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

From: Simon Riggs [mailto:simon(at)2ndQuadrant(dot)com]
Sent: Thursday, August 09, 2012 5:29 PM
On 9 August 2012 12:17, Amit Kapila <amit(dot)kapila(at)huawei(dot)com> wrote:

>> This optimization is to reduce the amount of WAL and definitely adding
>> anything extra will have some impact.

> Of course. The question is "How much impact?". Each tweak has
> progressively less and less gain. This isn't a binary choice.

> Squeezing the last ounce of performance at the expense of all other
> concerns is not a sensible goal, IMHO, nor do we attempt that
> elsewhere.

> Given we're making no attempt to remove full page writes, which is
> clearly the biggest source of WAL volume currently, micro optimisation
> of other factors seems unwarranted at this stage.

What I am pointing from WAL reduction is about Update operation performance
and
full-page writes doesn't have direct correlation with Update operation
except for
a case of first time update of page after checkpoint.

With Regards,
Amit Kapila.