Re: could not open relation - why?

"Harald Armin Massa" <haraldarminmassa(at)gmail(dot)com> writes:
>> The easiest explanation is that someone dropped a table just as
>> autovacuum was trying to open it.

> I am not quite sure that "autovacuum" was trying to open, as some user
> reported the same error on his system ( and he is definitely not mr.
> Autovacuum :)

Oh, I assumed you had reason to think that the error message came from
autovacuum. It could easily have been the same situation except two
unrelated processes.

> What indeed happens alot in this database is the creation and the dropping
> of temp tables (the later automagically at the end of a connection, I
> assume)

Hmm ... but why would one process be trying to open another one's temp
table? The built-in stuff tries to avoid that, for the most part.
What was that user doing, exactly, when he got the error?

> Is there a way to learn to which dropped table OIDs belong, or is all gone
> after dropping and autovacuum ?

No, not easily --- once the table is dropped the info is gone. You
could try turning on log_error_statement so you could see what SQL
operation is provoking the error; that might help figure it out.

regards, tom lane