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To: "Pavan Deolasee" <pavan.deolasee@gmail.com>
cc: "Heikki Linnakangas" <heikki@enterprisedb.com>,
	"Craig Ringer" <craig@postnewspapers.com.au>,
	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
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Comments: In-reply-to "Pavan Deolasee" <pavan.deolasee@gmail.com>
	message dated "Wed, 12 Mar 2008 21:17:20 +0530"
Date: Wed, 12 Mar 2008 11:57:19 -0400
Message-ID: <19902.1205337439@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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"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