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Re: correlated exists with join is slow.

From: Віталій Тимчишин <tivv00(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: correlated exists with join is slow.
Date: 2012-06-18 15:02:32
Message-ID: CABWW-d2SHStw5dv-JNfc-t-uQe=6KOzc5-_jR3_nkbvUZKn6Nw@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
Glad to hear postgresql becomes better and better :)

2012/6/18 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>

> =?KOI8-U?B?96bUwcymyiD0yc3eydvJzg==?= <tivv00(at)gmail(dot)com> writes:
> > Today I've found a query that I thought will be fast turned out to be
> slow.
> > The problem is correlated exists with join - it does not want to make
> > correlated nested loop to make exists check.
>
> 9.2 will make this all better.  These are exactly the type of case where
> you need the "parameterized path" stuff.
>
>                        regards, tom lane
>

-- 
Best regards,
 Vitalii Tymchyshyn

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