Explain Plan und DBMS_XPLAN

-

(für Oracle 10gR2)

Installation

sqlplus / as sysdba

drop table plan_table;

@?/rdbms/admin/utlxplan

create public synonym plan_table for plan_table;

grant all on plan_table to public;

Weitere Informationen zum Explain Plan (http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/ex_plan.htm#i26143) bzw. bei Tom Kyte (http://asktom.oracle.com/tkyte/article1/autotrace.html)

Plan Table per DBMS_XPLAN.DISPLAY anzeigen

1) explain plan Kommando für einen SELECT Befehl ausführen:

EXPLAIN PLAN FOR

SELECT * FROM emp e, dept d

WHERE e.deptno = d.deptno

AND e.ename='benoit';

2) Anzeigen per DBMS_XPLAN.DISPLAY Tabellenfunktion:

SET LINESIZE 130

SET PAGESIZE 0

SELECT * FROM table(DBMS_XPLAN.DISPLAY);

Ergebnis-Bsp:

Plan hash value: 3693697075

---------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |

---------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 57 | 6 (34)| 00:00:01 |

|* 1 | HASH JOIN | | 1 | 57 | 6 (34)| 00:00:01 |

|* 2 | TABLE ACCESS FULL| EMP | 1 | 37 | 3 (34)| 00:00:01 |

| 3 | TABLE ACCESS FULL| DEPT | 4 | 80 | 3 (34)| 00:00:01 |

---------------------------------------------------------------------------

Quelle: http://download-uk.oracle.com/docs/cd/B19306_01/appdev.102/b14258/d_xplan.htm

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