From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
---|---|
To: | Andres Freund <andres(at)2ndquadrant(dot)com> |
Cc: | Greg Smith <greg(at)2ndquadrant(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Ants Aasma <ants(at)cybertec(dot)at>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Jeff Davis <pgsql(at)j-davis(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Enabling Checksums |
Date: | 2013-03-29 01:02:06 |
Message-ID: | CA+TgmoZaui-41k_20EVJgt_DynVUdTrE5txjgawBy391b_uD1w@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Wed, Mar 27, 2013 at 10:15 AM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> On 2013-03-27 10:06:19 -0400, Robert Haas wrote:
>> On Mon, Mar 18, 2013 at 4:31 PM, Greg Smith <greg(at)2ndquadrant(dot)com> wrote:
>> > to get them going again. If the install had checksums, I could have figured
>> > out which blocks were damaged and manually fixed them, basically go on a
>> > hunt for torn pages and the last known good copy via full-page write.
>>
>> Wow. How would you extract such a block image from WAL?
>>
>> That would be a great tool to have, but I didn't know there was any
>> practical way of doing it today.
>
> Given pg_xlogdump that should be doable with 5min of hacking in 9.3. Just add
> some hunk to write out the page to the if (config->bkp_details) hunk in
> pg_xlogdump.c:XLogDumpDisplayRecord. I have done that for some debugging already.
>
> If somebody comes up with a sensible & simple UI for this I am willing to
> propose a patch adding it to pg_xlogdump. One would have to specify the
> rel/file/node, the offset, and the target file.
Hmm. Cool. But, wouldn't the hard part be to figure out where to
start reading the WAL in search of the *latest* FPI?
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
From | Date | Subject | |
---|---|---|---|
Next Message | Michael Paquier | 2013-03-29 01:17:53 | Re: Changing recovery.conf parameters into GUCs |
Previous Message | Brendan Jurd | 2013-03-29 00:12:59 | Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL) |