Manual:PurgeExpiredWatchlistItems.php

Details
purgeExpiredWatchlistItems.php is a maintenance script that deletes expired rows from the and  database tables.

This script should be run periodically, for example, by a cron job. The recommended periodicity is once or twice a day, to account for users on different timezones. For improved site performance, can be set to 0.

Options
This script doesn't have any of its own parameters, and the most useful of the generic parameters is probably, which determines how many rows will be deleted on each run (defaults to 500 ).

Common error
An error is thrown if is not true. Set  to enable.
 * Watchlist expiry is not enabled.