Re: limiting hint bit I/O

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2011-01-14T18:06:03Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Jan 14, 2011 at 12:47 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Moreover this whole business of not treating hint-bit setting as
>> a page-dirtying operation is completely experimental/unproven IMO, so it
>> would be better to keep the patch footprint as small as possible.

> I have some concerns about that proposal, but it might be the right
> way to go.  Before we get too far off into the weeds, though, let's
> back up and talk about something more fundamental: this seems to be
> speeding up the first run by 6x at the expense of slowing down many
> subsequent runs by 10-15%.  Does that make this whole idea dead on
> arrival?

Well, it reinforces my opinion that it's experimental ;-).  But "first
run" of what, exactly?  And are you sure you're taking a wholistic view
of the costs/benefits?

			regards, tom lane