includes/libs/rdbms/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 an IDatabase 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         /** @var bool */
  42         protected $silenced = false;
  43
  44         /** @var array transaction ID => (write start time, list of DBs involved) */
  45         protected $dbTrxHoldingLocks = [];
  46         /** @var array transaction ID => list of (query name, start time, end time) */
  47         protected $dbTrxMethodTimes = [];
  48
  49         /** @var array */
  50         protected $hits = [
  51                 'writes'      => 0,
  52                 'queries'     => 0,
  53                 'conns'       => 0,
  54                 'masterConns' => 0
  55         ];
  56         /** @var array */
  57         protected $expect = [
  58                 'writes'         => INF,
  59                 'queries'        => INF,
  60                 'conns'          => INF,
  61                 'masterConns'    => INF,
  62                 'maxAffected'    => INF,
  63                 'readQueryTime'  => INF,
  64                 'writeQueryTime' => INF
  65         ];
  66         /** @var array */
  67         protected $expectBy = [];
  68
  69         /**
  70          * @var LoggerInterface
  71          */
  72         private $logger;
  73
  74         public function __construct() {
  75                 $this->setLogger( new NullLogger() );
  76         }
  77
  78         public function setLogger( LoggerInterface $logger ) {
  79                 $this->logger = $logger;
  80         }
  81
  82         /**
  83          * @param bool $value New value
  84          * @return bool Old value
  85          * @since 1.28
  86          */
  87         public function setSilenced( $value ) {
  88                 $old = $this->silenced;
  89                 $this->silenced = $value;
  90
  91                 return $old;
  92         }
  93
  94         /**
  95          * Set performance expectations
  96          *
  97          * With conflicting expectations, the most narrow ones will be used
  98          *
  99          * @param string $event (writes,queries,conns,mConns)
 100          * @param integer $value Maximum count of the event
 101          * @param string $fname Caller
 102          * @since 1.25
 103          */
 104         public function setExpectation( $event, $value, $fname ) {
 105                 $this->expect[$event] = isset( $this->expect[$event] )
 106                         ? min( $this->expect[$event], $value )
 107                         : $value;
 108                 if ( $this->expect[$event] == $value ) {
 109                         $this->expectBy[$event] = $fname;
 110                 }
 111         }
 112
 113         /**
 114          * Set multiple performance expectations
 115          *
 116          * With conflicting expectations, the most narrow ones will be used
 117          *
 118          * @param array $expects Map of (event => limit)
 119          * @param $fname
 120          * @since 1.26
 121          */
 122         public function setExpectations( array $expects, $fname ) {
 123                 foreach ( $expects as $event => $value ) {
 124                         $this->setExpectation( $event, $value, $fname );
 125                 }
 126         }
 127
 128         /**
 129          * Reset performance expectations and hit counters
 130          *
 131          * @since 1.25
 132          */
 133         public function resetExpectations() {
 134                 foreach ( $this->hits as &$val ) {
 135                         $val = 0;
 136                 }
 137                 unset( $val );
 138                 foreach ( $this->expect as &$val ) {
 139                         $val = INF;
 140                 }
 141                 unset( $val );
 142                 $this->expectBy = [];
 143         }
 144
 145         /**
 146          * Mark a DB as having been connected to with a new handle
 147          *
 148          * Note that there can be multiple connections to a single DB.
 149          *
 150          * @param string $server DB server
 151          * @param string $db DB name
 152          * @param bool $isMaster
 153          */
 154         public function recordConnection( $server, $db, $isMaster ) {
 155                 // Report when too many connections happen...
 156                 if ( $this->hits['conns']++ == $this->expect['conns'] ) {
 157                         $this->reportExpectationViolated( 'conns', "[connect to $server ($db)]" );
 158                 }
 159                 if ( $isMaster && $this->hits['masterConns']++ == $this->expect['masterConns'] ) {
 160                         $this->reportExpectationViolated( 'masterConns', "[connect to $server ($db)]" );
 161                 }
 162         }
 163
 164         /**
 165          * Mark a DB as in a transaction with one or more writes pending
 166          *
 167          * Note that there can be multiple connections to a single DB.
 168          *
 169          * @param string $server DB server
 170          * @param string $db DB name
 171          * @param string $id ID string of transaction
 172          */
 173         public function transactionWritingIn( $server, $db, $id ) {
 174                 $name = "{$server} ({$db}) (TRX#$id)";
 175                 if ( isset( $this->dbTrxHoldingLocks[$name] ) ) {
 176                         $this->logger->info( "Nested transaction for '$name' - out of sync." );
 177                 }
 178                 $this->dbTrxHoldingLocks[$name] = [
 179                         'start' => microtime( true ),
 180                         'conns' => [], // all connections involved
 181                 ];
 182                 $this->dbTrxMethodTimes[$name] = [];
 183
 184                 foreach ( $this->dbTrxHoldingLocks as $name => &$info ) {
 185                         // Track all DBs in transactions for this transaction
 186                         $info['conns'][$name] = 1;
 187                 }
 188         }
 189
 190         /**
 191          * Register the name and time of a method for slow DB trx detection
 192          *
 193          * This assumes that all queries are synchronous (non-overlapping)
 194          *
 195          * @param string $query Function name or generalized SQL
 196          * @param float $sTime Starting UNIX wall time
 197          * @param bool $isWrite Whether this is a write query
 198          * @param integer $n Number of affected rows
 199          */
 200         public function recordQueryCompletion( $query, $sTime, $isWrite = false, $n = 0 ) {
 201                 $eTime = microtime( true );
 202                 $elapsed = ( $eTime - $sTime );
 203
 204                 if ( $isWrite && $n > $this->expect['maxAffected'] ) {
 205                         $this->logger->info(
 206                                 "Query affected $n row(s):\n" . $query . "\n" .
 207                                 ( new RuntimeException() )->getTraceAsString() );
 208                 }
 209
 210                 // Report when too many writes/queries happen...
 211                 if ( $this->hits['queries']++ == $this->expect['queries'] ) {
 212                         $this->reportExpectationViolated( 'queries', $query );
 213                 }
 214                 if ( $isWrite && $this->hits['writes']++ == $this->expect['writes'] ) {
 215                         $this->reportExpectationViolated( 'writes', $query );
 216                 }
 217                 // Report slow queries...
 218                 if ( !$isWrite && $elapsed > $this->expect['readQueryTime'] ) {
 219                         $this->reportExpectationViolated( 'readQueryTime', $query, $elapsed );
 220                 }
 221                 if ( $isWrite && $elapsed > $this->expect['writeQueryTime'] ) {
 222                         $this->reportExpectationViolated( 'writeQueryTime', $query, $elapsed );
 223                 }
 224
 225                 if ( !$this->dbTrxHoldingLocks ) {
 226                         // Short-circuit
 227                         return;
 228                 } elseif ( !$isWrite && $elapsed < $this->eventThreshold ) {
 229                         // Not an important query nor slow enough
 230                         return;
 231                 }
 232
 233                 foreach ( $this->dbTrxHoldingLocks as $name => $info ) {
 234                         $lastQuery = end( $this->dbTrxMethodTimes[$name] );
 235                         if ( $lastQuery ) {
 236                                 // Additional query in the trx...
 237                                 $lastEnd = $lastQuery[2];
 238                                 if ( $sTime >= $lastEnd ) { // sanity check
 239                                         if ( ( $sTime - $lastEnd ) > $this->eventThreshold ) {
 240                                                 // Add an entry representing the time spent doing non-queries
 241                                                 $this->dbTrxMethodTimes[$name][] = [ '...delay...', $lastEnd, $sTime ];
 242                                         }
 243                                         $this->dbTrxMethodTimes[$name][] = [ $query, $sTime, $eTime ];
 244                                 }
 245                         } else {
 246                                 // First query in the trx...
 247                                 if ( $sTime >= $info['start'] ) { // sanity check
 248                                         $this->dbTrxMethodTimes[$name][] = [ $query, $sTime, $eTime ];
 249                                 }
 250                         }
 251                 }
 252         }
 253
 254         /**
 255          * Mark a DB as no longer in a transaction
 256          *
 257          * This will check if locks are possibly held for longer than
 258          * needed and log any affected transactions to a special DB log.
 259          * Note that there can be multiple connections to a single DB.
 260          *
 261          * @param string $server DB server
 262          * @param string $db DB name
 263          * @param string $id ID string of transaction
 264          * @param float $writeTime Time spent in write queries
 265          */
 266         public function transactionWritingOut( $server, $db, $id, $writeTime = 0.0 ) {
 267                 $name = "{$server} ({$db}) (TRX#$id)";
 268                 if ( !isset( $this->dbTrxMethodTimes[$name] ) ) {
 269                         $this->logger->info( "Detected no transaction for '$name' - out of sync." );
 270                         return;
 271                 }
 272
 273                 $slow = false;
 274
 275                 // Warn if too much time was spend writing...
 276                 if ( $writeTime > $this->expect['writeQueryTime'] ) {
 277                         $this->reportExpectationViolated(
 278                                 'writeQueryTime',
 279                                 "[transaction $id writes to {$server} ({$db})]",
 280                                 $writeTime
 281                         );
 282                         $slow = true;
 283                 }
 284                 // Fill in the last non-query period...
 285                 $lastQuery = end( $this->dbTrxMethodTimes[$name] );
 286                 if ( $lastQuery ) {
 287                         $now = microtime( true );
 288                         $lastEnd = $lastQuery[2];
 289                         if ( ( $now - $lastEnd ) > $this->eventThreshold ) {
 290                                 $this->dbTrxMethodTimes[$name][] = [ '...delay...', $lastEnd, $now ];
 291                         }
 292                 }
 293                 // Check for any slow queries or non-query periods...
 294                 foreach ( $this->dbTrxMethodTimes[$name] as $info ) {
 295                         $elapsed = ( $info[2] - $info[1] );
 296                         if ( $elapsed >= $this->dbLockThreshold ) {
 297                                 $slow = true;
 298                                 break;
 299                         }
 300                 }
 301                 if ( $slow ) {
 302                         $trace = '';
 303                         foreach ( $this->dbTrxMethodTimes[$name] as $i => $info ) {
 304                                 list( $query, $sTime, $end ) = $info;
 305                                 $trace .= sprintf( "%d\t%.6f\t%s\n", $i, ( $end - $sTime ), $query );
 306                         }
 307                         $this->logger->info( "Sub-optimal transaction on DB(s) [{dbs}]: \n{trace}", [
 308                                 'dbs' => implode( ', ', array_keys( $this->dbTrxHoldingLocks[$name]['conns'] ) ),
 309                                 'trace' => $trace
 310                         ] );
 311                 }
 312                 unset( $this->dbTrxHoldingLocks[$name] );
 313                 unset( $this->dbTrxMethodTimes[$name] );
 314         }
 315
 316         /**
 317          * @param string $expect
 318          * @param string $query
 319          * @param string|float|int $actual [optional]
 320          */
 321         protected function reportExpectationViolated( $expect, $query, $actual = null ) {
 322                 if ( $this->silenced ) {
 323                         return;
 324                 }
 325
 326                 $n = $this->expect[$expect];
 327                 $by = $this->expectBy[$expect];
 328                 $actual = ( $actual !== null ) ? " (actual: $actual)" : "";
 329
 330                 $this->logger->info(
 331                         "Expectation ($expect <= $n) by $by not met$actual:\n$query\n" .
 332                         ( new RuntimeException() )->getTraceAsString()
 333                 );
 334         }
 335 }