Re: limiting hint bit I/O - Mailing list pgsql-hackers

From Tom Lane
Subject Re: limiting hint bit I/O
Date
Msg-id 8493.1295028363@sss.pgh.pa.us
Whole thread Raw
In response to Re: limiting hint bit I/O  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: limiting hint bit I/O  (Robert Haas <robertmhaas@gmail.com>)
List 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


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