Horton

Re: Setting pd_lower in GIN metapage

Amit Langote <langote_amit_f8@lab.ntt.co.jp>

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From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: Michael Paquier <michael.paquier@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2017-09-07T05:40:02Z
Lists: pgsql-hackers

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On 2017/09/07 13:09, Michael Paquier wrote:
> On Thu, Sep 7, 2017 at 12:59 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> The idea I'd had was to apply the masking only if pd_lower >=
>> SizeOfPageHeaderData, or if you wanted to be stricter, only if
>> pd_lower != 0.
> 
> If putting a check, it seems to me that the stricter one makes the
> most sense.

OK, patches updated that way.

> pd_lower should remain at 0 on pre-10 servers.

Doesn't PageInit(), which is where any page gets initialized, has always
set pd_lower to SizeOfPageHeaderData?

Thanks,
Amit

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.