Re: optimizer won't pick bitmap index

Mikael

Can you provide more information such as the exact SQL and the explain plans before and after creating index and adding hint ?

To provide some pointers to be going on with: -

1. Be careful to use the alias as the table_name in the hint if you have aliased a table
2. Make sure the names are correct as Oracle will ignore invalid hints without raising an error
3. Make sure you don't have incomplete statistics on the table - either have none and fully hint the SQL or have complete stats as this often complicates matters.

Andy

"Mikael Kruse" <mikael.kruse_at_ehs.ericsson.se> wrote in message news:ai3l3k$gva$1_at_newstoo.ericsson.se...
> Hi,
> I have a query taking some time and thought I'd test if it goes quicker
> using a bitmap index. So I created the bitmap index and now I'm trying to
> give hints to the optimizer to make it use the index, but I do not
> succeed...
> Running Oracle 8.0.6 on HP-UX, optimizer mode=RULE and changing to
> cost-based on system or session level is not an option. My method has been
> to simply give a hint:
> select /*+ index(table_name index_name) */ column1, column2....
> but as mentioned it doesn't work. I've also tried giving two hints:
> select /*+ all_rows index(table_name index_name) */ column1, column2....
> to make the optimizer switch to cost-based for this query and then use
> bitmap index but it was no good.
> If anyone can help me I would be really grateful...
>
> /Mikael
>
>
Received on Mon Jul 29 2002 - 10:30:00 CDT