includes/SecondaryDBDataUpdate.php

   1 <?php
   2 /**
   3  * See docs/deferred.txt
   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  * Abstract base class for update jobs that put some secondary data extracted
  21  * from article content into the database.
  22  */
  23 abstract class SecondaryDBDataUpdate extends SecondaryDataUpdate {
  24
  25         /**@{{
  26          * @private
  27          */
  28         var $mDb,            //!< Database connection reference
  29                 $mOptions,       //!< SELECT options to be used (array)
  30                 $mHasTransaction;//!< bool whether a transaction is open on this object (internal use only!)
  31         /**@}}*/
  32
  33         /**
  34          * Constructor
  35         **/
  36         public function __construct( ) {
  37                 global $wgAntiLockFlags;
  38
  39                 parent::__construct( );
  40
  41                 if ( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) {
  42                         $this->mOptions = array();
  43                 } else {
  44                         $this->mOptions = array( 'FOR UPDATE' );
  45                 }
  46                 $this->mDb = wfGetDB( DB_MASTER );
  47                 $this->mHasTransaction = false;
  48         }
  49
  50         /**
  51          * Begin a database transaction.
  52          *
  53          * Because nested transactions are not supportred by the Database class, this implementation
  54          * checked Database::trxLevel() and only opens a transaction if none is yet active.
  55          */
  56         public function beginTransaction() {
  57                 // NOTE: nested transactions are not supported, only start a transaction if none is open
  58                 if ( $this->mDb->trxLevel() === 0 ) {
  59                         $this->mDb->begin( get_class( $this ) . '::beginTransaction'  );
  60                         $this->mHasTransaction = true;
  61                 }
  62         }
  63
  64         /**
  65          * Commit the database transaction started via beginTransaction (if any).
  66          */
  67         public function commitTransaction() {
  68                 if ( $this->mHasTransaction ) {
  69                         $this->mDb->commit( get_class( $this ) . '::commitTransaction' );
  70                 }
  71         }
  72
  73         /**
  74          * Abort the database transaction started via beginTransaction (if any).
  75          */
  76         public function abortTransaction() {
  77                 if ( $this->mHasTransaction ) {
  78                         $this->mDb->rollback( get_class( $this ) . '::abortTransaction' );
  79                 }
  80         }
  81
  82         /**
  83          * Invalidate the cache of a list of pages from a single namespace.
  84          * This is intended for use by subclasses.
  85          *
  86          * @param $namespace Integer
  87          * @param $dbkeys Array
  88          */
  89         protected function invalidatePages( $namespace, $dbkeys ) {
  90                 if ( !count( $dbkeys ) ) {
  91                         return;
  92                 }
  93
  94                 /**
  95                  * Determine which pages need to be updated
  96                  * This is necessary to prevent the job queue from smashing the DB with
  97                  * large numbers of concurrent invalidations of the same page
  98                  */
  99                 $now = $this->mDb->timestamp();
 100                 $ids = array();
 101                 $res = $this->mDb->select( 'page', array( 'page_id' ),
 102                         array(
 103                                 'page_namespace' => $namespace,
 104                                 'page_title IN (' . $this->mDb->makeList( $dbkeys ) . ')',
 105                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 106                         ), __METHOD__
 107                 );
 108                 foreach ( $res as $row ) {
 109                         $ids[] = $row->page_id;
 110                 }
 111                 if ( !count( $ids ) ) {
 112                         return;
 113                 }
 114
 115                 /**
 116                  * Do the update
 117                  * We still need the page_touched condition, in case the row has changed since
 118                  * the non-locking select above.
 119                  */
 120                 $this->mDb->update( 'page', array( 'page_touched' => $now ),
 121                         array(
 122                                 'page_id IN (' . $this->mDb->makeList( $ids ) . ')',
 123                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 124                         ), __METHOD__
 125                 );
 126         }
 127
 128 }