From: David Steele <david@pgmasters.net>
To: Michael Paquier <michael@paquier.xyz>
To: Magnus Hagander <magnus@hagander.net>
Cc: pgsql-committers <pgsql-committers@lists.postgresql.org>
Subject: Re: pgsql: Avoid -Wconversion warnings when using checksum_impl.h
Date: Thu, 5 Mar 2020 19:58:50 -0500
Message-ID: <e19fa62e-f140-306a-aa6b-fb55ccb3b9c1@pgmasters.net> (raw)
In-Reply-To: <20200306004826.GB52814@paquier.xyz>
References: <E1j9ioh-0005Kn-4O@gemulon.postgresql.org>
<1cf30561-7dad-dc6e-9fc3-5c456948cfeb@pgmasters.net>
<20200305233014.GA2501@paquier.xyz>
<CABUevEzoWeR_q-JztqacmATBvVMUL9rtOcpM5RACubKcmhmk3Q@mail.gmail.com>
<20200306004826.GB52814@paquier.xyz>
On 3/5/20 7:48 PM, Michael Paquier wrote:
> 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.
Yeah, keeping BLKSZ a constant is pretty important for performance.
That's one of the main reasons that we only support the default.
Regards,
--
-David
david@pgmasters.net
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To: pgsql-committers@postgresql.org
Cc: david@pgmasters.net, michael@paquier.xyz, magnus@hagander.net, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Avoid -Wconversion warnings when using checksum_impl.h
In-Reply-To: <e19fa62e-f140-306a-aa6b-fb55ccb3b9c1@pgmasters.net>
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