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Re: [PERFORM] Very slow (2 tuples/second) sequentialscan after bulk insert; speed returns to ~500 tuples/second aftercommit

From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Craig Ringer <craig(at)postnewspapers(dot)com(dot)au>, pgsql-patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: [PERFORM] Very slow (2 tuples/second) sequentialscan after bulk insert; speed returns to ~500 tuples/second aftercommit
Date: 2008-03-11 13:29:04
Message-ID: 20080311132904.GA9116@alvh.no-ip.org (view raw or flat)
Thread:
Lists: pgsql-patchespgsql-performance
Heikki Linnakangas wrote:

> I couldn't let this case go, so I wrote a patch. I replaced the linked  
> list with an array that's enlarged at AtSubCommit_childXids when 
> necessary.

Do you still need to palloc the return value from
xactGetCommittedChildren?  Perhaps you can save the palloc/memcpy/pfree
and just return the pointer to the array already in memory?

Not that it'll any much of a performance impact, but just for
cleanliness :-)

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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