set autotrace on exp;
Run Some SQL!
It shows me the bottle necks in my SQL statement, where indexes might help, and give me a pretty accurate estimate on the time the statement will take to run. This is all done within a second for so.
Example output..
Elapsed: 00:00:00.01
Execution Plan
----------------------------------------------------------
Plan hash value: 1080733679
--------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 21 | 2 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | 21 | | |
| 2 | NESTED LOOPS | | 1 | 21 | 2 (0)| 00:00:01 |
|* 3 | TABLE ACCESS FULL| NG_FILES | 1 | 16 | 2 (0)| 00:00:01 |
|* 4 | INDEX UNIQUE SCAN| PK_NG_FILES_ID | 1 | 5 | 0 (0)| 00:00:01 |
--------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
3 - filter("DATE_FILE_RECEIVED">=TIMESTAMP' 2009-12-16 00:00:00' AND
"DATE_FILE_RECEIVED"<=TIMESTAMP' 2009-12-17 00:00:00')
4 - access("NG_FILE_ID"="NG_FILE_ID")
