Re: BUG #3826: Very Slow Execution of examplequery (wrong plan?) - Mailing list pgsql-bugs

From Alexander Steffens
Subject Re: BUG #3826: Very Slow Execution of examplequery (wrong plan?)
Date
Msg-id af11f8750904160522y3d60792cp770a54f03c203696@mail.gmail.com
Whole thread Raw
In response to Re: BUG #3826: Very Slow Execution of examplequery (wrong plan?)  ("Alexander Steffens" <steffens@math.uni-bonn.de>)
Responses Re: BUG #3826: Very Slow Execution of examplequery (wrong plan?)
List pgsql-bugs
Congratulations PostgreSQL-Team for your work!

with the current 8.4 B1 Version of PostgreSQL the bad execution time
of my example-Query containing a NOT EXISTS
changed from "aborted after hours" to just 5 seconds - double as quick
as my result with MS-SQL.

That's wonderful!

> insert into t1
> select distinct (t1.a + t2.a)*2
> from t1,t2
> where not exists (
>  select * from t1  tt where tt.a =3D (t1.a + t2.a)*2
> )

I assume there is now a hashed ANTI-SEMI-JOIN operator implemented?

Thanks

Alexander
--=20
Dipl.-Math. Alexander Steffens
Dorotheenstr. 16
23564 L=C3=BCbeck

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