Re: Bitmap index and perfomance

Thanks.

I think before that bitmap indexes doesn't work without statistics, but they work.
But I receive bad results with other queries without statistics ( tuned with cost-based).

When I set parameter b_tree_bitmap_plans=true choose right plan, but I don't know
how this parameter have influence on other queries (I can't test all of these).

Is there another way ?

Alexander

Olivier Bercovitz wrote:

> Hello Alexander,
>
> just some idea to test
> 1) try without cost-based statistics, delete all statistics on table
> and index (with analyze ....delete statistics)
> and optimizer_mode=choose
> 2) another way is to force the plan with hint (not pretty but it's
> work!)
>
> Try first without statistics.
>
> Hope this helps.
>
> Regards. Olivier
>
> Alexander wrote:
>
> > Hi,
> > I have performance problem with tables that have at least one bitmap
> > index.
> > Queries like "SELECT * FROM table1 WHERE status 'A' " work propertly,
> > but if I want
> > "SELECT * FROM table1 ORDER BY id" oracle choose :
> > SELECT STATEMENT
> > SORT (Order By)
> > TABLE ACCESS BY ROWID
> > table1
> > BITMAP CONVERSION (TO ROWIDS)
> > BITMAP INDEX (FULL SCAN)
> > i_table1_status
> > and select works 5-6 min ( 60000 rows).
> > Oracle: 7.3.3.4. I tried on SUN and HP.
> > Optimizer mode : first_rows
> > v733_plans_enabled = true
> >
> > Someone knows what the problem might be?
> > Thanks in advance.
> > Alexander
> > aryabikov_at_dialogbank.com
Received on Tue Mar 24 1998 - 00:00:00 CST