Re: add_path optimization

On Mon, Feb 2, 2009 at 8:10 PM, Kevin Grittner
<Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
>>>> Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> running this 5 times each on several queries,
>> dropping top and bottom results.
>
> Running a complex query (posted in previous threads, runs about
> 300,000 time per day in a production web application), I got these
> timings on a production quality machine (4 quad CPU chips, that is 16
> CPUs like this: Intel(R) Xeon(R) CPU X7350 @ 2.93GHz, 128 GB RAM, big
> RAID with BBU). I ran explain in each environment 5 times, tossed
> high and low, and averaged. The 8.4devel was from today's
> (2008-02-02) snapshot, built the same way we did 8.3.5.
>
> 8.3.5, statistics target 10: 36.188 ms
> 8.4devel without patch, statistics target 100: 109.862 ms
> 8.4devel with patch, statistics target 100: 104.015 ms
>
> After seeing that, I re-analyzed to eliminate the statistics target as
> the cause of the 8.4 increase.
>
> 8.4devel with patch, statistics target 10: 99.421 ms

Yikes! The impact of the patch is about what I'd expect, but the fact
that planning time has nearly tripled is... way poor. Can you repost
the query and the EXPLAIN output for 8.3.5 and CVS HEAD?

...Robert