From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: x4mmm@yandex-team.ru
Cc: dilipbalaut@gmail.com
Cc: tndrwang@gmail.com
Cc: pgsql-hackers@lists.postgresql.org
Cc: tomas.vondra@enterprisedb.com
Subject: Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock
Date: Mon, 04 Mar 2024 17:41:58 -0500
Message-ID: <3898618.1709592118@sss.pgh.pa.us> (raw)
In-Reply-To: <3885480.1709590472@sss.pgh.pa.us>
References: <202403031358.b435eh7u72td@alvherre.pgsql>
<3885480.1709590472@sss.pgh.pa.us>
I wrote:
> It looks like SLRU_PAGE_EMPTY has (by chance, or deliberately)
> the numeric value of zero, so I guess the majority of our BF
> animals are understanding this as "address != NULL". But that
> doesn't look like a useful test to be making.
In hopes of noticing whether there are other similar thinkos,
I permuted the order of the SlruPageStatus enum values, and
now I get the expected warnings from gcc:
In file included from ../../../../src/include/postgres.h:45,
from slru.c:59:
slru.c: In function ‘SimpleLruWaitIO’:
slru.c:436:38: warning: comparison between pointer and integer
Assert(&shared->page_status[slotno] != SLRU_PAGE_EMPTY);
^~
../../../../src/include/c.h:862:9: note: in definition of macro ‘Assert’
if (!(condition)) \
^~~~~~~~~
slru.c: In function ‘SimpleLruWritePage’:
slru.c:717:43: warning: comparison between pointer and integer
Assert(&ctl->shared->page_status[slotno] != SLRU_PAGE_EMPTY);
^~
../../../../src/include/c.h:862:9: note: in definition of macro ‘Assert’
if (!(condition)) \
^~~~~~~~~
So it looks like it's just these two places.
regards, tom lane
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Subject: Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock
In-Reply-To: <3898618.1709592118@sss.pgh.pa.us>
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