RE: Hint for using a nested loop for an in subquery

  • From: "Ken Naim" <kennaim@xxxxxxxxx>
  • To: "'Jonathan Lewis'" <jonathan@xxxxxxxxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 3 Nov 2006 16:27:08 -0500

Thanks, I have used in this query but I am still getting a hash join or a
filter instead of nested loops causing the query to run for minutes instead
of 285 milliseconds, so what I need is hint that will tell the query to run
nested loops against the in subquery?

thanks

-----Original Message-----
From: Jonathan Lewis [mailto:jonathan@xxxxxxxxxxxxxxxxxx] 
Sent: Friday, November 03, 2006 3:53 PM
To: kennaim@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: Hint for using a nested loop for an in subquery


If you want to execute the subquery first, the hint
you want is UNNEST in the subquery.

Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com

Author: Cost Based Oracle: Fundamentals
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html


----- Original Message ----- 
From: "Ken Naim" <kennaim@xxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Friday, November 03, 2006 8:10 PM
Subject: Hint for using a nested loop for an in subquery


>I have used a hint in the past to force a query to use a nested loop join
> for a sub query however the name of the hint escapes me. I have googled
for
> it unsuccessfully. Anyone remember it offhand?
>
> Query looks like
>
> Select something
> From  table1
> Where somethingelse in (select somethingelse from table2 where
> somethingelse2 between x and y)
>
> The ideal plan would evaluate the subquery first then use nested loops
> against an index belonging to table1. I have tried using the no_unnest,
> various index and use_nl hints unsuccessfully.
>
> Thanks,
> Ken
>


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