Re: Do I need an Index?

On 11 Aug 2005 13:55:45 -0700, "mike" <hillmw_at_charter.net> wrote:

>Sybrand,
>
>I am not being insensitive about you name at all. Sorry if you were
>offended. I do appreciate your help.
>
>I made this change "alter session set optimizer_mode = first_rows"
>after the user logs-in, but I didn't see any noticeable help with the
>query.
>
>How do I include these hints when running my query
>--> generic) hint /*+ FIRST_ROWS */.
>
>How do I:
>--> "verify the optimizer_index_cost_adj and optimizer_index_caching."
>
>Thanks
>
>Mike

1 How did you verify you didn't get any noticeable help? Did you run EXPLAIN PLAN? Did you issue set autotrace on explain stat? Or did you just look on your watch?
2 Hints need to be included after the SELECT keyword. SELECT /*+ FIRST_ROWS */ rest of statement... 3 show parameter optimizer_index_cost_adj etc or just show parameter opt (implicit wildcard operation)

You are aware of http://tahiti.oracle.com and the Performance tuning manual (and lots of others) of that site?

--
Sybrand Bakker, Senior Oracle DBA