Re: [WIP] Performance Improvement by reducing WAL for Update Operation

From: Heikki Linnakangas [mailto:heikki.linnakangas@enterprisedb.com] 
Sent: Thursday, August 09, 2012 4:59 PM
On 09.08.2012 14:11, Simon Riggs wrote:

>>> But then again, full-page writes cover that too. There
>>> will be a full-page image of the old block in the WAL anyway.
>
>> Right, but we're planning to remove that, so its not a safe assumption
>> to use when building new code.

> I don't think we're going to get rid of full-page images any time soon. 
> I guess you could easily check if full-page writes are enabled, though, 
> and only do it for cross-page updates if it is.

According to my understanding you are talking about corruption due to
partial page writes which can be handled by full-page image of WAL. Correct
me if I misunderstood.
Based on that, even if full-page image is removed it will be maintained by
double buffer write[an alternative solution to full-page writes for some of
the paths] for the case of corrupt page handling.

With Regards,
Amit Kapila.