From: Tom Lane <tgl@sss.pgh.pa.us>
To: Arnaud Lesauvage <thewild@freesurf.fr>
Cc: Ragnar <gnari@hive.is>
Cc: Jens Schipkowski <jens.schipkowski@apus.co.at>
Cc: pgsql-performance@postgresql.org
Subject: Re: Slow update with simple query
Date: Wed, 13 Dec 2006 11:46:25 -0500
Message-ID: <8399.1166028385@sss.pgh.pa.us> (raw)
In-Reply-To: <45801A1B.6070200@freesurf.fr>
References: <457FDB1E.6040801@freesurf.fr>
<op.tkhy4jpg81rjf6@xjens.apus.local>
<457FF0CD.4050606@freesurf.fr>
<op.tkh10qgw81rjf6@xjens.apus.local>
<4580025D.2040903@freesurf.fr>
<1166021340.6369.103.camel@localhost.localdomain>
<45801A1B.6070200@freesurf.fr>
Arnaud Lesauvage <thewild@freesurf.fr> writes:
> Indeed, the new query does not perform that well :
> "Hash Join (cost=112.75..307504.97 rows=2024869 width=355) (actual time=53.995..246443.811 rows=2020061 loops=1)"
> ...
> "Total runtime: 2777844.892 ms"
> I removed all unnecessary indexes on t1 before running the query (I left the index on uid and the multicolumn index containind the updated field).
> I believe the multicolumn-functional-index computation is taking some time here, isn't it ?
Given that the plan itself only takes 246 sec, there's *something*
associated with row insertion that's eating the other 2500+ seconds.
Either index entry computation or constraint checking ...
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, thewild@freesurf.fr, gnari@hive.is, jens.schipkowski@apus.co.at
Subject: Re: Slow update with simple query
In-Reply-To: <8399.1166028385@sss.pgh.pa.us>
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