From: Evan Carroll <lists@evancarroll.com>
To: pgsql-performance@postgresql.org
Subject: Fwd: 8.2 Query 10 times slower than 8.1 (view-heavy)
Date: Tue, 28 Aug 2007 11:24:57 -0500
Message-ID: <428b865e0708280924ye13ead1j5c198778cdea9c6@mail.gmail.com> (raw)
In-Reply-To: <428b865e0708280923k57b8cbe4l3dd01fca75975c3f@mail.gmail.com>
References: <428b865e0708280822u522391ecr5366bb5a6647f1aa@mail.gmail.com>
<dcc563d10708280832u4b0b9abbh1b5053bd1b2a9149@mail.gmail.com>
<428b865e0708280901x3776581qc424bb2c52531475@mail.gmail.com>
<dcc563d10708280907r4b67217eta560c8eab710ab3c@mail.gmail.com>
<428b865e0708280923k57b8cbe4l3dd01fca75975c3f@mail.gmail.com>
---------- Forwarded message ----------
From: Evan Carroll <me@evancarroll.com>
Date: Aug 28, 2007 11:23 AM
Subject: Re: [PERFORM] 8.2 Query 10 times slower than 8.1 (view-heavy)
To: Scott Marlowe <scott.marlowe@gmail.com>
On 8/28/07, Scott Marlowe <scott.marlowe@gmail.com> wrote:
> I looked through your query plan, and this is what stood out in the 8.2 plan:
>
> -> Nested Loop Left Join (cost=8830.30..10871.27 rows=1
> width=102) (actual time=2148.444..236018.971 rows=62 loops=1)
> Join Filter: ((public.contact.pkid =
> public.contact.pkid) AND (public.event.ts_in > public.event.ts_in))
> Filter: (public.event.pkid IS NULL)
>
> Notice the misestimation is by a factor of 62, and the actual time
> goes from 2149 to 236018 ms.
>
> Again, have you analyzed your tables / databases?
>
contacts=# \o scott_marlowe_test
contacts=# VACUUM FULL ANALYZE;
contacts=# SELECT * FROM test_view WHERE U_ID = 8;
Cancel request sent
ERROR: canceling statement due to user request
contacts=# EXPLAIN ANALYZE SELECT * FROM test_view WHERE U_ID = 8;
output found at http://rafb.net/p/EQouMI82.html
--
Evan Carroll
System Lord of the Internets
me@evancarroll.com
832-445-8877
--
Evan Carroll
System Lord of the Internets
me@evancarroll.com
832-445-8877
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To: pgsql-performance@postgresql.org
Cc: lists@evancarroll.com
Subject: Re: Fwd: 8.2 Query 10 times slower than 8.1 (view-heavy)
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