From: Tom Lane <tgl@sss.pgh.pa.us>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
        Tomas Vondra <tomas.vondra@2ndquadrant.com>,
        Masahiko Sawada <masahiko.sawada@2ndquadrant.com>,
        "tsunakawa.takay@fujitsu.com" <tsunakawa.takay@fujitsu.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: SLRU statistics
In-reply-to: <bfe31847-78ce-7158-d917-dbdb9f49749b@oss.nttdata.com>
References: <20200513161406.GA437@alvherre.pgsql>
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 <bfe31847-78ce-7158-d917-dbdb9f49749b@oss.nttdata.com>
Comments: In-reply-to Fujii Masao <masao.fujii@oss.nttdata.com>
	message dated "Thu, 14 May 2020 11:18:53 +0900"
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Date: Wed, 13 May 2020 22:24:48 -0400
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Fujii Masao <masao.fujii@oss.nttdata.com> writes:
> On 2020/05/14 2:44, Tom Lane wrote:
>> I got through check-world with the assertion shown that we are not
>> counting any SLRU operations in the postmaster.  Don't know if we
>> want to commit that or not --- any thoughts?

> +1 to add this assertion because basically it's not good thing
> to access to SLRU at postmaster and we may want to fix that if found.
> At least if we get rid of the SLRUStats initialization code,
> IMO it's better to add this assertion and ensure that postmaster
> doesn't update the SLRU stats counters.

Seems reasonable --- I'll include it.

It might be nice to have similar assertions protecting BgWriterStats.
But given that we've made that public to be hacked on directly by several
different modules, I'm not sure that there's any simple way to do that.

			regards, tom lane