Re: warning message in standby

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
Cc: Simon Riggs <simon(at)2ndquadrant(dot)com>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, Magnus Hagander <magnus(at)hagander(dot)net>, Bruce Momjian <bruce(at)momjian(dot)us>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: warning message in standby
Date: 2010-07-02 21:47:20
Message-ID: AANLkTimkVIdAZgRgfZZ6BqRn2WFRmJryrFuEY72G_TDO@mail.gmail.com
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On Tue, Jun 29, 2010 at 10:58 AM, Kevin Grittner
<Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
>>> If someone is sloppy about how they copy the WAL files around,
>>> they could temporarily have a truncated file.
>>
>> Can you explain the scenario you're concerned about in more
>> detail?
>
> If someone uses cp or scp to copy a WAL file from the pg_xlog
> directory to an archive directory, there will be a window of time
> where the file exists and is not complete.  If you wait "a while"
> (that being a duration which could be highly variable, depending on
> the specifics of the environment and copy techniques used), the
> missing part of the file will materialize.

Drat. It looks like we even recommend that configuration in the docs.

Well, I don't know what to do about this, then, but I predict
somebody's going to get bitten by it... hard.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company

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