| From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Removing more vacuumlazy.c special cases, relfrozenxid optimizations |
| Date: | 2022-03-23 20:58:31 |
| Message-ID: | CAH2-Wzk1zSyD_3JnYag7pO9bnVHCM1QEUA_3+XbgzF8gGA-nRw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Wed, Mar 23, 2022 at 1:53 PM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> I see what you mean about it depending on how you define "skipping".
> But I think that DISABLE_PAGE_SKIPPING is intended as a sort of
> emergency safeguard when you really, really don't want to leave
> anything out.
I agree.
> And therefore I favor defining it to mean that we don't
> skip any work at all.
But even today DISABLE_PAGE_SKIPPING won't do pruning when we cannot
acquire a cleanup lock on a page, unless it happens to have XIDs from
before FreezeLimit (which is probably 50 million XIDs behind
OldestXmin, the vacuum_freeze_min_age default). I don't see much
difference.
Anyway, this isn't important. I'll just drop the third patch.
--
Peter Geoghegan
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