On Mon, Sep 2, 2013 at 3:16 PM, Jeff Davis <pg...@j-davis.com> wrote: > On Fri, 2013-08-30 at 20:34 +0200, Andres Freund wrote: >> I have a quick question: The reason I'd asked about the status of the >> patch was that I was thinking about the state of the "forensic freezing" >> patch. After a quick look at your proposal, we still need to freeze in >> some situations (old & new data on the same page basically), so I'd say >> it still makes sense to apply the forensic freezing patch, right? >> >> Differing Opinions? > > The Freeze Forensically patch is nice because (if I understand it > correctly) it allows us to freeze at the same time as we mark > PD_ALL_VISIBLE, which avoids the potential extra page write.
The patch itself doesn't actually make that change, but it removes one major objection to such a change. > But that's > not such a big advantage if we don't ordinarily have to write again for > freezing, anyway. That was my thought as well. > However, there are still some cases where we'd be able to preserve the > forensic information. If nothing else, that might help debug this patch, > if necessary. There might also be cases where we can freeze more eagerly > to avoid the case where very old (but unfrozen) and very new tuples mix > on the same page. Perhaps Robert has some thoughts here, as well. I basically agree. I think if we adopt Heikki's patch forensic freezing becomes much less important, but we might find there's still a reason to do it. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
