jenkins-bot has submitted this change and it was merged.
Change subject: profiler: log slow methods that worsen DB locks in transactions
......................................................................
profiler: log slow methods that worsen DB locks in transactions
Change-Id: I1aa13c29837fa655c13ef324d02cd1be1739edea
---
M includes/db/Database.php
M includes/profiler/Profiler.php
M includes/profiler/ProfilerSimple.php
M includes/profiler/ProfilerSimpleTrace.php
M includes/profiler/ProfilerStub.php
5 files changed, 108 insertions(+), 11 deletions(-)
Approvals:
Tim Starling: Looks good to me, approved
jenkins-bot: Verified
diff --git a/includes/db/Database.php b/includes/db/Database.php
index 04f1f97..f9f4d5d 100644
--- a/includes/db/Database.php
+++ b/includes/db/Database.php
@@ -938,6 +938,7 @@
# Keep track of whether the transaction has write queries
pending
if ( $this->mTrxLevel && !$this->mTrxDoneWrites &&
$this->isWriteQuery( $sql ) ) {
$this->mTrxDoneWrites = true;
+ Profiler::instance()->transactionWritingIn(
$this->mServer, $this->mDBname );
}
if ( $this->debug() ) {
@@ -3172,6 +3173,9 @@
$this->runOnTransactionPreCommitCallbacks();
$this->doCommit( $fname );
+ if ( $this->mTrxDoneWrites ) {
+ Profiler::instance()->transactionWritingOut(
$this->mServer, $this->mDBname );
+ }
$this->runOnTransactionIdleCallbacks();
}
@@ -3221,6 +3225,9 @@
$this->runOnTransactionPreCommitCallbacks();
$this->doCommit( $fname );
+ if ( $this->mTrxDoneWrites ) {
+ Profiler::instance()->transactionWritingOut(
$this->mServer, $this->mDBname );
+ }
$this->runOnTransactionIdleCallbacks();
}
@@ -3252,6 +3259,9 @@
$this->doRollback( $fname );
$this->mTrxIdleCallbacks = array(); // cancel
$this->mTrxPreCommitCallbacks = array(); // cancel
+ if ( $this->mTrxDoneWrites ) {
+ Profiler::instance()->transactionWritingOut(
$this->mServer, $this->mDBname );
+ }
}
/**
diff --git a/includes/profiler/Profiler.php b/includes/profiler/Profiler.php
index 7ca4c2d..0ef12ec 100644
--- a/includes/profiler/Profiler.php
+++ b/includes/profiler/Profiler.php
@@ -100,6 +100,12 @@
protected $mTimeMetric = 'wall';
protected $mProfileID = false, $mCollateDone = false, $mTemplated =
false;
+ protected $mDBLockThreshold = 5.0; // float; seconds
+ /** @var Array DB/server name => (active trx count,timestamp) */
+ protected $mDBTrxHoldingLocks = array();
+ /** @var Array DB/server name => list of (method, elapsed time) */
+ protected $mDBTrxMethodTimes = array();
+
/** @var Profiler */
public static $__instance = null; // do not call this outside Profiler
and ProfileSection
@@ -223,20 +229,19 @@
if ( !$bit ) {
$this->debug( "Profiling error, !\$bit:
$functionname\n" );
} else {
- //if( $wgDebugProfiling ) {
- if ( $functionname == 'close' ) {
- $message = "Profile section ended by
close(): {$bit[0]}";
- $this->debug( "$message\n" );
- $this->mStack[] = array( $message, 0,
0.0, 0, 0.0, 0 );
- } elseif ( $bit[0] != $functionname ) {
- $message = "Profiling error:
in({$bit[0]}), out($functionname)";
- $this->debug( "$message\n" );
- $this->mStack[] = array( $message, 0,
0.0, 0, 0.0, 0 );
- }
- //}
+ if ( $functionname == 'close' ) {
+ $message = "Profile section ended by close():
{$bit[0]}";
+ $this->debug( "$message\n" );
+ $this->mStack[] = array( $message, 0, 0.0, 0,
0.0, 0 );
+ } elseif ( $bit[0] != $functionname ) {
+ $message = "Profiling error: in({$bit[0]}),
out($functionname)";
+ $this->debug( "$message\n" );
+ $this->mStack[] = array( $message, 0, 0.0, 0,
0.0, 0 );
+ }
$bit[] = $time;
$bit[] = $memory;
$this->mStack[] = $bit;
+ $this->updateTrxProfiling( $functionname, $time );
}
}
@@ -250,6 +255,83 @@
}
/**
+ * Mark a DB as in a transaction with one or more writes pending
+ *
+ * Note that there can be multiple connections to a single DB.
+ *
+ * @param string $server DB server
+ * @param string $db DB name
+ */
+ public function transactionWritingIn( $server, $db ) {
+ $name = "{$server} ({$db})";
+ if ( isset( $this->mDBTrxHoldingLocks[$name] ) ) {
+ ++$this->mDBTrxHoldingLocks[$name]['refs'];
+ } else {
+ $this->mDBTrxHoldingLocks[$name] = array( 'refs' => 1,
'start' => microtime( true ) );
+ $this->mDBTrxMethodTimes[$name] = array();
+ }
+ }
+
+ /**
+ * Register the name and time of a method for slow DB trx detection
+ *
+ * @param string $method Function name
+ * @param float $realtime Wal time ellapsed
+ */
+ protected function updateTrxProfiling( $method, $realtime ) {
+ if ( !$this->mDBTrxHoldingLocks ) {
+ return; // short-circuit
+ // @TODO: hardcoded check is a tad janky (what about FOR
UPDATE?)
+ } elseif ( !preg_match( '/^query-m: (?!SELECT)/', $method )
+ && $realtime < $this->mDBLockThreshold )
+ {
+ return; // not a DB master query nor slow enough
+ }
+ $now = microtime( true );
+ foreach ( $this->mDBTrxHoldingLocks as $name => $info ) {
+ // Hacky check to exclude entries from before the first
TRX write
+ if ( ( $now - $realtime ) >= $info['start'] ) {
+ $this->mDBTrxMethodTimes[$name][] = array(
$method, $realtime );
+ }
+ }
+ }
+
+ /**
+ * Mark a DB as no longer in a transaction
+ *
+ * This will check if locks are possibly held for longer than
+ * needed and log any affected transactions to a special DB log.
+ * Note that there can be multiple connections to a single DB.
+ *
+ * @param string $server DB server
+ * @param string $db DB name
+ */
+ public function transactionWritingOut( $server, $db ) {
+ $name = "{$server} ({$db})";
+ if ( --$this->mDBTrxHoldingLocks[$name]['refs'] <= 0 ) {
+ $slow = false;
+ foreach ( $this->mDBTrxMethodTimes[$name] as $info ) {
+ list( $method, $realtime ) = $info;
+ if ( $realtime >= $this->mDBLockThreshold ) {
+ $slow = true;
+ break;
+ }
+ }
+ if ( $slow ) {
+ $dbs = implode( ', ', array_keys(
$this->mDBTrxHoldingLocks ) );
+ $msg = "Sub-optimal transaction on DB(s)
{$dbs}:\n";
+ foreach ( $this->mDBTrxMethodTimes[$name] as $i
=> $info ) {
+ list( $method, $realtime ) = $info;
+ $msg .= sprintf( "%d\t%.6f\t%s\n", $i,
$realtime, $method );
+ }
+ wfDebugLog( 'DBPerfomance', $msg );
+ }
+ unset( $this->mDBTrxHoldingLocks[$name] );
+ unset( $this->mDBTrxMethodTimes[$name] );
+ }
+ }
+
+ /**
* Mark this call as templated or not
*
* @param $t Boolean
diff --git a/includes/profiler/ProfilerSimple.php
b/includes/profiler/ProfilerSimple.php
index b59c528..805c60f 100644
--- a/includes/profiler/ProfilerSimple.php
+++ b/includes/profiler/ProfilerSimple.php
@@ -101,6 +101,7 @@
$entry['real_sq'] += $elapsedreal * $elapsedreal;
$entry['count']++;
+ $this->updateTrxProfiling( $functionname, $elapsedreal
);
}
}
diff --git a/includes/profiler/ProfilerSimpleTrace.php
b/includes/profiler/ProfilerSimpleTrace.php
index d44dfe1..5588d1e 100644
--- a/includes/profiler/ProfilerSimpleTrace.php
+++ b/includes/profiler/ProfilerSimpleTrace.php
@@ -59,6 +59,8 @@
$elapsedreal = $this->getTime() - $ortime;
$this->trace .= sprintf( "%03.6f %6.1f", $elapsedreal,
$this->memoryDiff() ) .
str_repeat( " ", count(
$this->mWorkStack ) + 1 ) . " < " . $functionname . "\n";
+
+ $this->updateTrxProfiling( $functionname, $elapsedreal
);
}
}
diff --git a/includes/profiler/ProfilerStub.php
b/includes/profiler/ProfilerStub.php
index c0eb0fb..3697f35 100644
--- a/includes/profiler/ProfilerStub.php
+++ b/includes/profiler/ProfilerStub.php
@@ -39,4 +39,6 @@
public function close() {}
public function logData() {}
public function getCurrentSection() { return ''; }
+ public function transactionWritingIn( $server, $db ) {}
+ public function transactionWritingOut( $server, $db ) {}
}
--
To view, visit https://gerrit.wikimedia.org/r/70923
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: merged
Gerrit-Change-Id: I1aa13c29837fa655c13ef324d02cd1be1739edea
Gerrit-PatchSet: 7
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Aaron Schulz <[email protected]>
Gerrit-Reviewer: Aaron Schulz <[email protected]>
Gerrit-Reviewer: Demon <[email protected]>
Gerrit-Reviewer: Tim Starling <[email protected]>
Gerrit-Reviewer: jenkins-bot
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