Horton

Re: 16-bit page checksums for 9.2

Merlin Moncure <mmoncure@gmail.com>

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From: Merlin Moncure <mmoncure@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Robert Haas <robertmhaas@gmail.com>, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, 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: 2012-01-06T22:17:09Z
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 Fri, Jan 6, 2012 at 2:03 PM, Andres Freund <andres@anarazel.de> wrote:
>> The standby can set hint bits locally that weren't set on the data it
>> received from the master.  This will require rechecksumming and
>> rewriting the page, but obviously we can't write the WAL records
>> needed to protect those writes during recovery.  So a crash could
>> create a torn page, invalidating the checksum.
> Err. Stupid me, thanks.
>
>> Ignoring checksum errors during Hot Standby operation doesn't fix it,
>> either, because eventually you might want to promote the standby, and
>> the checksum will still be invalid.
> Its funny. I have the feeling we all are missing a very obvious brilliant
> solution to this...

Like getting rid of hint bits?

merlin