Current File : /www/varak.net/wiki.varak.net/includes/libs/rdbms/TransactionProfiler.php
<?php
/**
* Transaction profiling for contention
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup Profiler
*/
namespace Wikimedia\Rdbms;
use Psr\Log\LoggerInterface;
use Psr\Log\LoggerAwareInterface;
use Psr\Log\NullLogger;
use RuntimeException;
/**
* Helper class that detects high-contention DB queries via profiling calls
*
* This class is meant to work with an IDatabase object, which manages queries
*
* @since 1.24
*/
class TransactionProfiler implements LoggerAwareInterface {
/** @var float Seconds */
protected $dbLockThreshold = 3.0;
/** @var float Seconds */
protected $eventThreshold = 0.25;
/** @var bool */
protected $silenced = false;
/** @var array transaction ID => (write start time, list of DBs involved) */
protected $dbTrxHoldingLocks = [];
/** @var array transaction ID => list of (query name, start time, end time) */
protected $dbTrxMethodTimes = [];
/** @var array */
protected $hits = [
'writes' => 0,
'queries' => 0,
'conns' => 0,
'masterConns' => 0
];
/** @var array */
protected $expect = [
'writes' => INF,
'queries' => INF,
'conns' => INF,
'masterConns' => INF,
'maxAffected' => INF,
'readQueryRows' => INF,
'readQueryTime' => INF,
'writeQueryTime' => INF
];
/** @var array */
protected $expectBy = [];
/**
* @var LoggerInterface
*/
private $logger;
public function __construct() {
$this->setLogger( new NullLogger() );
}
public function setLogger( LoggerInterface $logger ) {
$this->logger = $logger;
}
/**
* @param bool $value
* @return bool Old value
* @since 1.28
*/
public function setSilenced( $value ) {
$old = $this->silenced;
$this->silenced = $value;
return $old;
}
/**
* Set performance expectations
*
* With conflicting expectations, the most narrow ones will be used
*
* @param string $event (writes,queries,conns,mConns)
* @param int $value Maximum count of the event
* @param string $fname Caller
* @since 1.25
*/
public function setExpectation( $event, $value, $fname ) {
$this->expect[$event] = isset( $this->expect[$event] )
? min( $this->expect[$event], $value )
: $value;
if ( $this->expect[$event] == $value ) {
$this->expectBy[$event] = $fname;
}
}
/**
* Set multiple performance expectations
*
* With conflicting expectations, the most narrow ones will be used
*
* @param array $expects Map of (event => limit)
* @param string $fname
* @since 1.26
*/
public function setExpectations( array $expects, $fname ) {
foreach ( $expects as $event => $value ) {
$this->setExpectation( $event, $value, $fname );
}
}
/**
* Reset performance expectations and hit counters
*
* @since 1.25
*/
public function resetExpectations() {
foreach ( $this->hits as &$val ) {
$val = 0;
}
unset( $val );
foreach ( $this->expect as &$val ) {
$val = INF;
}
unset( $val );
$this->expectBy = [];
}
/**
* Mark a DB as having been connected to with a new handle
*
* Note that there can be multiple connections to a single DB.
*
* @param string $server DB server
* @param string $db DB name
* @param bool $isMaster
*/
public function recordConnection( $server, $db, $isMaster ) {
// Report when too many connections happen...
if ( $this->hits['conns']++ >= $this->expect['conns'] ) {
$this->reportExpectationViolated(
'conns', "[connect to $server ($db)]", $this->hits['conns'] );
}
if ( $isMaster && $this->hits['masterConns']++ >= $this->expect['masterConns'] ) {
$this->reportExpectationViolated(
'masterConns', "[connect to $server ($db)]", $this->hits['masterConns'] );
}
}
/**
* 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
* @param string $id ID string of transaction
*/
public function transactionWritingIn( $server, $db, $id ) {
$name = "{$server} ({$db}) (TRX#$id)";
if ( isset( $this->dbTrxHoldingLocks[$name] ) ) {
$this->logger->warning( "Nested transaction for '$name' - out of sync." );
}
$this->dbTrxHoldingLocks[$name] = [
'start' => microtime( true ),
'conns' => [], // all connections involved
];
$this->dbTrxMethodTimes[$name] = [];
foreach ( $this->dbTrxHoldingLocks as $name => &$info ) {
// Track all DBs in transactions for this transaction
$info['conns'][$name] = 1;
}
}
/**
* Register the name and time of a method for slow DB trx detection
*
* This assumes that all queries are synchronous (non-overlapping)
*
* @param string $query Function name or generalized SQL
* @param float $sTime Starting UNIX wall time
* @param bool $isWrite Whether this is a write query
* @param int $n Number of affected/read rows
*/
public function recordQueryCompletion( $query, $sTime, $isWrite = false, $n = 0 ) {
$eTime = microtime( true );
$elapsed = ( $eTime - $sTime );
if ( $isWrite && $n > $this->expect['maxAffected'] ) {
$this->logger->warning(
"Query affected $n row(s):\n" . $query . "\n" .
( new RuntimeException() )->getTraceAsString() );
} elseif ( !$isWrite && $n > $this->expect['readQueryRows'] ) {
$this->logger->warning(
"Query returned $n row(s):\n" . $query . "\n" .
( new RuntimeException() )->getTraceAsString() );
}
// Report when too many writes/queries happen...
if ( $this->hits['queries']++ >= $this->expect['queries'] ) {
$this->reportExpectationViolated( 'queries', $query, $this->hits['queries'] );
}
if ( $isWrite && $this->hits['writes']++ >= $this->expect['writes'] ) {
$this->reportExpectationViolated( 'writes', $query, $this->hits['writes'] );
}
// Report slow queries...
if ( !$isWrite && $elapsed > $this->expect['readQueryTime'] ) {
$this->reportExpectationViolated( 'readQueryTime', $query, $elapsed );
}
if ( $isWrite && $elapsed > $this->expect['writeQueryTime'] ) {
$this->reportExpectationViolated( 'writeQueryTime', $query, $elapsed );
}
if ( !$this->dbTrxHoldingLocks ) {
// Short-circuit
return;
} elseif ( !$isWrite && $elapsed < $this->eventThreshold ) {
// Not an important query nor slow enough
return;
}
foreach ( $this->dbTrxHoldingLocks as $name => $info ) {
$lastQuery = end( $this->dbTrxMethodTimes[$name] );
if ( $lastQuery ) {
// Additional query in the trx...
$lastEnd = $lastQuery[2];
if ( $sTime >= $lastEnd ) { // sanity check
if ( ( $sTime - $lastEnd ) > $this->eventThreshold ) {
// Add an entry representing the time spent doing non-queries
$this->dbTrxMethodTimes[$name][] = [ '...delay...', $lastEnd, $sTime ];
}
$this->dbTrxMethodTimes[$name][] = [ $query, $sTime, $eTime ];
}
} else {
// First query in the trx...
if ( $sTime >= $info['start'] ) { // sanity check
$this->dbTrxMethodTimes[$name][] = [ $query, $sTime, $eTime ];
}
}
}
}
/**
* 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
* @param string $id ID string of transaction
* @param float $writeTime Time spent in write queries
* @param int $affected Number of rows affected by writes
*/
public function transactionWritingOut( $server, $db, $id, $writeTime = 0.0, $affected = 0 ) {
$name = "{$server} ({$db}) (TRX#$id)";
if ( !isset( $this->dbTrxMethodTimes[$name] ) ) {
$this->logger->warning( "Detected no transaction for '$name' - out of sync." );
return;
}
$slow = false;
// Warn if too much time was spend writing...
if ( $writeTime > $this->expect['writeQueryTime'] ) {
$this->reportExpectationViolated(
'writeQueryTime',
"[transaction $id writes to {$server} ({$db})]",
$writeTime
);
$slow = true;
}
// Warn if too many rows were changed...
if ( $affected > $this->expect['maxAffected'] ) {
$this->reportExpectationViolated(
'maxAffected',
"[transaction $id writes to {$server} ({$db})]",
$affected
);
}
// Fill in the last non-query period...
$lastQuery = end( $this->dbTrxMethodTimes[$name] );
if ( $lastQuery ) {
$now = microtime( true );
$lastEnd = $lastQuery[2];
if ( ( $now - $lastEnd ) > $this->eventThreshold ) {
$this->dbTrxMethodTimes[$name][] = [ '...delay...', $lastEnd, $now ];
}
}
// Check for any slow queries or non-query periods...
foreach ( $this->dbTrxMethodTimes[$name] as $info ) {
$elapsed = ( $info[2] - $info[1] );
if ( $elapsed >= $this->dbLockThreshold ) {
$slow = true;
break;
}
}
if ( $slow ) {
$trace = '';
foreach ( $this->dbTrxMethodTimes[$name] as $i => $info ) {
list( $query, $sTime, $end ) = $info;
$trace .= sprintf( "%d\t%.6f\t%s\n", $i, ( $end - $sTime ), $query );
}
$this->logger->warning( "Sub-optimal transaction on DB(s) [{dbs}]: \n{trace}", [
'dbs' => implode( ', ', array_keys( $this->dbTrxHoldingLocks[$name]['conns'] ) ),
'trace' => $trace
] );
}
unset( $this->dbTrxHoldingLocks[$name] );
unset( $this->dbTrxMethodTimes[$name] );
}
/**
* @param string $expect
* @param string $query
* @param string|float|int $actual
*/
protected function reportExpectationViolated( $expect, $query, $actual ) {
if ( $this->silenced ) {
return;
}
$this->logger->warning(
"Expectation ({measure} <= {max}) by {by} not met (actual: {actual}):\n{query}\n" .
( new RuntimeException() )->getTraceAsString(),
[
'measure' => $expect,
'max' => $this->expect[$expect],
'by' => $this->expectBy[$expect],
'actual' => $actual,
'query' => $query
]
);
}
}
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