From: | Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Matteo Beccati <php(at)beccati(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: -HEAD planner issue wrt hash_joins on dbt3 ? |
Date: | 2006-09-22 16:56:00 |
Message-ID: | 451415A0.2090608@kaltenbrunner.cc |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Tom Lane wrote:
> Matteo Beccati <php(at)beccati(dot)com> writes:
>> Tom Lane ha scritto:
>>> Matteo Beccati <php(at)beccati(dot)com> writes:
>>>> I cannot see anything bad by using something like that:
>>>> if (histogram is large/representative enough)
>>> Well, the question is exactly what is "large enough"? I feel a bit
>>> uncomfortable about applying the idea to a histogram with only 10
>>> entries (especially if we ignore two of 'em). With 100 or more,
>>> it sounds all right. What's the breakpoint?
>
>> Yes, I think 100-200 could be a good breakpoint.
>
> I've committed this change with (for now) 100 as the minimum histogram
> size to use. Stefan, are you interested in retrying your benchmark?
sure - but I'm having hardware (harddisk firmware) related issues on my
testbox which will take a few further days to be resolved ...
Stefan
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2006-09-22 16:56:35 | Re: 8.3 Development Cycle |
Previous Message | Andrew Dunstan | 2006-09-22 16:55:56 | Re: 8.3 Development Cycle |