| From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
|---|---|
| To: | "Sven R(dot) Kunze" <srkunze(at)mail(dot)de> |
| Cc: | "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Multiple-Table-Spanning Joins with ORs in WHERE Clause |
| Date: | 2016-09-29 19:11:34 |
| Message-ID: | CAFj8pRCRooD2--9T2uQ8+A9X1v-ToM0VBkJmWoNuR8e4R9dgiQ@mail.gmail.com |
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| Lists: | pgsql-performance |
2016-09-29 20:49 GMT+02:00 Sven R. Kunze <srkunze(at)mail(dot)de>:
> On 29.09.2016 20:12, Pavel Stehule wrote:
>
>> In ideal world then plan should be independent on used form. The most
>> difficult is safe estimation of OR predicates. With correct estimation the
>> transformation to UNION form should not be necessary I am think.
>>
>
> Ah, okay. That's interesting.
>
> So how can I help here?
>
try to write a patch :) or better, help with enhancing PostgreSQL's
estimation model. Tomas Vondra is working 2 years on multicolumn
statistics. He needs help with review.
Regards
Pavel
>
> Regards,
> Sven
>
>
>
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