Re: Full page images in WAL & Cache Invalidation

"Florian G. Pflug" <fgp@phlo.org> writes:
> My basic assumption is that DDL is something quite uncommon on a
> production system.

I'm not sure I believe that, because of temp tables.  There's also
the problem that plain VACUUM (or ANALYZE) causes a relcache flush
to update the relation-size statistics.

The real problem with the scheme you propose is that it turns a
cache flush on one table into a system-wide cache flush.

We might be able to do something about the temp-table case upstream:
AFAICS there's no reason for backends to broadcast cache flushes for
their own temp tables to other backends.  But that's just a sketch
of a thought at the moment.

Anyway, if you believe that DDL is infrequent, why are you resistant
to the idea of WAL-logging cache flushes?
        regards, tom lane