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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Pavan Deolasee <pavan.deolasee@gmail.com>
Cc: Heikki Linnakangas <heikki@enterprisedb.com>
Cc: Craig Ringer <craig@postnewspapers.com.au>
Cc: pgsql-patches <pgsql-patches@postgresql.org>
Subject: Re: [PERFORM] Very slow (2 tuples/second) sequential scan after bulk insert; speed returns to ~500 tuples/second after commit
Date: Wed, 12 Mar 2008 11:57:19 -0400
Message-ID: <19902.1205337439@sss.pgh.pa.us> (raw)
In-Reply-To: <2e78013d0803120847k2e8afbedrc39e29e5194d3c6e@mail.gmail.com>
References: <47D505AF.4040101@postnewspapers.com.au>
	<47D5150C.8090802@enterprisedb.com>
	<23588.1205159638@sss.pgh.pa.us>
	<47D54A47.3030608@postnewspapers.com.au>
	<47D54DB2.4020405@enterprisedb.com>
	<24304.1205162440@sss.pgh.pa.us>
	<47D67C3F.1030406@enterprisedb.com>
	<5827.1205269597@sss.pgh.pa.us>
	<47D7DE12.80700@enterprisedb.com>
	<2e78013d0803120847k2e8afbedrc39e29e5194d3c6e@mail.gmail.com>

"Pavan Deolasee" <pavan.deolasee@gmail.com> writes:
> On Wed, Mar 12, 2008 at 7:13 PM, Heikki Linnakangas
> <heikki@enterprisedb.com> wrote:
>> Yep, patch attached. I also changed xactGetCommittedChildren to return
>> the original array instead of copying it, as Alvaro suggested.

> Any comments on the flag based approach I suggested earlier ?

I didn't like it; it seemed overly complicated (consider dealing with
XID wraparound), and it would have problems with a slow transaction
generating a sparse set of subtransaction XIDs.  I think getting rid of
the linear search will be enough to fix the performance problem.

			regards, tom lane



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  Subject: Re: [PERFORM] Very slow (2 tuples/second) sequential scan after bulk insert; speed returns to ~500 tuples/second after commit
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