Re: Solving the OID-collision problem

On Tue, 2005-08-09 at 16:01 +0100, Richard Huxton wrote:
> Tom Lane wrote:
> >
> > What if there aren't any "untouched chunks"? With only 64K-chunk
> > granularity, I think you'd hit that condition a lot more than you are
> > hoping. Also, this seems to assume uniqueness across all tables in an
> > entire cluster, which is much more than we want; it makes the 32-bit
> > size of OIDs significantly more worrisome than when they only need to be
> > unique within a table.
>
> Can I ask what happens if we end up re-using a recently de-allocated
> OID? Specifically, can a cached plan (e.g. plpgsql function) end up
> referring to an object created after it was planned:
>
> CREATE FUNCTION f1()... -- oid=1234
> CREATE FUNCTION f2()... -- oid=1235, calls f1() or oid=1234
> DROP FUNCTION f1()
> CREATE FUNCTION f3()... -- re-uses oid=1234

Possible, but extremely unlikely... you'd have to keep a session open
with a prepared query for as long as it takes to create a 4 billion
tables... not a high priority case, eh?

Best Regards, Simon Riggs