Re: Separate Index or Composite Indice ?

"userjohn" <userjohn_at_mailinator.com> wrote:
> 10gR2
>
> If you have :
> 2 columns on a hi-traffic transactional table
> - one ("some_id") high cardinality
> - and one ("yes_no") low cardinality
>
> You use both columns in SQL - "some_id" is used in JOIN and "yes_no" as a
> predicate

In the same SQL, or in separate SQLs?

> Would you create normal index on BOTH , just "some_id" or a composite
> indice on "some_id" + "yes_no" ?

I generally wouldn't bother with a single column index on "yes_no". I'd make one on (some_id,yes_no) and forget it. If it forces itself back into your attention due to performance issues, then I'd look at explain plans.

Xho

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