Horton

Re: double writes using "double-write buffer" approach [WIP]

Fujii Masao <masao.fujii@gmail.com>

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From: Fujii Masao <masao.fujii@gmail.com>
To: Dan Scales <scales@vmware.com>
Cc: PG Hackers <pgsql-hackers@postgresql.org>
Date: 2012-02-06T11:08:15Z
Lists: pgsql-hackers 
On Sat, Jan 28, 2012 at 7:31 AM, Dan Scales <scales@vmware.com> wrote:
> Let me know if you have any thoughts/comments, etc.  The patch is
> enclosed, and the README.doublewrites is updated a fair bit.

ISTM that the double-write can prevent torn-pages in neither double-write file
nor data file in *base backup*. Because both double-write file and data file can
be backed up while being written. Is this right? To avoid the torn-page problem,
we should write FPI to WAL during online backup even if the double-write has
been committed?

Regards,

-- 
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center