SQL> select distinct employee_id,first_name from test1;
107 rows selected.
Execution Plan
----------------------------------------------------------
Plan hash value: 255531131
------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 6647K| 158M| | 67481 (1)| 00:13:30 |
| 1 | HASH UNIQUE | | 6647K| 158M| 229M| 67481 (1)| 00:13:30 |
| 2 | TABLE ACCESS FULL| TEST1 | 6647K| 158M| | 19570 (1)| 00:03:55 |
------------------------------------------------------------------------------------
Note
-----
- dynamic sampling used for this statement (level=2)
Statistics
----------------------------------------------------------
4 recursive calls
0 db block gets
142133 consistent gets
71297 physical reads
0 redo size
2749 bytes sent via SQL*Net to client
496 bytes received via SQL*Net from client
9 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
107 rows processed
SQL> select employee_id,first_name from test1 group by employee_id,first_name;
107 rows selected.
Execution Plan
----------------------------------------------------------
Plan hash value: 1431305903
----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 6647K| 158M| 19781 (2)| 00:03:58 |
| 1 | HASH GROUP BY | | 6647K| 158M| 19781 (2)| 00:03:58 |
| 2 | TABLE ACCESS FULL| TEST1 | 6647K| 158M| 19570 (1)| 00:03:55 |
----------------------------------------------------------------------------
Note
-----
- dynamic sampling used for this statement (level=2)
Statistics
----------------------------------------------------------
4 recursive calls
0 db block gets
142133 consistent gets
71297 physical reads
0 redo size
2749 bytes sent via SQL*Net to client
496 bytes received via SQL*Net from client
9 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
107 rows processed
