From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Truncating Direct IO files
Date: Tue, 21 Apr 2015 09:47:24 +0200
Date: 2015-04-21T09:47:24+02:00 [thread overview]
Message-ID: <1tufk7ruhyejt.1tyb01i9kotm1.dlg@40tude.net> (raw)
In-Reply-To: 8323246f-eb13-49e8-9e0c-5c5ec1002060@googlegroups.com
On Tue, 21 Apr 2015 00:30:37 -0700 (PDT), tonyg wrote:
> I am recording records to disk. Sometimes I replace thes records with a
> smaller set of records.
Do you rewrite all file then? In that case you could simply work with a
copy and delete the original, in a sort of double-buffering manner.
> I could delete the file each time but would prefer to truncate the file. I
> can't see a way of doing this, can you?
There seems no way doing that without OS.
In my implementation of a persistent storage pool I simply maintain the
list of free elements and reuse them later.
BTW, I don't overwrite any file elements within single transaction. I don't
know what you are doing, but consider a scenario when the application or
the whole system crashes in the middle of file updating. Would that corrupt
the data?
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2015-04-21 7:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-21 7:30 Truncating Direct IO files tonyg
2015-04-21 7:47 ` Dmitry A. Kazakov [this message]
2015-04-21 8:20 ` tonyg
2015-04-21 9:17 ` Dmitry A. Kazakov
2015-04-21 22:01 ` Randy Brukardt
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