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Major performance problem after upgrade from 8.3 to 8.4

From: Gerhard Wiesinger <lists(at)wiesinger(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Major performance problem after upgrade from 8.3 to 8.4
Date: 2010-08-30 06:20:05
Message-ID: alpine.LFD.2.01.1008300802300.4121@bbs.intern (view raw or flat)
Thread:
Lists: pgsql-performance
Hello,

I just upgraded with pg_dump/restore from PostgreSQL 8.3.11 to 8.4.4 but 
I'm having major performance problems with a query with many left joins. 
Problem is that costs are now very, very, very high (was ok in 8.3). 
Analyze has been done. Indexes are of course there.

   ->  Merge Left Join 
(cost=1750660.22..4273805884876845789194861338991916289697885665127154313046252183850255795798561612107149662486528.00 
rows=238233578115856634454073334945297075430094545596765511255148896328828230572227215727052643001958400 
width=16)
         Merge Cond: (l.id = d2000903.fk_id)

Details with execution plan can be found at:
http://www.wiesinger.com/tmp/pg_perf_84.txt

I know that the data model is key/value pairs but it worked well in 8.3. I 
need this flexibility.

Any ideas?

Thnx.

Ciao,
Gerhard

--
http://www.wiesinger.com/


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Subject: Re: Major performance problem after upgrade from 8.3 to 8.4
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Subject: Re: Performance on new 64bit server compared to my 32bit desktop

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