* @param string|bool $cluster Cluster name accepted by LBFactory. Default: false.
* @param int|null $timeout Max wait time. Default: 1 day (cli), ~10 seconds (web)
* @return bool Success (able to connect and no timeouts reached)
+ * @deprecated since 1.27 Use LBFactory::waitForReplication
*/
function wfWaitForSlaves(
$ifWritesSince = null, $wiki = false, $cluster = false, $timeout = null
) {
- // B/C: first argument used to be "max seconds of lag"; ignore such values
- $ifWritesSince = ( $ifWritesSince > 1e9 ) ? $ifWritesSince : null;
-
if ( $timeout === null ) {
$timeout = ( PHP_SAPI === 'cli' ) ? 86400 : 10;
}
- // Figure out which clusters need to be checked
- /** @var LoadBalancer[] $lbs */
- $lbs = array();
if ( $cluster === '*' ) {
- wfGetLBFactory()->forEachLB( function ( LoadBalancer $lb ) use ( &$lbs ) {
- $lbs[] = $lb;
- } );
- } elseif ( $cluster !== false ) {
- $lbs[] = wfGetLBFactory()->getExternalLB( $cluster );
- } else {
- $lbs[] = wfGetLB( $wiki );
- }
-
- // Get all the master positions of applicable DBs right now.
- // This can be faster since waiting on one cluster reduces the
- // time needed to wait on the next clusters.
- $masterPositions = array_fill( 0, count( $lbs ), false );
- foreach ( $lbs as $i => $lb ) {
- if ( $lb->getServerCount() <= 1 ) {
- // Bug 27975 - Don't try to wait for slaves if there are none
- // Prevents permission error when getting master position
- continue;
- } elseif ( $ifWritesSince && $lb->lastMasterChangeTimestamp() < $ifWritesSince ) {
- continue; // no writes since the last wait
- }
- $masterPositions[$i] = $lb->getMasterPos();
+ $cluster = false;
+ $wiki = false;
+ } elseif ( $wiki === false ) {
+ $wiki = wfWikiID();
}
- $ok = true;
- foreach ( $lbs as $i => $lb ) {
- if ( $masterPositions[$i] ) {
- // The DBMS may not support getMasterPos() or the whole
- // load balancer might be fake (e.g. $wgAllDBsAreLocalhost).
- $ok = $lb->waitForAll( $masterPositions[$i], $timeout ) && $ok;
- }
+ try {
+ wfGetLBFactory()->waitForReplication( array(
+ 'wiki' => $wiki,
+ 'cluster' => $cluster,
+ 'timeout' => $timeout,
+ // B/C: first argument used to be "max seconds of lag"; ignore such values
+ 'ifWritesSince' => ( $ifWritesSince > 1e9 ) ? $ifWritesSince : null
+ ) );
+ } catch ( DBReplicationWaitError $e ) {
+ return false;
}
- return $ok;
+ return true;
}
/**
return $ret;
}
+ /**
+ * Waits for the slave DBs to catch up to the current master position
+ *
+ * Use this when updating very large numbers of rows, as in maintenance scripts,
+ * to avoid causing too much lag. Of course, this is a no-op if there are no slaves.
+ *
+ * By default this waits on all DB clusters actually used in this request.
+ * This makes sense when lag being waiting on is caused by the code that does this check.
+ * In that case, setting "ifWritesSince" can avoid the overhead of waiting for clusters
+ * that were not changed since the last wait check. To forcefully wait on a specific cluster
+ * for a given wiki, use the 'wiki' parameter. To forcefully wait on an "external" cluster,
+ * use the "cluster" parameter.
+ *
+ * Never call this function after a large DB write that is *still* in a transaction.
+ * It only makes sense to call this after the possible lag inducing changes were committed.
+ *
+ * @param array $opts Optional fields that include:
+ * - wiki : wait on the load balancer DBs that handles the given wiki
+ * - cluster : wait on the given external load balancer DBs
+ * - timeout : Max wait time. Default: ~60 seconds
+ * - ifWritesSince: Only wait if writes were done since this UNIX timestamp
+ * @throws DBReplicationWaitError If a timeout or error occured waiting on a DB cluster
+ * @since 1.27
+ */
+ public function waitForReplication( array $opts = array() ) {
+ $opts += array(
+ 'wiki' => false,
+ 'cluster' => false,
+ 'timeout' => 60,
+ 'ifWritesSince' => null
+ );
+
+ // Figure out which clusters need to be checked
+ /** @var LoadBalancer[] $lbs */
+ $lbs = array();
+ if ( $opts['cluster'] !== false ) {
+ $lbs[] = $this->getExternalLB( $opts['cluster'] );
+ } elseif ( $opts['wiki'] !== false ) {
+ $lbs[] = $this->getMainLB( $opts['wiki'] );
+ } else {
+ $this->forEachLB( function ( LoadBalancer $lb ) use ( &$lbs ) {
+ $lbs[] = $lb;
+ } );
+ if ( !$lbs ) {
+ return; // nothing actually used
+ }
+ }
+
+ // Get all the master positions of applicable DBs right now.
+ // This can be faster since waiting on one cluster reduces the
+ // time needed to wait on the next clusters.
+ $masterPositions = array_fill( 0, count( $lbs ), false );
+ foreach ( $lbs as $i => $lb ) {
+ if ( $lb->getServerCount() <= 1 ) {
+ // Bug 27975 - Don't try to wait for slaves if there are none
+ // Prevents permission error when getting master position
+ continue;
+ } elseif ( $opts['ifWritesSince']
+ && $lb->lastMasterChangeTimestamp() < $opts['ifWritesSince']
+ ) {
+ continue; // no writes since the last wait
+ }
+ $masterPositions[$i] = $lb->getMasterPos();
+ }
+
+ $failed = array();
+ foreach ( $lbs as $i => $lb ) {
+ if ( $masterPositions[$i] ) {
+ // The DBMS may not support getMasterPos() or the whole
+ // load balancer might be fake (e.g. $wgAllDBsAreLocalhost).
+ if ( !$lb->waitForAll( $masterPositions[$i], $opts['timeout'] ) ) {
+ $failed[] = $lb->getServerName( $lb->getWriterIndex() );
+ }
+ }
+ }
+
+ if ( $failed ) {
+ throw new DBReplicationWaitError(
+ "Could not wait for slaves to catch up to " .
+ implode( ', ', $failed )
+ );
+ }
+ }
+
/**
* Disable the ChronologyProtector for all load balancers
*
"This is not allowed." );
}
}
+
+/**
+ * Exception class for replica DB wait timeouts
+ */
+class DBReplicationWaitError extends Exception {
+}
dépôts / lhc / web / wiklou.git / commitdiff