Обсуждение: Question about indexes

On Mon, 15 Nov 2004 11:38:29 +0100, Stefano Bonnin
<stefano.bonnin@comai.to> wrote:
>
> Only a simple question
>
> I have a table with
>
>     primarykey(field1,field2,field3)
>
> and I want to execure a query like
>
>         select * from my_table where field1 = some_value
>
> if I define an index on field1, I increase the query performace or not?

You increase it a bit.  Anyway its not worth the hassle, as increase is
rather marginal, and having two indexes lessens the chance that
they'll be served from cache.

If you're not sure yet, just make some tests. :)

   Regards,
       Dawid