Re: 16-bit page checksums for 9.2

Simon Riggs <simon@2ndquadrant.com>

From: Simon Riggs <simon@2ndQuadrant.com>

To: Robert Haas <robertmhaas@gmail.com>

Cc: Andres Freund <andres@anarazel.de>, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, Kevin Grittner <Kevin.Grittner@wicourts.gov>, david@fetter.org, aidan@highrise.ca, stark@mit.edu, pgsql-hackers@postgresql.org

Date: 2012-01-07T10:14:30Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Wakeup WALWriter as needed for asynchronous commit performance.
- 4de82f7d7c50 9.2.0 cited

On Fri, Jan 6, 2012 at 9:44 PM, Robert Haas <robertmhaas@gmail.com> wrote:

>> Writing pages during recovery doesn't need WAL. If we crash, we replay
>> using the already generated WAL.
>
> Which is all fine, except when you start making changes that are not
> WAL-logged.  Then, you have the same torn page problem that exists
> when you it in normal running.

Yes, of course. My point is that this is not a blocker to using
checksums, only that some actions cannot occur on the standby but the
replay of changes is not in danger.

page_checksums is an optional parameter, so you can turn it on or off
on the standby as you wish. People frequently have a standby dedicated
to HA and other standbys for queries. So this is all normal and
natural.

page_checksums will default to 'off' in the final patch anyway, in my
understanding.

-- 
 Simon Riggs                   http://www.2ndQuadrant.com/
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