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Re: Index freelists

From: Nuno Souto <dbvision_at_optusnet.com.au>
Date: Thu, 29 Apr 2004 21:29:15 +1000
Message-ID: <00e801c42ddd$3caefda0$9b00a8c0@dcs001>

> snip
> But if you have contention on index segment's header block because of
block
> splits/freelist operations, then either partition the index or have
multiple
> freelist groups, adding freelists again won't help here. Note that adding
> freelist groups require segment rebuild.

Very interesting points, Tanel. I've discussed a similar situation with one of the local Oracle consultants here when 10G and ASSM/ASM were announced
(re-announced?) early last year.

We both reached the conclusion the best approach to contention problems in situations like these (header block contention) is to hash partition as much as we can (and dare) and forget about fine-tuning segment-headers, freelists and all that jazz. Much better bang-for-buck of our time. Same applies to RAC and clustered situations where there may be block (or row) contention.

Just hash partition the table + indexes over 50 or so splits and be done with it. 99 times out of 100 it's all you need to do, the remaining 1% you ask a guru to sort it out. Would you agree?

Cheers
Nuno Souto
in sunny Sydney, Australia
dbvision_at_optusnet.com.au



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Received on Thu Apr 29 2004 - 06:26:36 CDT

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