Remove all advisory reports (ADM).

[REMI@DB01.REMIDIAN.COM]
SQL> select 'exec dbms_advisor.delete_task(''' || TASK_NAME || ''' )' from dba_advisor_tasks;
 
'EXECDBMS_ADVISOR.DELETE_TASK('''||TASK_NAME||''')'
----------------------------------------------------------------
exec dbms_advisor.delete_task('SYS_AUTO_SPCADV_1300592007' )
exec dbms_advisor.delete_task('SYS_AUTO_SPCADV_2700592007' )
exec dbms_advisor.delete_task('SYS_AUTO_SPCADV_2220592007' )
exec dbms_advisor.delete_task('ADDM:1488676071_1_33108' )
exec dbms_advisor.delete_task('ADDM:1488676071_1_33113' )
 
[REMI@DB01.REMIDIAN.COM]
SQL>

I still tend to use this old fashioned ‘set autot trace exp’

[REMI@DB01.REMIDIAN.COM]
SQL> set autotrace trace exp
[REMI@DB01.REMIDIAN.COM]
SQL> select * from dual;
 
Execution Plan
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=ALL_ROWS (Cost=2 Card=1 Bytes=2)
   1    0   TABLE ACCESS (FULL) OF 'DUAL' (TABLE) (Cost=2 Card=1 Bytes
          =2)
 

While in 10g the explain plan is pretty awseome – dbms_xplan package

[REMI@DB01.REMIDIAN.COM]
SQL> explain plan for select * from dual;
 
Explained.
 
[REMI@DB01.REMIDIAN.COM]
SQL> select * from table(dbms_xplan.display());
PLAN_TABLE_OUTPUT
----------------------------------------------------------------------------
Plan hash value: 3543395131
 
--------------------------------------------------------------------------
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------
|   0 | SELECT STATEMENT  |      |     1 |     2 |     2   (0)| 00:00:01 |
|   1 |  TABLE ACCESS FULL| DUAL |     1 |     2 |     2   (0)| 00:00:01 |
--------------------------------------------------------------------------
 
8 rows selected.
 
[REMI@DB01.REMIDIAN.COM]
SQL> 

[REMI@DB01.REMIDIAN.COM]
SQL> create view v_demo as select * from dual;
 
View created.
 
[REMI@DB01.REMIDIAN.COM]
SQL> create synonym s_demo for remi.v_demo;
 
Synonym created.
 
[REMI@DB01.REMIDIAN.COM]
SQL> select object_name, object_type, status
  2    from all_objects
  3   where object_name in ('V_DEMO', 'S_DEMO');
OBJECT_NAME                      OBJECT_TYPE    STATUS
-------------------------------- -------------- ---------------
S_DEMO                           SYNONYM        VALID
V_DEMO                           VIEW           VALID
 
[REMI@DB01.REMIDIAN.COM]
SQL> create or replace view v_demo as select * from dual;
 
View created.
 
[REMI@DB01.REMIDIAN.COM]
SQL> select object_name,
  2         object_type,
  3         status,
  4         to_char( last_ddl_time, 'yyyy-mm-dd:hh24:mi:ss') last_ddl_time,
  5         timestamp
  6    from all_objects
  7   where object_name in ('V_DEMO', 'S_DEMO');
OBJECT_NAME  OBJECT_TYPE     STATUS          LAST_DDL_TIME       TIMESTAMP
------------ --------------- --------------- ------------------- -------------------
S_DEMO       SYNONYM         VALID           2006-08-30:22:09:30 2006-08-30:22:09:30
V_DEMO       VIEW            VALID           2006-08-30:22:09:30 2006-08-30:22:09:30

Now ‘touch’ the synonym, oracle compiles the synonym and marks it valid again. (You will recieve no error.)

 
[REMI@DB01.REMIDIAN.COM]
SQL> select * from s_demo where 1 = 2 ;
 
no rows selected
 
[REMI@DB01.REMIDIAN.COM]
SQL> select object_name,
  2         object_type,
  3         status,
  4         to_char( last_ddl_time, 'yyyy-mm-dd:hh24:mi:ss') last_ddl_time,
  5         timestamp
  6    from all_objects
  7   where object_name in ('V_DEMO', 'S_DEMO');
OBJECT_NAME  OBJECT_TYPE     STATUS          LAST_DDL_TIME       TIMESTAMP
------------ --------------- --------------- ------------------- -------------------
S_DEMO       SYNONYM         INVALID         2006-08-30:22:09:35 2006-08-30:22:09:35
V_DEMO       VIEW            VALID           2006-08-30:22:09:30 2006-08-30:22:09:30
 

Purge Command in pre 10G SQL*Plus release

Whenever you want to issue the ‘purge’ command in any pre 10G SQL*Plus client you will notice that SQL*Plus denies to send your command to the server and it will raise an ‘SP2-0734′ error. You can easiliy overcome this by making use of dynamic sql (or just upgrade your client of course).

[REMI@DB01.REMIDIAN.COM]
SQL> create table demo(k int);
 
Table created.
 
[REMI@DB01.REMIDIAN.COM]
SQL> drop table demo;
 
Table dropped.
 
[REMI@DB01.REMIDIAN.COM]
SQL> select * from cat;
TABLE_NAME                     TABLE_TYPE
------------------------------ -----------
BIN$HE/mKBNyRajgRAADuhSWrA==$0 TABLE
 
[REMI@DB01.REMIDIAN.COM]
SQL> 
[REMI@DB01.REMIDIAN.COM]
SQL> drop table "BIN$HE/mKBNyRajgRAADuhSWrA==$0";
drop table "BIN$HE/mKBNyRajgRAADuhSWrA==$0"
           *
ERROR at line 1:
ORA-38301: can not perform DDL/DML over objects in Recycle Bin
 
[REMI@DB01.REMIDIAN.COM]
SQL> purge user_recyclebin;
SP2-0734: unknown command beginning "purge user..." - rest of line ignored.
[REMI@DB01.REMIDIAN.COM]
SQL> prompt &_SQLPLUS_RELEASE
902000700

Solution is beautiful in it’s simplicity, use dynamic sql and off you go.

Purge recycle bin with a pre 10G SQL*Plus client

[REMI@DB01.REMIDIAN.COM]
SQL> begin 
  2    execute immediate 'purge user_recyclebin';
  3  end;
  4  /
 
PL/SQL procedure successfully completed.
 
[REMI@DB01.REMIDIAN.COM]
SQL> select * from cat;
 
no rows selected

Interval

Some queries;

Listing below shows one snapshot is taken every 20 minutes, the snapshot is stored for a week (7 days).

[SYSTEM@DB01.REMIDIAN.COM]
SQL> select snap_interval, retention
  2  from   dba_hist_wr_control
  3  /
 
SNAP_INTERVAL                    RETENTION
-------------------------------- ------------------------------
+00000 00:20:00.0                +00007 00:00:00.0

Alter the interval to once every hour and store it for a month (31 days);

[SYSTEM@DB01.REMIDIAN.COM]
SQL> begin
  2     dbms_workload_repository.modify_snapshot_settings
  3        ( interval   => 60
  4        , retention  => 31 * 24 * 60);
  5  end;
  6  /
 
PL/SQL procedure successfully completed.
 
[SYSTEM@DB01.REMIDIAN.COM]
SQL> select snap_interval, retention
  2  from   dba_hist_wr_control
  3  /
 
SNAP_INTERVAL                    RETENTION
-------------------------------- ------------------------------
+00000 01:00:00.0                +00031 00:00:00.0
 

History

Five latest snapshots

[SYSTEM@DB01.REMIDIAN.COM]
SQL> select *
  2  from   (
  3         select snap_id, startup_time, begin_interval_time, end_interval_time
  4         from   dba_hist_snapshot
  5         order by snap_id
  6         )
  7  where rownum < 6
  8  /
 
   SNAP_ID STARTUP_TIME              BEGIN_INTERVAL_TIME       END_INTERVAL_TIME
---------- ------------------------- ------------------------- -------------------------
        23 30-JUN-06 05.59.11.000 PM 30-JUN-06 05.59.11.000 PM 30-JUN-06 06.02.04.711 PM
        24 30-JUN-06 05.59.11.000 PM 30-JUN-06 06.02.04.711 PM 30-JUN-06 07.00.29.599 PM
        25 30-JUN-06 05.59.11.000 PM 30-JUN-06 07.00.29.599 PM 30-JUN-06 08.00.33.577 PM
        26 30-JUN-06 05.59.11.000 PM 30-JUN-06 08.00.33.577 PM 30-JUN-06 09.00.39.837 PM
        27 30-JUN-06 05.59.11.000 PM 30-JUN-06 09.00.39.837 PM 30-JUN-06 10.00.38.742 PM
 
[SYSTEM@DB01.REMIDIAN.COM]
SQL> exec dbms_workload_repository.create_snapshot;
 
PL/SQL procedure successfully completed.
 
[SYSTEM@DB01.REMIDIAN.COM]
SQL> select *
  2  from   (
  3         select snap_id, startup_time, begin_interval_time, end_interval_time
  4         from   dba_hist_snapshot
  5         order by snap_id
  6         )
  7  where rownum < 6
  8  /
 
   SNAP_ID STARTUP_TIME              BEGIN_INTERVAL_TIME       END_INTERVAL_TIME
---------- ------------------------- ------------------------- -------------------------
        23 30-JUN-06 05.59.11.000 PM 30-JUN-06 05.59.11.000 PM 30-JUN-06 06.02.04.711 PM
        24 30-JUN-06 05.59.11.000 PM 30-JUN-06 06.02.04.711 PM 30-JUN-06 07.00.29.599 PM
        25 30-JUN-06 05.59.11.000 PM 30-JUN-06 07.00.29.599 PM 30-JUN-06 08.00.33.577 PM
        26 30-JUN-06 05.59.11.000 PM 30-JUN-06 08.00.33.577 PM 30-JUN-06 09.00.39.837 PM
        27 30-JUN-06 05.59.11.000 PM 30-JUN-06 09.00.39.837 PM 30-JUN-06 10.00.38.742 PM
 

@see

• Database Performance Tuning Guide – 5 Automatic Performance Statistics
• Database PL/SQL Packages and Types Reference – DBMS_WORKLOAD_REPOSITORY

• http://www.oracle.com/technology/pub/articles/10gdba/week6_10gdba.html
• http://www.oracle-base.com/articles/10g/AutomaticWorkloadRepository10g.php