Horton

Re: 16-bit page checksums for 9.2

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: Simon Riggs <simon@2ndquadrant.com>, Kevin Grittner <Kevin.Grittner@wicourts.gov>, david@fetter.org, aidan@highrise.ca, stark@mit.edu, pgsql-hackers@postgresql.org
Date: 2012-01-06T19:48:07Z
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 →

  1. Wakeup WALWriter as needed for asynchronous commit performance.

On Friday, January 06, 2012 08:45:45 PM Heikki Linnakangas wrote:
> On 06.01.2012 20:26, Simon Riggs wrote:
> > The following patch (v4) introduces a new WAL record type that writes
> > backup blocks for the first hint on a block in any checkpoint that has
> > not previously been changed. IMHO this fixes the torn page problem
> > correctly, though at some additional loss of performance but not the
> > total catastrophe some people had imagined. Specifically we don't need
> > to log anywhere near 100% of hint bit settings, much more like 20-30%
> > (estimated not measured).
> 
> How's that going to work during recovery? Like in hot standby.
How's recovery a problem? Unless I miss something that doesn't actually 
introduce a new possibility to transport hint bits to the standby (think 
fpw's). A new transport will obviously increase traffic but ...

Andres