From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Mariel Cherkassky <mariel.cherkassky@gmail.com>
Cc: Sergei Kornilov <sk@zsrv.org>
Cc: pgsql-admin@lists.postgresql.org
Subject: Re: checkpoint occurs very often when vacuum full running
Date: Sat, 17 Nov 2018 20:28:10 +0100
Message-ID: <69cd4eb6a9686eab9319f864db15942ec06fe86c.camel@cybertec.at> (raw)
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Mariel Cherkassky wrote:
> thank you for the explanation but I still got a few questions about this subject :
> 1.By physical location of the data do you mean the location on disk of the objects?
> I mean i thought that the wal files containing the logical changes , for example
> If I run an update then the wal file will contain the update in some format.
> Can you explain then what exactly it contains and what you meant by physical ?
It does *not* contain the SQL executed - how'd that work with functions like
"random"?
Rather, the information is like "replace the 42 bytes from offset 99 of block 12
in file xy with these bytes: ...".
> 2.So If the vacuum full stopped in some brutal way (kill -9 or the disk run of space)
> does all the new data files that are created deleted or left on the storage as orphan files ?
In an out of space scenario, the files would get removed.
If you kill -9 the backend they will be left behind.
Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com
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To: pgsql-performance@postgresql.org
Cc: laurenz.albe@cybertec.at, mariel.cherkassky@gmail.com, sk@zsrv.org, pgsql-admin@lists.postgresql.org
Subject: Re: checkpoint occurs very often when vacuum full running
In-Reply-To: <69cd4eb6a9686eab9319f864db15942ec06fe86c.camel@cybertec.at>
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