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

From: "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com>
To: "Alvaro Herrera" <alvherre(at)commandprompt(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 14:03:08
Message-ID: 47D6911C.3040605@enterprisedb.com
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Alvaro Herrera wrote:
> 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?

Yeah, good point. The callers just need to be modified not to pfree it.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

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