Re: limiting hint bit I/O

On 01/18/2011 06:44 PM, Robert Haas wrote:
> On Tue, Jan 18, 2011 at 9:24 AM, Merlin Moncure<mmoncure(at)gmail(dot)com> wrote:
>> a few weeks back I hacked an experimental patch that removed the hint
>> bit action completely. the results were very premature and/or
>> incorrect, but my initial findings suggested that hint bits might not
>> be worth the cost from performance standpoint. i'd like to see some
>> more investigation in this direction before going with a complex
>> application mechanism (although that would be beneficial vs the status
>> quo).
>
> I think it's not very responsible to allege that hint bits aren't
> providing a benefit without providing the patch that you used and the
> tests that you ran.

maybe I'm wrong but it seems it did post an experimental patch and also
a tests used, see:

http://archives.postgresql.org/pgsql-hackers/2010-12/msg01897.php

> This is a topic that needs careful analysis, and
> I think that saying "hint bits don't provide a benefit... maybe..."
> doesn't do anything but confuse the issue. How about doing some tests
> with the patch from my OP and posting the results? If removing hint
> bits entirely doesn't degrade performance, then surely the
> less-drastic approach I've taken here ought to be OK too. But in my
> testing, it didn't look too good.
>

Andrea