I think IB/ FB benefits most from least on the left as it compresses using
"run length encoding" on the index stubb.

JAC.
I wake up sure, then become less so as the day goes on.



""csswa"" <csswa@...> wrote in message
news:ac2ckl+10ao@......

> This from an MSSQL7 site:
>
> "When you create an index with a composite key, the order of the
> columns in the key is important. Try to order the columns in the key
> as to enhance selectivity, with the most selective columns to the
> leftmost of the key. If you don't due this, and put a non-selective
> column at the first part of the key, you risk having the Query
> Optimizer not use the index at all."
>
> I was under the impression that you order left to right, least
> selective to most selective field -- the opposite of what this guy
> says. I was thinking that least selective first makes for a more
> balanced b-tree. No?
>
> Regards,
> Andrew Ferguson
> -- I have an unhealthy obsession with Freud's mom.
>
>
>
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