Horton

Re: Setting pd_lower in GIN metapage

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Michael Paquier <michael.paquier@gmail.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Masahiko Sawada <sawada.mshk@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2017-09-19T15:47:09Z
Lists: pgsql-hackers 
Amit Kapila <amit.kapila16@gmail.com> writes:
> On Tue, Sep 19, 2017 at 9:27 AM, Michael Paquier
> <michael.paquier@gmail.com> wrote:
>> I am not saying that no index AMs take advantage FPW compressibility
>> for their meta pages. There are cases like this one, as well as one
>> code path in BRIN where this is useful, and it is useful as well when
>> logging FPWs of the init forks for unlogged relations.

> Hmm, why is it useful for logging FPWs of the init forks for unlogged
> relations?  We don't use REGBUF_STANDARD in those cases.

But if we started to do so, that would be a concrete benefit of this
patch ...

			regards, tom lane

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.