From: Noah Misch <noah@leadboat.com>
To: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: Nathan Bossart <nathandbossart@gmail.com>
Cc: David Steele <david@pgmasters.net>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: robertmhaas@gmail.com
Cc: masao.fujii@oss.nttdata.com
Cc: pgsql-hackers@postgresql.org
Subject: Re: remove more archiving overhead
Date: Mon, 19 Sep 2022 07:39:23 -0700
Message-ID: <20220919143923.GA1706070@rfd.leadboat.com> (raw)
In-Reply-To: <7476bc05-3b8d-dab4-64e9-b569c54631d6@enterprisedb.com>
References: <20220708.105652.1551158050191356887.horikyota.ntt@gmail.com>
<44dbf5e4-8eec-da56-daba-755128b3723e@pgmasters.net>
<20220708165450.GA2356733@nathanxps13>
<20220731065156.GA3694276@rfd.leadboat.com>
<20220802050219.GA475090@nathanxps13>
<20220803071617.GA3817792@rfd.leadboat.com>
<ebb0f19f-5452-678c-0d19-1b8b260fd331@enterprisedb.com>
<20220917215427.GB3189289@nathanxps13>
<20220918071312.GB1658466@rfd.leadboat.com>
<7476bc05-3b8d-dab4-64e9-b569c54631d6@enterprisedb.com>
On Mon, Sep 19, 2022 at 06:08:29AM -0400, Peter Eisentraut wrote:
> On 18.09.22 09:13, Noah Misch wrote:
> >>>This documentation change only covers archive_library. How are users of
> >>>archive_command supposed to handle this?
> >>
> >>I believe users of archive_command need to do something similar to what is
> >>described here. However, it might be more reasonable to expect
> >>archive_command users to simply return false when there is a pre-existing
> >>file, as the deleted text notes. IIRC that is why I added that sentence
> >>originally.
> >
> >What makes the answer for archive_command diverge from the answer for
> >archive_library?
>
> I suspect what we are really trying to say here is
>
> ===
> Archiving setups (using either archive_command or archive_library) should be
> prepared for the rare case that an identical archive file is being archived
> a second time. In such a case, they should compare that the source and the
> target file are identical and proceed without error if so.
>
> In some cases, it is difficult or impossible to configure archive_command or
> archive_library to do this. In such cases, the archiving command or library
> should error like in the case for any pre-existing target file, and
> operators need to be prepared to resolve such cases manually.
> ===
>
> Is that correct?
I wanted it to stop saying anything like the second paragraph, hence commit
d263ced. Implementing a proper archiving setup is not especially difficult,
and inviting the operator to work around a wrong implementation invites
damaging mistakes under time pressure.
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To: pgsql-hackers@postgresql.org
Cc: noah@leadboat.com, peter.eisentraut@enterprisedb.com, nathandbossart@gmail.com, david@pgmasters.net, horikyota.ntt@gmail.com, robertmhaas@gmail.com, masao.fujii@oss.nttdata.com
Subject: Re: remove more archiving overhead
In-Reply-To: <20220919143923.GA1706070@rfd.leadboat.com>
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