Materialized View Example

Hi,

I didn't get chance to use Materialized views in my job yet but to sharpen my skills for future, I was working on it.

I created a table EMP from HR.EMPLOYEES table. EMPLOYEES table has 107 rows in it. I copied it to EMP table multiple times and total number of rows in it are 54784 now.

After setting SET TIMING ON

1. First, I ran SELECT statement on EMP table without creating Materialized View and
2. then I create a Materialized View called EMP_MV and
3. I reran the SELECT statement both on EMP table and EMP_MV view.

Timing came almost same in both cased (with and without Materialize view).

Can somebody pls show me a scenario, which can really make me believe that Materialize Views are really worth to use?

Thanks in advance...!! Will appreciate your response..!!!

--------------------------------------------------------------------------------------------------------------------------------------------
SQL> select count(1) from emp;

COUNT(1)
----------
54784
--------------------------------------------------------------------------------------------------------------------------------------------

Execution Plan
----------------------------------------------------------
Plan hash value: 3956160932

--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 56469 | 7334K| 141 (1)| 00:00:02 |
| 1 | TABLE ACCESS FULL| EMP | 56469 | 7334K| 141 (1)| 00:00:02 |
--------------------------------------------------------------------------

54784 rows selected.

Elapsed: 00:02:19.61
--------------------------------------------------------------------------------------------------------------------------------------------
Execution Plan
----------------------------------------------------------
Plan hash value: 1199708657

---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 44487 | 5778K| 127 (1)| 00:00:02 |
| 1 | MAT_VIEW REWRITE ACCESS FULL| EMP_MV | 44487 | 5778K| 127 (1)| 00:00:02 |
---------------------------------------------------------------------------------------

54784 rows selected.

Elapsed: 00:02:19.61

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