Horton

Re: New vacuum option to do only freezing

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>, "Bossart, Nathan" <bossartn@amazon.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-04-16T14:26:08Z
Lists: pgsql-hackers 
On Mon, Apr 15, 2019 at 9:07 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > I'm not sure that's correct.  If you do that, it'll end up in the
> > non-tupgone case, which might try to freeze a tuple that should've
> > been removed.  Or am I confused?
>
> If we're failing to remove it, and it's below the desired freeze
> horizon, then we'd darn well better freeze it instead, no?

I don't know that that's safe.  IIRC, the freeze code doesn't cope
nicely with being given a tuple that actually ought to have been
deleted.  It'll just freeze it anyway, which is obviously bad.

Unless this has been changed since I last looked at it.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Add toast-level reloption for vacuum_index_cleanup

  2. heap_prepare_freeze_tuple: Simplify coding

  3. Fix missing word.

  4. Allow VACUUM to be run with index cleanup disabled.

  5. Don't mark pages all-visible spuriously