Re: Setting pd_lower in GIN metapage

From: Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp>
To: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Setting pd_lower in GIN metapage
Date: 2017-09-07 05:40:02
Message-ID: 785036ff-b597-e6cf-acd8-519fc03d7215@lab.ntt.co.jp
Views: Raw Message | Whole Thread | Download mbox
Thread:
Lists: pgsql-hackers

On 2017/09/07 13:09, Michael Paquier wrote:
> On Thu, Sep 7, 2017 at 12:59 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)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

Attachment Content-Type Size
0001-Set-pd_lower-correctly-in-the-GIN-metapage.patch text/plain 2.8 KB
0002-Set-pd_lower-correctly-in-the-BRIN-index-metapage.patch text/plain 1.8 KB
0003-Set-pd_lower-correctly-in-the-SP-GiST-index-metapage.patch text/plain 1.7 KB

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Thomas Munro 2017-09-07 05:45:52 Re: Causal reads take II
Previous Message Amit Kapila 2017-09-07 05:35:44 Re: Parallel Append implementation