On 30.11.2010 18:10, Tom Lane wrote:
> Heikki Linnakangas<heikki.linnakangas@enterprisedb.com> writes:
>> Yeah, I'm not terribly excited about any of these schemes. The "intent"
>> record seems like the simplest one, but even that is quite different
>> from the traditional WAL-logging we do that it makes me slightly nervous.
>
> I'm not convinced it works at all. Consider write intent record,
> checkpoint, set bit, crash before completing vacuum. There will be
> no second intent record at which you could clean up if things are
> inconsistent.
That's why you need to check the RedoRecPtr when you set the bit. If it
has changed, ie. a checkpoint has happened, the set bit step will write
a new intent record.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com