Re: [HACKERS] [COMMITTERS] pgsql: Fix freezing of a dead HOT-updatedtuple - Mailing list pgsql-committers

From Andres Freund
Subject Re: [HACKERS] [COMMITTERS] pgsql: Fix freezing of a dead HOT-updatedtuple
Date
Msg-id 20171207204622.2gxjhz7zepca5dbc@alap3.anarazel.de
Whole thread Raw
In response to Re: [HACKERS] [COMMITTERS] pgsql: Fix freezing of a dead HOT-updatedtuple  (Alvaro Herrera <alvherre@alvh.no-ip.org>)
List pgsql-committers
On 2017-12-07 17:41:56 -0300, Alvaro Herrera wrote:
> > > Looking at 0002: I agree with the stuff being done here.  I think a
> > > couple of these checks could be moved one block outerwards in term of
> > > scope; I don't see any reason why the check should not apply in that
> > > case.  I didn't catch any place missing additional checks.
> > 
> > I think I largely put them into the inner blocks because they were
> > guaranteed to be reached in those case (the horizon has to be before the
> > cutoff etc), and that way additional branches are avoided.
> 
> Hmm, it should be possible to call vacuum with a very low freeze_min_age
> (which sets a very recent relfrozenxid), then shortly thereafter call it
> with a large one, no?  So it's not really guaranteed ...

Fair point!

- Andres


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