Hi!

I'm in the proccess of tuning some sql queries. Is there some way I can hint ( /*+ */ ) oracle to skip using an index when executing a query?

/Mattias

You can use the FULL hint with the alias of the table whose index you want to ignore, e.g.
SELECT /*+ FULL(e) */ empno, ename
FROM emp e
WHERE deptno = 123;

Of course, it's only a hint so Oracle may choose to ignore it.

An alternative is to experiment with the optimizer_index_cost_adj parameter- see here:

http://technet.oracle.com/docs/produ...htm#REFRN10143

Did the trick. Great, thanks!

By rule - RBO uses the latest table statistics to prepare the execution plan for a query. If you delete the statistics for particular table, then the RBO will force FTS (no index use in this case).

There is a package DBMS_STATS which allows you to manipulate the statistics - export first, then delete then, then import back. Of course you can also gather them as well.


Hope that helps,

clio_usa - OCP - DBA