Re: ERROR: XX000: cache lookup failed for type 75083631

Jan Beseda <besedajohn(at)gmail(dot)com> writes:
> I'm having an issue with dropping a view as shown below:

> DROP VIEW access_group_view;
> ERROR: XX000: cache lookup failed for type 75083631
> LOCATION: format_type_internal, format_type.c:152

Does the behavior change if you say CASCADE?

The fact that it's failing in format_type() implies that something is
trying to print the name of a type, which doesn't seem like a main-line
activity for DROP VIEW. I am suspicious that pg_depend shows this type
OID as dependent for some reason on this view, and that the message
that it was trying to print was complaining about how that dependency
existed and that you'd need to say CASCADE to make it take. However,
since format_type() fails, the type OID must not really exist anymore,
implying that the pg_depend entry is orphaned.

That raises a different set of questions about how it got to be that way.
But at any rate, what I'd suggest is

1. Verify that the type OID is wrong:
select * from pg_type where oid = 75083631;
If that finds a row then we've got a whole other set of issues.
(BTW, if you want to be really sure, forcing a seqscan for this
query or reindexing pg_type could be advisable.)

2. Check for bogus entries in pg_depend:
select * from pg_depend where objid = 75083631;
select * from pg_depend where refobjid = 75083631;

3. If there's just one hit in pg_depend then it's probably
safe to delete that row.

regards, tom lane