Horton

Re: Setting pd_lower in GIN metapage

Michael Paquier <michael.paquier@gmail.com>

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From: Michael Paquier <michael.paquier@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Tom Lane <tgl@sss.pgh.pa.us>, Masahiko Sawada <sawada.mshk@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2017-09-14T10:47:37Z
Lists: pgsql-hackers 
On Thu, Sep 14, 2017 at 6:36 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> Why do we need to change metapage at every place for btree ...

I have been hunting for some time places where meta buffers were
marked as dirtied and logged. So in the effort, I think that my hands
and mind got hotter, forgetting that pd_lower is set there for ages.
Of course feel free to ignore that.

> ... or hash?
> Any index that is upgraded should have pd_lower set, do you have any
> case in mind where it won't be set?  For hash, if someone upgrades
> from a version lower than 9.6, it might not have set, but we already
> give warning to reindex the hash indexes upgraded from a version lower
> than 10.

Ah yes. You do set pd_lower in 10 as well for hash... So that will be
fine. So remains SpGist as a slacking AM based on the current patches.
-- 
Michael

Commits

  1. Flag index metapages as standard-format in xlog.c calls.

  2. Set the metapage's pd_lower correctly in brin, gin, and spgist indexes.