Removed unused postConnectionBackoff() from LoadMonitor
* This setting proved to be not terrible useful Change-Id: I58b18947ff0edb8937229d0f130d7d10e846125e
This commit is contained in:
Aaron Schulz
parent
717f428d64
commit
b3c9653090
4 changed files with 48 additions and 127 deletions
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@ -31,6 +31,7 @@ production.
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* $wgPasswordSenderName has been deprecated. To set a custom mailer name,
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the system message 'emailsender' should be modified (default: "{{SITENAME}}").
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* $wgDBAhandler was removed as the only class using it was also removed
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* The 'max threads' setting was removed from $wgDBservers.
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=== New features in 1.23 ===
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* ResourceLoader can utilize the Web Storage API to cache modules client-side.
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@ -1654,7 +1654,6 @@ $wgSharedTables = array( 'user', 'user_properties' );
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* if available
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*
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* - max lag: (optional) Maximum replication lag before a slave will taken out of rotation
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* - max threads: (optional) Maximum number of running threads
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*
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* These and any other user-defined properties will be assigned to the mLBInfo member
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* variable of the Database object.
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@ -188,7 +188,7 @@ class LoadBalancer {
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* @return bool|int|string
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*/
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function getReaderIndex( $group = false, $wiki = false ) {
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global $wgReadOnly, $wgDBClusterTimeout, $wgDBAvgStatusPoll, $wgDBtype;
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global $wgReadOnly, $wgDBtype;
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# @todo FIXME: For now, only go through all this for mysql databases
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if ( $wgDBtype != 'mysql' ) {
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@ -198,18 +198,13 @@ class LoadBalancer {
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if ( count( $this->mServers ) == 1 ) {
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# Skip the load balancing if there's only one server
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return 0;
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} elseif ( $group === false and $this->mReadIndex >= 0 ) {
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} elseif ( $group === false && $this->mReadIndex >= 0 ) {
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# Shortcut if generic reader exists already
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return $this->mReadIndex;
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}
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wfProfileIn( __METHOD__ );
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$totalElapsed = 0;
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# convert from seconds to microseconds
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$timeout = $wgDBClusterTimeout * 1e6;
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# Find the relevant load array
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if ( $group !== false ) {
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if ( isset( $this->mGroupLoads[$group] ) ) {
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@ -225,7 +220,7 @@ class LoadBalancer {
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$nonErrorLoads = $this->mLoads;
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}
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if ( !$nonErrorLoads ) {
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if ( !count( $nonErrorLoads ) ) {
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wfProfileOut( __METHOD__ );
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throw new MWException( "Empty server array given to LoadBalancer" );
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}
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@ -235,93 +230,60 @@ class LoadBalancer {
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$laggedSlaveMode = false;
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# No server found yet
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$i = false;
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# First try quickly looking through the available servers for a server that
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# meets our criteria
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do {
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$totalThreadsConnected = 0;
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$overloadedServers = 0;
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$currentLoads = $nonErrorLoads;
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while ( count( $currentLoads ) ) {
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if ( $wgReadOnly || $this->mAllowLagged || $laggedSlaveMode ) {
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$currentLoads = $nonErrorLoads;
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while ( count( $currentLoads ) ) {
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if ( $wgReadOnly || $this->mAllowLagged || $laggedSlaveMode ) {
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$i = ArrayUtils::pickRandom( $currentLoads );
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} else {
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$i = $this->getRandomNonLagged( $currentLoads, $wiki );
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if ( $i === false && count( $currentLoads ) != 0 ) {
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# All slaves lagged. Switch to read-only mode
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wfDebugLog( 'replication', "All slaves lagged. Switch to read-only mode\n" );
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$wgReadOnly = 'The database has been automatically locked ' .
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'while the slave database servers catch up to the master';
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$i = ArrayUtils::pickRandom( $currentLoads );
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} else {
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$i = $this->getRandomNonLagged( $currentLoads, $wiki );
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if ( $i === false && count( $currentLoads ) != 0 ) {
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# All slaves lagged. Switch to read-only mode
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wfDebugLog( 'replication', "All slaves lagged. Switch to read-only mode\n" );
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$wgReadOnly = 'The database has been automatically locked ' .
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'while the slave database servers catch up to the master';
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$i = ArrayUtils::pickRandom( $currentLoads );
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$laggedSlaveMode = true;
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}
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}
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if ( $i === false ) {
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# pickRandom() returned false
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# This is permanent and means the configuration or the load monitor
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# wants us to return false.
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wfDebugLog( 'connect', __METHOD__ . ": pickRandom() returned false\n" );
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wfProfileOut( __METHOD__ );
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return false;
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}
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wfDebugLog( 'connect', __METHOD__ . ": Using reader #$i: {$this->mServers[$i]['host']}...\n" );
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$conn = $this->openConnection( $i, $wiki );
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if ( !$conn ) {
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wfDebugLog( 'connect', __METHOD__ . ": Failed connecting to $i/$wiki\n" );
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unset( $nonErrorLoads[$i] );
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unset( $currentLoads[$i] );
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continue;
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}
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// Perform post-connection backoff
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$threshold = isset( $this->mServers[$i]['max threads'] )
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? $this->mServers[$i]['max threads'] : 0;
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$backoff = $this->getLoadMonitor()->postConnectionBackoff( $conn, $threshold );
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// Decrement reference counter, we are finished with this connection.
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// It will be incremented for the caller later.
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if ( $wiki !== false ) {
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$this->reuseConnection( $conn );
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}
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if ( $backoff ) {
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# Post-connection overload, don't use this server for now
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$totalThreadsConnected += $backoff;
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$overloadedServers++;
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unset( $currentLoads[$i] );
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} else {
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# Return this server
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break 2;
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$laggedSlaveMode = true;
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}
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}
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# No server found yet
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$i = false;
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if ( $i === false ) {
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# pickRandom() returned false
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# This is permanent and means the configuration or the load monitor
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# wants us to return false.
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wfDebugLog( 'connect', __METHOD__ . ": pickRandom() returned false\n" );
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wfProfileOut( __METHOD__ );
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# If all servers were down, quit now
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if ( !count( $nonErrorLoads ) ) {
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wfDebugLog( 'connect', "All servers down\n" );
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break;
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return false;
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}
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# Some servers must have been overloaded
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if ( $overloadedServers == 0 ) {
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throw new MWException( __METHOD__ . ": unexpectedly found no overloaded servers" );
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}
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# Back off for a while
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# Scale the sleep time by the number of connected threads, to produce a
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# roughly constant global poll rate
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$avgThreads = $totalThreadsConnected / $overloadedServers;
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$totalElapsed += $this->sleep( $wgDBAvgStatusPoll * $avgThreads );
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} while ( $totalElapsed < $timeout );
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wfDebugLog( 'connect', __METHOD__ .
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": Using reader #$i: {$this->mServers[$i]['host']}...\n" );
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if ( $totalElapsed >= $timeout ) {
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wfDebugLog( 'connect', "All servers busy\n" );
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$this->mErrorConnection = false;
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$this->mLastError = 'All servers busy';
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$conn = $this->openConnection( $i, $wiki );
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if ( !$conn ) {
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wfDebugLog( 'connect', __METHOD__ . ": Failed connecting to $i/$wiki\n" );
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unset( $nonErrorLoads[$i] );
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unset( $currentLoads[$i] );
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continue;
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}
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// Decrement reference counter, we are finished with this connection.
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// It will be incremented for the caller later.
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if ( $wiki !== false ) {
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$this->reuseConnection( $conn );
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}
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# Return this server
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break;
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}
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# If all servers were down, quit now
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if ( !count( $nonErrorLoads ) ) {
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wfDebugLog( 'connect', "All servers down\n" );
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}
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if ( $i !== false ) {
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@ -42,24 +42,6 @@ interface LoadMonitor {
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*/
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function scaleLoads( &$loads, $group = false, $wiki = false );
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/**
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* Perform post-connection backoff.
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*
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* If the connection is in overload, this should return a backoff factor
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* which will be used to control polling time. The number of threads
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* connected is a good measure.
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*
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* If there is no overload, zero can be returned.
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*
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* A threshold thread count is given, the concrete class may compare this
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* to the running thread count. The threshold may be false, which indicates
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* that the sysadmin has not configured this feature.
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*
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* @param DatabaseBase $conn
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* @param float $threshold
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*/
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function postConnectionBackoff( $conn, $threshold );
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/**
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* Return an estimate of replication lag for each server
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*
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@ -78,9 +60,6 @@ class LoadMonitorNull implements LoadMonitor {
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function scaleLoads( &$loads, $group = false, $wiki = false ) {
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}
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function postConnectionBackoff( $conn, $threshold ) {
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}
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/**
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* @param array $serverIndexes
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* @param string $wiki
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@ -188,24 +167,4 @@ class LoadMonitorMySQL implements LoadMonitor {
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return $times;
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}
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/**
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* @param DatabaseBase|DatabaseMySQLBase $conn
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* @param int $threshold
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* @return int
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*/
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function postConnectionBackoff( $conn, $threshold ) {
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if ( !$threshold ) {
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return 0;
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}
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$status = $conn->getMysqlStatus( "Thread%" );
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if ( $status['Threads_running'] > $threshold ) {
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$server = $conn->getProperty( 'mServer' );
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wfLogDBError( "LB backoff from $server - Threads_running = {$status['Threads_running']}\n" );
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return $status['Threads_connected'];
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} else {
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return 0;
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}
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}
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}
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