Re: MCV lists for highly skewed distributions - Mailing list pgsql-hackers

From John Naylor
Subject Re: MCV lists for highly skewed distributions
Date
Msg-id CAJVSVGUebFUD3VxyKKSbFP7SLhSwvkSymGinVSQUcZ7X8QzkDg@mail.gmail.com
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In response to Re: MCV lists for highly skewed distributions  (Dean Rasheed <dean.a.rasheed@gmail.com>)
Responses Re: MCV lists for highly skewed distributions  (Dean Rasheed <dean.a.rasheed@gmail.com>)
List pgsql-hackers
On 2/2/18, Dean Rasheed <dean.a.rasheed@gmail.com> wrote:
> I think it would be better to try to come up with an alternative
> algorithm that has a better theoretical basis, and then test that to
> see how it holds up in practice.
>
> With that in mind, attached is a patch based on the idea of setting a
> bound on the relative standard error on the sample frequency

I did the same basic eyeball testing I did on earlier patches, and
this is the best implementation so far. I've attached some typical
pg_stats contents for HEAD and this patch. More rigorous testing,
including of planner estimates on real data, is still needed of
course, but I think this is definitely in the right direction.

-John Naylor

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