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: Simon Riggs <simon@2ndquadrant.com>
Cc: Kevin Grittner <Kevin.Grittner@wicourts.gov>, david@fetter.org, aidan@highrise.ca, stark@mit.edu, pgsql-hackers@postgresql.org
Date: 2012-01-06T19:35:01Z
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 07:26:14 PM 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).
Well, but it will hurt in those cases where hint bits already hurt hugely. 
Which is for example when accessing huge amounts of data the first time after 
loading it. Which is not exactly uncommon...

Andres