$dbr = wfGetDB( DB_MASTER ); // Info might be out of date, somewhat fractionally, on slave.
$log_id = $dbr->selectField( 'recentchanges', 'rc_logid', array( 'rc_id' => $rc_id ), __METHOD__ );
$rev_id = $dbr->selectField( 'recentchanges', 'rc_this_oldid', array( 'rc_id' => $rc_id ), __METHOD__ );
$dbr = wfGetDB( DB_MASTER ); // Info might be out of date, somewhat fractionally, on slave.
$log_id = $dbr->selectField( 'recentchanges', 'rc_logid', array( 'rc_id' => $rc_id ), __METHOD__ );
$rev_id = $dbr->selectField( 'recentchanges', 'rc_this_oldid', array( 'rc_id' => $rc_id ), __METHOD__ );