Alexey Borzov <borz_off(at)rdw(dot)ru> writes:
> Can I just delete the record in pg_relcheck, decrement the counter
> in pg_class and enjoy the results or will it have undesirable
> side-effects?
Should work; be careful to do the pg_class change last, else you'll
likely get inconsistency complaints. IIRC, the pg_class change will
trigger relation-cache reload for the table, and the indicated number
of records had better match pg_relcache when that happens.
regards, tom lane