Oracle Read - Oracle Blogs Aggregator

Bitmap indexes must never be used in OLTP systems - in other words, for tables where many insert/update/delete are done. Every insert/delete/update on such table with bitmap index locks corresponding index key until commit or rollback is performed.

Take a look on the following example.  I will create a table with a single column - gender - and will create a bitmap index on this column.
SQL> create table t1(gender varchar2(1));
Table created.
SQL> create bitmap index idx1 on t1(gender);
Index created.
SQL> insert into t1 values(’M’);
1 row created.
SQL> insert into t1 values(’M’);
1 row created.
SQL> insert into t1 values(’F’);
1 row created.
SQL> insert into t1 values(’F’);
1 row

…click on the title to read the full article…