3 * Run a database query in batches and wait for replica DBs. This is used on large
4 * wikis to prevent replication lag from going through the roof when executing
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 * http://www.gnu.org/copyleft/gpl.html
23 * @ingroup Maintenance
26 require_once __DIR__
. '/Maintenance.php';
29 * Maintenance script to run a database query in batches and wait for replica DBs.
31 * @ingroup Maintenance
33 class BatchedQueryRunner
extends Maintenance
{
34 public function __construct() {
35 parent
::__construct();
36 $this->addDescription(
37 "Run a query repeatedly until it affects 0 rows, and wait for replica DBs in between.\n" .
38 "NOTE: You need to set a LIMIT clause yourself." );
41 public function execute() {
42 if ( !$this->hasArg() ) {
43 $this->error( "No query specified. Specify the query as a command line parameter.", true );
46 $query = $this->getArg();
48 $dbw = $this->getDB( DB_MASTER
);
50 $this->output( "Batch $n: " );
52 $dbw->query( $query, __METHOD__
);
53 $affected = $dbw->affectedRows();
54 $this->output( "$affected rows\n" );
56 } while ( $affected > 0 );
59 public function getDbType() {
60 return Maintenance
::DB_ADMIN
;
64 $maintClass = "BatchedQueryRunner";
65 require_once RUN_MAINTENANCE_IF_MAIN
;