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@gmail.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