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  * @since WD.1
  24  */
  25 abstract class SecondaryDBDataUpdate extends SecondaryDataUpdate {
  26
  27         /**@{{
  28          * @private
  29          */
  30         var $mDb,            //!< Database connection reference
  31                 $mOptions,       //!< SELECT options to be used (array)
  32                 $mHasTransaction;//!< bool whether a transaction is open on this object (internal use only!)
  33         /**@}}*/
  34
  35         /**
  36          * Constructor
  37         **/
  38         public function __construct( ) {
  39                 global $wgAntiLockFlags;
  40
  41                 parent::__construct( );
  42
  43                 if ( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) {
  44                         $this->mOptions = array();
  45                 } else {
  46                         $this->mOptions = array( 'FOR UPDATE' );
  47                 }
  48                 $this->mDb = wfGetDB( DB_MASTER );
  49                 $this->mHasTransaction = false;
  50         }
  51
  52         /**
  53          * Begin a database transaction.
  54          *
  55          * Because nested transactions are not supportred by the Database class, this implementation
  56          * checked Database::trxLevel() and only opens a transaction if none is yet active.
  57          *
  58          * @since WD.1
  59          */
  60         public function beginTransaction() {
  61                 // NOTE: nested transactions are not supported, only start a transaction if none is open
  62                 if ( $this->mDb->trxLevel() === 0 ) {
  63                         $this->mDb->begin( get_class( $this ) . '::beginTransaction'  );
  64                         $this->mHasTransaction = true;
  65                 }
  66         }
  67
  68         /**
  69          * Commit the database transaction started via beginTransaction (if any).
  70          *
  71          * @since WD.1
  72          */
  73         public function commitTransaction() {
  74                 if ( $this->mHasTransaction ) {
  75                         $this->mDb->commit( get_class( $this ) . '::commitTransaction' );
  76                 }
  77         }
  78
  79         /**
  80          * Abort the database transaction started via beginTransaction (if any).
  81          *
  82          * @since WD.1
  83          */
  84         public function abortTransaction() {
  85                 if ( $this->mHasTransaction ) {
  86                         $this->mDb->rollback( get_class( $this ) . '::abortTransaction' );
  87                 }
  88         }
  89
  90         /**
  91          * Invalidate the cache of a list of pages from a single namespace.
  92          * This is intended for use by subclasses.
  93          *
  94          * @since WD.1
  95          *
  96          * @param $namespace Integer
  97          * @param $dbkeys Array
  98          */
  99         protected function invalidatePages( $namespace, $dbkeys ) {
 100                 if ( !count( $dbkeys ) ) {
 101                         return;
 102                 }
 103
 104                 /**
 105                  * Determine which pages need to be updated
 106                  * This is necessary to prevent the job queue from smashing the DB with
 107                  * large numbers of concurrent invalidations of the same page
 108                  */
 109                 $now = $this->mDb->timestamp();
 110                 $ids = array();
 111                 $res = $this->mDb->select( 'page', array( 'page_id' ),
 112                         array(
 113                                 'page_namespace' => $namespace,
 114                                 'page_title IN (' . $this->mDb->makeList( $dbkeys ) . ')',
 115                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 116                         ), __METHOD__
 117                 );
 118                 foreach ( $res as $row ) {
 119                         $ids[] = $row->page_id;
 120                 }
 121                 if ( !count( $ids ) ) {
 122                         return;
 123                 }
 124
 125                 /**
 126                  * Do the update
 127                  * We still need the page_touched condition, in case the row has changed since
 128                  * the non-locking select above.
 129                  */
 130                 $this->mDb->update( 'page', array( 'page_touched' => $now ),
 131                         array(
 132                                 'page_id IN (' . $this->mDb->makeList( $ids ) . ')',
 133                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 134                         ), __METHOD__
 135                 );
 136         }
 137
 138 }