, $timeout = 10 ) { |
||
| 1483 | |||
| 1484 | public function setTransactionListener( $name, callable $callback = null ) { |
||
| 1496 | |||
| 1497 | public function setTableAliases( array $aliases ) { |
||
| 1500 | |||
| 1501 | public function setDomainPrefix( $prefix ) { |
||
| 1523 | |||
| 1524 | /** |
||
| 1525 | * Make PHP ignore user aborts/disconnects until the returned |
||
| 1526 | * value leaves scope. This returns null and does nothing in CLI mode. |
||
| 1527 | * |
||
| 1528 | * @return ScopedCallback|null |
||
| 1529 | */ |
||
| 1530 | View Code Duplication | final protected function getScopedPHPBehaviorForCommit() { |
|
| 1540 | |||
| 1541 | function __destruct() { |
||
| 1545 | } |
||
| 1546 |
Loading history...
Our type inference engine has found an assignment to a property that is incompatible with the declared type of that property.
Either this assignment is in error or the assigned type should be added to the documentation/type hint for that property..