/** @var string Storage key name */
protected $key;
- /** @var array Map of (ip: <IP>, agent: <user-agent>) */
- protected $client;
+ /** @var string Hash of client parameters */
+ protected $clientId;
/** @var bool Whether to no-op all method calls */
protected $enabled = true;
/** @var bool Whether to check and wait on positions */
/** @var bool Whether the client data was loaded */
protected $initialized = false;
/** @var DBMasterPos[] Map of (DB master name => position) */
- protected $startupPositions = array();
+ protected $startupPositions = [];
/** @var DBMasterPos[] Map of (DB master name => position) */
- protected $shutdownPositions = array();
+ protected $shutdownPositions = [];
+ /** @var float[] Map of (DB master name => 1) */
+ protected $shutdownTouchDBs = [];
/**
* @param BagOStuff $store
*/
public function __construct( BagOStuff $store, array $client ) {
$this->store = $store;
- $this->client = $client;
- $this->key = $store->makeGlobalKey(
- 'ChronologyProtector',
- md5( $client['ip'] . "\n" . $client['agent'] )
- );
+ $this->clientId = md5( $client['ip'] . "\n" . $client['agent'] );
+ $this->key = $store->makeGlobalKey( __CLASS__, $this->clientId );
}
/**
* Initialise a LoadBalancer to give it appropriate chronology protection.
*
* If the stash has a previous master position recorded, this will try to
- * make sure that the next query to a slave of that master will see changes up
+ * make sure that the next query to a replica DB of that master will see changes up
* to that position by delaying execution. The delay may timeout and allow stale
- * data if no non-lagged slaves are available.
+ * data if no non-lagged replica DBs are available.
*
* @param LoadBalancer $lb
* @return void
$masterName = $lb->getServerName( $lb->getWriterIndex() );
if ( !empty( $this->startupPositions[$masterName] ) ) {
- $info = $lb->parentInfo();
$pos = $this->startupPositions[$masterName];
- wfDebugLog( 'replication', __METHOD__ .
- ": LB '" . $info['id'] . "' waiting for master pos $pos\n" );
+ wfDebugLog( 'replication', __METHOD__ . ": LB for '$masterName' set to pos $pos\n" );
$lb->waitFor( $pos );
}
}
* @return void
*/
public function shutdownLB( LoadBalancer $lb ) {
- if ( !$this->enabled || $lb->getServerCount() <= 1 ) {
- return; // non-replicated setup or disabled
+ if ( !$this->enabled ) {
+ return; // not enabled
+ } elseif ( !$lb->hasOrMadeRecentMasterChanges( INF ) ) {
+ // Only save the position if writes have been done on the connection
+ return;
}
- $info = $lb->parentInfo();
$masterName = $lb->getServerName( $lb->getWriterIndex() );
-
- // Only save the position if writes have been done on the connection
- $db = $lb->getAnyOpenConnection( $lb->getWriterIndex() );
- if ( !$db || !$db->doneWrites() ) {
- wfDebugLog( 'replication', __METHOD__ . ": LB {$info['id']}, no writes done\n" );
-
- return; // nothing to do
+ if ( $lb->getServerCount() > 1 ) {
+ $pos = $lb->getMasterPos();
+ wfDebugLog( 'replication', __METHOD__ . ": LB for '$masterName' has pos $pos\n" );
+ $this->shutdownPositions[$masterName] = $pos;
+ } else {
+ wfDebugLog( 'replication', __METHOD__ . ": DB '$masterName' touched\n" );
}
-
- $pos = $db->getMasterPos();
- wfDebugLog( 'replication', __METHOD__ . ": LB {$info['id']} has master pos $pos\n" );
- $this->shutdownPositions[$masterName] = $pos;
+ $this->shutdownTouchDBs[$masterName] = 1;
}
/**
* Notify the ChronologyProtector that the LBFactory is done calling shutdownLB() for now.
* May commit chronology data to persistent storage.
*
- * @return array Empty on success; returns the (db name => position) map on failure
+ * @return DBMasterPos[] Empty on success; returns the (db name => position) map on failure
*/
public function shutdown() {
- if ( !$this->enabled || !count( $this->shutdownPositions ) ) {
- return true; // nothing to save
+ if ( !$this->enabled ) {
+ return [];
+ }
+
+ // Some callers might want to know if a user recently touched a DB.
+ // These writes do not need to block on all datacenters receiving them.
+ foreach ( $this->shutdownTouchDBs as $dbName => $unused ) {
+ $this->store->set(
+ $this->getTouchedKey( $this->store, $dbName ),
+ microtime( true ),
+ BagOStuff::TTL_DAY
+ );
+ }
+
+ if ( !count( $this->shutdownPositions ) ) {
+ return []; // nothing to save
}
wfDebugLog( 'replication',
implode( ', ', array_keys( $this->shutdownPositions ) ) . "\n"
);
- $shutdownPositions = $this->shutdownPositions;
- $ok = $this->store->merge(
- $this->key,
- function ( $store, $key, $curValue ) use ( $shutdownPositions ) {
- /** @var $curPositions DBMasterPos[] */
- if ( $curValue === false ) {
- $curPositions = $shutdownPositions;
- } else {
- $curPositions = $curValue['positions'];
- // Use the newest positions for each DB master
- foreach ( $shutdownPositions as $db => $pos ) {
- if ( !isset( $curPositions[$db] )
- || $pos->asOfTime() > $curPositions[$db]->asOfTime()
- ) {
- $curPositions[$db] = $pos;
- }
- }
- }
-
- return array( 'positions' => $curPositions );
- },
- BagOStuff::TTL_MINUTE,
- 10,
- BagOStuff::WRITE_SYNC // visible in all datacenters
- );
+ // CP-protected writes should overwhemingly go to the master datacenter, so get DC-local
+ // lock to merge the values. Use a DC-local get() and a synchronous all-DC set(). This
+ // makes it possible for the BagOStuff class to write in parallel to all DCs with one RTT.
+ if ( $this->store->lock( $this->key, 3 ) ) {
+ $ok = $this->store->set(
+ $this->key,
+ self::mergePositions( $this->store->get( $this->key ), $this->shutdownPositions ),
+ BagOStuff::TTL_MINUTE,
+ BagOStuff::WRITE_SYNC
+ );
+ $this->store->unlock( $this->key );
+ } else {
+ $ok = false;
+ }
if ( !$ok ) {
// Raced out too many times or stash is down
return $this->shutdownPositions;
}
- return array();
+ return [];
+ }
+
+ /**
+ * @param string $dbName DB master name (e.g. "db1052")
+ * @return float|bool UNIX timestamp when client last touched the DB; false if not on record
+ * @since 1.28
+ */
+ public function getTouched( $dbName ) {
+ return $this->store->get( $this->getTouchedKey( $this->store, $dbName ) );
+ }
+
+ /**
+ * @param BagOStuff $store
+ * @param string $dbName
+ * @return string
+ */
+ private function getTouchedKey( BagOStuff $store, $dbName ) {
+ return $store->makeGlobalKey( __CLASS__, 'mtime', $this->clientId, $dbName );
}
/**
$this->initialized = true;
if ( $this->wait ) {
$data = $this->store->get( $this->key );
- $this->startupPositions = $data ? $data['positions'] : array();
-
+ $this->startupPositions = $data ? $data['positions'] : [];
wfDebugLog( 'replication', __METHOD__ . ": key is {$this->key} (read)\n" );
} else {
- $this->startupPositions = array();
-
+ $this->startupPositions = [];
wfDebugLog( 'replication', __METHOD__ . ": key is {$this->key} (unread)\n" );
}
}
+
+ /**
+ * @param array|bool $curValue
+ * @param DBMasterPos[] $shutdownPositions
+ * @return array
+ */
+ private static function mergePositions( $curValue, array $shutdownPositions ) {
+ /** @var $curPositions DBMasterPos[] */
+ if ( $curValue === false ) {
+ $curPositions = $shutdownPositions;
+ } else {
+ $curPositions = $curValue['positions'];
+ // Use the newest positions for each DB master
+ foreach ( $shutdownPositions as $db => $pos ) {
+ if ( !isset( $curPositions[$db] )
+ || $pos->asOfTime() > $curPositions[$db]->asOfTime()
+ ) {
+ $curPositions[$db] = $pos;
+ }
+ }
+ }
+
+ return [ 'positions' => $curPositions ];
+ }
}
dépôts / lhc / web / wiklou.git / blobdiff