includes/profiler/TransactionProfiler.php

   1 <?php
   2 /**
   3  * Transaction profiling for contention
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Profiler
  22  * @author Aaron Schulz
  23  */
  24
  25 use Psr\Log\LoggerInterface;
  26 use Psr\Log\LoggerAwareInterface;
  27 use Psr\Log\NullLogger;
  28
  29 /**
  30  * Helper class that detects high-contention DB queries via profiling calls
  31  *
  32  * This class is meant to work with a DatabaseBase object, which manages queries
  33  *
  34  * @since 1.24
  35  */
  36 class TransactionProfiler implements LoggerAwareInterface {
  37         /** @var float Seconds */
  38         protected $dbLockThreshold = 3.0;
  39         /** @var float Seconds */
  40         protected $eventThreshold = .25;
  41
  42         /** @var array transaction ID => (write start time, list of DBs involved) */
  43         protected $dbTrxHoldingLocks = [];
  44         /** @var array transaction ID => list of (query name, start time, end time) */
  45         protected $dbTrxMethodTimes = [];
  46
  47         /** @var array */
  48         protected $hits = [
  49                 'writes'      => 0,
  50                 'queries'     => 0,
  51                 'conns'       => 0,
  52                 'masterConns' => 0
  53         ];
  54         /** @var array */
  55         protected $expect = [
  56                 'writes'         => INF,
  57                 'queries'        => INF,
  58                 'conns'          => INF,
  59                 'masterConns'    => INF,
  60                 'maxAffected'    => INF,
  61                 'readQueryTime'  => INF,
  62                 'writeQueryTime' => INF
  63         ];
  64         /** @var array */
  65         protected $expectBy = [];
  66
  67         /**
  68          * @var LoggerInterface
  69          */
  70         private $logger;
  71
  72         public function __construct() {
  73                 $this->setLogger( new NullLogger() );
  74         }
  75
  76         public function setLogger( LoggerInterface $logger ) {
  77                 $this->logger = $logger;
  78         }
  79
  80         /**
  81          * Set performance expectations
  82          *
  83          * With conflicting expectations, the most narrow ones will be used
  84          *
  85          * @param string $event (writes,queries,conns,mConns)
  86          * @param integer $value Maximum count of the event
  87          * @param string $fname Caller
  88          * @since 1.25
  89          */
  90         public function setExpectation( $event, $value, $fname ) {
  91                 $this->expect[$event] = isset( $this->expect[$event] )
  92                         ? min( $this->expect[$event], $value )
  93                         : $value;
  94                 if ( $this->expect[$event] == $value ) {
  95                         $this->expectBy[$event] = $fname;
  96                 }
  97         }
  98
  99         /**
 100          * Set multiple performance expectations
 101          *
 102          * With conflicting expectations, the most narrow ones will be used
 103          *
 104          * @param array $expects Map of (event => limit)
 105          * @param $fname
 106          * @since 1.26
 107          */
 108         public function setExpectations( array $expects, $fname ) {
 109                 foreach ( $expects as $event => $value ) {
 110                         $this->setExpectation( $event, $value, $fname );
 111                 }
 112         }
 113
 114         /**
 115          * Reset performance expectations and hit counters
 116          *
 117          * @since 1.25
 118          */
 119         public function resetExpectations() {
 120                 foreach ( $this->hits as &$val ) {
 121                         $val = 0;
 122                 }
 123                 unset( $val );
 124                 foreach ( $this->expect as &$val ) {
 125                         $val = INF;
 126                 }
 127                 unset( $val );
 128                 $this->expectBy = [];
 129         }
 130
 131         /**
 132          * Mark a DB as having been connected to with a new handle
 133          *
 134          * Note that there can be multiple connections to a single DB.
 135          *
 136          * @param string $server DB server
 137          * @param string $db DB name
 138          * @param bool $isMaster
 139          */
 140         public function recordConnection( $server, $db, $isMaster ) {
 141                 // Report when too many connections happen...
 142                 if ( $this->hits['conns']++ == $this->expect['conns'] ) {
 143                         $this->reportExpectationViolated( 'conns', "[connect to $server ($db)]" );
 144                 }
 145                 if ( $isMaster && $this->hits['masterConns']++ == $this->expect['masterConns'] ) {
 146                         $this->reportExpectationViolated( 'masterConns', "[connect to $server ($db)]" );
 147                 }
 148         }
 149
 150         /**
 151          * Mark a DB as in a transaction with one or more writes pending
 152          *
 153          * Note that there can be multiple connections to a single DB.
 154          *
 155          * @param string $server DB server
 156          * @param string $db DB name
 157          * @param string $id ID string of transaction
 158          */
 159         public function transactionWritingIn( $server, $db, $id ) {
 160                 $name = "{$server} ({$db}) (TRX#$id)";
 161                 if ( isset( $this->dbTrxHoldingLocks[$name] ) ) {
 162                         $this->logger->info( "Nested transaction for '$name' - out of sync." );
 163                 }
 164                 $this->dbTrxHoldingLocks[$name] = [
 165                         'start' => microtime( true ),
 166                         'conns' => [], // all connections involved
 167                 ];
 168                 $this->dbTrxMethodTimes[$name] = [];
 169
 170                 foreach ( $this->dbTrxHoldingLocks as $name => &$info ) {
 171                         // Track all DBs in transactions for this transaction
 172                         $info['conns'][$name] = 1;
 173                 }
 174         }
 175
 176         /**
 177          * Register the name and time of a method for slow DB trx detection
 178          *
 179          * This assumes that all queries are synchronous (non-overlapping)
 180          *
 181          * @param string $query Function name or generalized SQL
 182          * @param float $sTime Starting UNIX wall time
 183          * @param bool $isWrite Whether this is a write query
 184          * @param integer $n Number of affected rows
 185          */
 186         public function recordQueryCompletion( $query, $sTime, $isWrite = false, $n = 0 ) {
 187                 $eTime = microtime( true );
 188                 $elapsed = ( $eTime - $sTime );
 189
 190                 if ( $isWrite && $n > $this->expect['maxAffected'] ) {
 191                         $this->logger->info( "Query affected $n row(s):\n" . $query . "\n" .
 192                                 wfBacktrace( true ) );
 193                 }
 194
 195                 // Report when too many writes/queries happen...
 196                 if ( $this->hits['queries']++ == $this->expect['queries'] ) {
 197                         $this->reportExpectationViolated( 'queries', $query );
 198                 }
 199                 if ( $isWrite && $this->hits['writes']++ == $this->expect['writes'] ) {
 200                         $this->reportExpectationViolated( 'writes', $query );
 201                 }
 202                 // Report slow queries...
 203                 if ( !$isWrite && $elapsed > $this->expect['readQueryTime'] ) {
 204                         $this->reportExpectationViolated( 'readQueryTime', $query, $elapsed );
 205                 }
 206                 if ( $isWrite && $elapsed > $this->expect['writeQueryTime'] ) {
 207                         $this->reportExpectationViolated( 'writeQueryTime', $query, $elapsed );
 208                 }
 209
 210                 if ( !$this->dbTrxHoldingLocks ) {
 211                         // Short-circuit
 212                         return;
 213                 } elseif ( !$isWrite && $elapsed < $this->eventThreshold ) {
 214                         // Not an important query nor slow enough
 215                         return;
 216                 }
 217
 218                 foreach ( $this->dbTrxHoldingLocks as $name => $info ) {
 219                         $lastQuery = end( $this->dbTrxMethodTimes[$name] );
 220                         if ( $lastQuery ) {
 221                                 // Additional query in the trx...
 222                                 $lastEnd = $lastQuery[2];
 223                                 if ( $sTime >= $lastEnd ) { // sanity check
 224                                         if ( ( $sTime - $lastEnd ) > $this->eventThreshold ) {
 225                                                 // Add an entry representing the time spent doing non-queries
 226                                                 $this->dbTrxMethodTimes[$name][] = [ '...delay...', $lastEnd, $sTime ];
 227                                         }
 228                                         $this->dbTrxMethodTimes[$name][] = [ $query, $sTime, $eTime ];
 229                                 }
 230                         } else {
 231                                 // First query in the trx...
 232                                 if ( $sTime >= $info['start'] ) { // sanity check
 233                                         $this->dbTrxMethodTimes[$name][] = [ $query, $sTime, $eTime ];
 234                                 }
 235                         }
 236                 }
 237         }
 238
 239         /**
 240          * Mark a DB as no longer in a transaction
 241          *
 242          * This will check if locks are possibly held for longer than
 243          * needed and log any affected transactions to a special DB log.
 244          * Note that there can be multiple connections to a single DB.
 245          *
 246          * @param string $server DB server
 247          * @param string $db DB name
 248          * @param string $id ID string of transaction
 249          * @param float $writeTime Time spent in write queries
 250          */
 251         public function transactionWritingOut( $server, $db, $id, $writeTime = 0.0 ) {
 252                 $name = "{$server} ({$db}) (TRX#$id)";
 253                 if ( !isset( $this->dbTrxMethodTimes[$name] ) ) {
 254                         $this->logger->info( "Detected no transaction for '$name' - out of sync." );
 255                         return;
 256                 }
 257
 258                 $slow = false;
 259
 260                 // Warn if too much time was spend writing...
 261                 if ( $writeTime > $this->expect['writeQueryTime'] ) {
 262                         $this->reportExpectationViolated(
 263                                 'writeQueryTime',
 264                                 "[transaction $id writes to {$server} ({$db})]",
 265                                 $writeTime
 266                         );
 267                         $slow = true;
 268                 }
 269                 // Fill in the last non-query period...
 270                 $lastQuery = end( $this->dbTrxMethodTimes[$name] );
 271                 if ( $lastQuery ) {
 272                         $now = microtime( true );
 273                         $lastEnd = $lastQuery[2];
 274                         if ( ( $now - $lastEnd ) > $this->eventThreshold ) {
 275                                 $this->dbTrxMethodTimes[$name][] = [ '...delay...', $lastEnd, $now ];
 276                         }
 277                 }
 278                 // Check for any slow queries or non-query periods...
 279                 foreach ( $this->dbTrxMethodTimes[$name] as $info ) {
 280                         $elapsed = ( $info[2] - $info[1] );
 281                         if ( $elapsed >= $this->dbLockThreshold ) {
 282                                 $slow = true;
 283                                 break;
 284                         }
 285                 }
 286                 if ( $slow ) {
 287                         $dbs = implode( ', ', array_keys( $this->dbTrxHoldingLocks[$name]['conns'] ) );
 288                         $msg = "Sub-optimal transaction on DB(s) [{$dbs}]:\n";
 289                         foreach ( $this->dbTrxMethodTimes[$name] as $i => $info ) {
 290                                 list( $query, $sTime, $end ) = $info;
 291                                 $msg .= sprintf( "%d\t%.6f\t%s\n", $i, ( $end - $sTime ), $query );
 292                         }
 293                         $this->logger->info( $msg );
 294                 }
 295                 unset( $this->dbTrxHoldingLocks[$name] );
 296                 unset( $this->dbTrxMethodTimes[$name] );
 297         }
 298
 299         /**
 300          * @param string $expect
 301          * @param string $query
 302          * @param string|float|int $actual [optional]
 303          */
 304         protected function reportExpectationViolated( $expect, $query, $actual = null ) {
 305                 $n = $this->expect[$expect];
 306                 $by = $this->expectBy[$expect];
 307                 $actual = ( $actual !== null ) ? " (actual: $actual)" : "";
 308
 309                 $this->logger->info(
 310                         "Expectation ($expect <= $n) by $by not met$actual:\n$query\n" .
 311                         wfBacktrace( true )
 312                 );
 313         }
 314 }