	private function _lastrevisionbefore( $option ) {
		$this->addTable( 'revision_actor_temp', 'rev' );
		$this->addSelect( [ 'rev.revactor_rev', 'rev.revactor_timestamp' ] );
		// tell the query optimizer not to look at rows that the following subquery will filter out anyway
		$this->addWhere(
			[
				$this->tableNames['page'] . '.page_id = rev.revactor_page',
				'rev.revactor_timestamp < ' . $this->convertTimestamp( $option )
			]
		);
		$this->addWhere(
			[
				$this->tableNames['page'] . '.page_id = rev.revactor_page',
				'rev.revactor_timestamp = (SELECT MAX(rev_aux_bef.revactor_timestamp) FROM ' . $this->tableNames['revision_actor_temp'] . ' AS rev_aux_bef WHERE rev_aux_bef.revactor_page=rev.revactor_page AND rev_aux_bef.revactor_timestamp < ' . $this->convertTimestamp( $option ) . ')'
			]
		);
	}
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.