Re: limiting hint bit I/O

On Fri, Jan 14, 2011 at 2:51 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> On Fri, Jan 14, 2011 at 2:09 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> Freezing sooner isn't likely to reduce I/O compared to hint bits.  What
>>> that does is create I/O that you *have* to execute ... both in the pages
>>> themselves, and in WAL.
>
>> It depends on which way you tilt your head - right now, we rewrite
>> each table 3x - once to populate, once to hint, and once to freeze.
>> If the table is doomed to survive long enough to go through all three
>> of those, then freezing is better than hinting.  Of course, that's not
>> always the case, but people keep complaining about the way this shakes
>> out.
>
> The people whose tables are mostly insert-only complain about it, but
> that's not the majority of our userbase IMO.  We just happen to have a
> couple of particularly vocal ones, like Berkus.

True.

--
Robert Haas
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