Re: posix_fadvise missing in the walsender - Mailing list pgsql-hackers

From Robert Haas
Subject Re: posix_fadvise missing in the walsender
Date
Msg-id CA+TgmobgNgDTU3YzZ=iaRjUgFvQcLbVS5Yd9V41PKh0g=fZLfg@mail.gmail.com
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In response to Re: posix_fadvise missing in the walsender  (Jeff Janes <jeff.janes@gmail.com>)
List pgsql-hackers
On Thu, Feb 21, 2013 at 12:16 PM, Jeff Janes <jeff.janes@gmail.com> wrote:
> Does the kernel really read a data block from disk into memory in
> order to immediately overwrite it?  I would have thought it would
> optimize that away, at least if the writes are sized and aligned to
> 512 or 1024 bytes blocks (which WAL should be).

Now that you mention that I agree it seems strange, but that's what I saw.

/me scratches head

It does seem pretty odd, though.

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



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