Date: Fri, 6 Mar 2020 09:48:58 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Magnus Hagander <magnus@hagander.net>
Cc: David Steele <david@pgmasters.net>,
	pgsql-committers <pgsql-committers@lists.postgresql.org>
Subject: Re: pgsql: Avoid -Wconversion warnings when using checksum_impl.h
Message-ID: <20200306004826.GB52814@paquier.xyz>
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On Thu, Mar 05, 2020 at 04:14:20PM -0800, Magnus Hagander wrote:
> That's a pretty dangerous mistake, and moreso because we don't have a
> test around it. We should really find a way to add such a test -- just
> a hardcoded page calculation that should always return the same value
> perhaps?

Yes..  Using pg_checksums --check on an upgraded instance which had
checksums enabled would detect that immediately, but it could be
possible also to have a SQL-callable function which takes in input a
bytea and returns the checksum.  In order to make such tests reliable
with any page size, we could pass down the page size to
pg_checksum_page(), and then give the function's caller this
possibility.  However I recall that we'd rather keep BLCKSZ hardcoded
in checksum_impl.h on performance grounds.
--
Michael

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