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Relation - Bitmap Indexes in Oracle
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BITMAP CONVERSION TO ROWIDS
nico@ORCL>select * from emp where job = 'CLERK' or job = 'MANAGER';
Execution Plan
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| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
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| 0 | SELECT STATEMENT | | 7 | 609 | 2 (0)| 00:00:01 |
| 1 | INLIST ITERATOR | | | | | |
| 2 | TABLE ACCESS BY INDEX ROWID | EMP | 7 | 609 | 2 (0)| 00:00:01 |
| 3 | BITMAP CONVERSION TO ROWIDS| | | | | | <-------- Here
|* 4 | BITMAP INDEX SINGLE VALUE | JOB_IDX | | | | |
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We need for this query to get to the table. Here, Oracle will apply a function to turn the fact that i'th bit is on in a bitmap, into a rowid that can be used to access the table.