Explain Plan

http://www.orafaq.com/wiki/Explain_Plan

http://www.psoug.org/reference/trace_analyzer.html

SQL> EXPLAIN PLAN FOR select * from dept where deptno = 40;
Explained.


SQL> set linesize 132
SQL> SELECT * FROM TABLE(dbms_xplan.display);

PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------
Plan hash value: 2852011669
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 20 | 1 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| DEPT | 1 | 20 | 1 (0)| 00:00:01 |
|* 2 | INDEX UNIQUE SCAN | PK_DEPT | 1 | | 0 (0)| 00:00:01 |
---------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

2 - access("DEPTNO"=40)

14 rows selected.



==============================================

SQL> SET AUTOTRACE ON
SQL> select * from dept where deptno = 40;

DEPTNO DNAME LOC
---------- -------------- -------------
40 OPERATIONS BOSTON

Execution Plan
----------------------------------------------------------
Plan hash value: 2852011669

---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 20 | 1 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| DEPT | 1 | 20 | 1 (0)| 00:00:01 |
|* 2 | INDEX UNIQUE SCAN | PK_DEPT | 1 | | 0 (0)| 00:00:01 |
---------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

2 - access("DEPTNO"=40)

Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
2 consistent gets
0 physical reads
0 redo size
443 bytes sent via SQL*Net to client
374 bytes received via SQL*Net from client
1 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed