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Re: Influence of index structure to insert performance

From: <xhoster_at_gmail.com>
Date: 17 Feb 2006 17:40:05 GMT
Message-ID: <20060217124135.398$i3@newsreader.com>


"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote:
> It is possible for the performance on insertions
> to be affected by column ordering in indexes, but
> in many cases the effect is likely to be something
> that gets lost in the general "noise" level of activity.
>
> To demonstrate the concept:
> Imagine you have a high volume insert
> (sydate, sequence_number, random_value)
>
> If your index is in the same column order then
> as you insert a row into the table, its insertion point
> in the index will (usually) be in the same index leaf
> block as last time - with the occasional fill, change
> of leaf block, and insertion into a branch block.
> This will maximise the benefit you can get from
> buffering and pinning.

On the other hand, if you have multiple processes running this insert statement it might also maximize the contention you get from pinning.

Xho

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Received on Fri Feb 17 2006 - 11:40:05 CST

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