The SET MAXCOST statement restricts the maximum cost per query on the database in terms of disk I/O and CPU usage. The MAXCOST value must be less than or equal to the session's value for query_cost_limit. If no query_cost_limit is set, there is no limit on cost usage per query. To set query_cost_limit for a user, use the GRANT statement.

When maxcost is set, it remains in effect until another SET MAXCOST or SET NOMAXCOST statement is issued or the session terminates.

For more information, see query_cost_limit in the description of Grant (privilege) (see page GRANT (privilege)).