Message-ID: <d0480c1e584150863fdecd9f83ed56a8b4e88a72.camel@j-davis.com>
Subject: Re: New strategies for freezing, advancing relfrozenxid early
From: Jeff Davis <pgsql@j-davis.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: Tue, 30 Aug 2022 23:28:46 -0700
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On Tue, 2022-08-30 at 13:45 -0700, Peter Geoghegan wrote:
> It's that I believe
> that it is all but mandatory for me to ameliorate the downside that
> goes with more eager freezing, for example by not doing it at all
> when
> it doesn't seem to make sense. I want to solve the big problem of
> freeze debt, without creating any new problems. And if I should also
> make things in adjacent areas better too, so much the better.

That clarifies your point. It's still a challenge for me to reason
about which of these potential new problems really need to be solved in
v1, though.

> Why stop at a couple of dozens of lines of code? Why not just change
> the default of vacuum_freeze_min_age and
> vacuum_multixact_freeze_min_age to 0?

I don't think that would actually solve the unbounded buildup of
unfrozen pages. It would still be possible for pages to be marked all
visible before being frozen, and then end up being skipped until an
aggressive vacuum is forced, right?

Or did you mean vacuum_freeze_table_age?

Regards,
	Jeff Davis