Re: pg_relation_size / could not open relation with OID #

tv(at)fuzzy(dot)cz writes:
> I've run into a strange problem with system catalogs - we're collecting
> database stats periodically (every 10 minutes), and from time to time we
> get the following error:

> --------------------------------------------------
> ERROR: could not open relation with OID 154873708
> --------------------------------------------------

I think you're probably hitting a problem with a table being deleted
while you're scanning pg_class. pg_relation_size() will fail if the
given OID isn't valid "now" --- but the underlying query returns all
OIDs that were valid when the transaction or statement snapshot was
taken. So you have a race condition.

You might consider excluding temp tables from the query, if that's the
most likely source of the problem.

regards, tom lane