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Re: What index access path does INDEX_SS yield ?

From: John K. Hinsdale <hin_at_alma.com>
Date: 2 Jan 2007 04:03:52 -0800
Message-ID: <1167739432.251162.222510@48g2000cwx.googlegroups.com>


Jonathan Lewis wrote:

> ... as soon as you use the index_ss() hint, it forces Oracle
> to cost for a skip scan on every single index - even the
> ones where a 'real' skip scan is impossible ... because a
> range/full scan is only a special case of a skip scan.
>
> If, after following this directive, the cost for an index
> full scan on a 'silly' index is less than the cost of using
> an index with a "genuine" skip scan capability, then Oracle
> has to use the "silly" index.

This explanation is both plausible and enlightening, thanks!

Received on Tue Jan 02 2007 - 06:03:52 CST

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