Skip to Main Content
Forums

SQL & PL/SQL

Announcement

For appeals, questions and feedback about Oracle Forums, please email oracle-forums-moderators_us@oracle.com. Technical questions should be asked in the appropriate category. Thank you!

Interested in getting your voice heard by members of the Developer Marketing team at Oracle? Check out this post for AppDev or this post for AI focus group information.

Bitmap index on number column x char column

HandersonJul 23 2013 — edited Jul 23 2013

Hi everyone.

is there some performance/access difference between a bitmap index on a number column and char(1) column? Both columns are not null with a default value.

My application has a querie like this:

select ass.column20,

         ass.column30

from table_a puc
inner join table_b ass
on ass.column1 = puc.column1
where pc.column_char = 'S'
and ass.column_char02 = 'P'

If I create a bitmap index on column "column_char", the access plan is not changed. But changing the column datatype to number(1) and obviously the values, the index is accessed and the cost decreases.

This table has 4.000.000 rows.

Is there a explanation for this behavior?

Oracle 11.2.0.2

SO: AIX

Thanks in advance.

Handerson

Comments

Processing
Locked Post
New comments cannot be posted to this locked post.

Post Details

Locked on Aug 20 2013
Added on Jul 23 2013
#column, #index, #on
7 comments
598 views