SYSAUX表空间做为SYSTEM表空间的辅助表空间，主要存放EM相关的内容以及表统计信息，AWR快照，审计信息等，而假设SYSAUX表空间在默认条件下你假设不做不论什么配置，随着时间的推移。会膨胀的越来越大。

经过几次的不断扩展添加SYSAUX表空间，眼下已经20G了，所以现是考虑减肥的时候了。

1. 查看表空间使用

SQL>

Select Tablespace_Name,

Sum_m,

Max_m,

Count_Blocks Free_Blk_Cnt,

Sum_Free_m,

To_Char(100 * Sum_Free_m / Sum_m, '99.9999')|| '%' As Pct_Free,

100 - To_Char(100 * Sum_Free_m / Sum_m,'99.9999') || '%' As Pct_used

From (Select Tablespace_Name, Sum(Bytes) / 1024 / 1024 AsSum_m

From Dba_Data_Files

Group By Tablespace_Name)

Left Join

(Select Tablespace_Name As Fs_Ts_Name,

Max(Bytes) / 1024 / 1024 As Max_m,

Count(Blocks) As Count_Blocks,

Sum(Bytes / 1024 / 1024) As Sum_Free_m

From Dba_Free_Space

Group ByTablespace_Name)

On Tablespace_Name = Fs_Ts_Name

ORDER BY Sum_Free_m / Sum_m ;

TABLESPACE_NAME                     SUM_M      MAX_M FREE_BLK_CNT SUM_FREE_MPCT_FREE  PCT_USED

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

SYSAUX                              21652       1031           13     1032.5  4.7686% 95.2314%

NTICKET_DB                         235520       7798         4922      46894 19.9108% 80.0892%

NTICKET_INDEX                      112640       2418          764      25382 22.5337% 77.4663%

SYSTEM                               2798       1884            7  1916.125  68.4820% 31.518%

USERS                                   5     3.6875            1     3.6875 73.7500% 26.25%

PORTALMAIL                            200    168.125            2        170 85.0000% 15%

UNDOTBS2                            10265       3596          200 9936.8125  96.8028% 3.1972%

UNDOTBS3                            10265       3593          248       9983 97.2528% 2.7472%

UNDOTBS1                            24455       3968          184 24280.625  99.2870% .713%

STRATEGY                            20480       3968            6      20478 99.9902% .0098%

2. 查看SYSAUX表空间内各个分类项目占存储空间的比重。能够看到AWR快照占用了近20G左右的空间，统计信息为300M左右，同一时候数据库关闭了审计audit_trail，所以审计表aud$不占空间

SQL> col Item For a30

SQL> col "Space Used(GB)" For a10

SQL> col Schema For a20

SQL> col "MoveProcedure" For a200

SQL>

SQL> SELECT occupant_name"Item",

round(space_usage_kbytes/1024/1024,3)"Space Used (GB)",

schema_name "Schema",

move_procedure "MoveProcedure"

FROM v$sysaux_occupants

ORDER BY 2 Desc;

Item                           Space UsedSchema               Move Procedure

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

SM/AWR                             19.103 SYS

SM/OPTSTAT                          0.311 SYS

SM/ADVISOR                          0.248 SYS

XDB                                 0.124 XDB                 XDB.DBMS_XDB.MOVEXDB_TABLESPACE

SDO                                 0.073MDSYS                MDSYS.MOVE_SDO

EM                                  0.045SYSMAN              emd_maintenance.move_em_tblspc

XSOQHIST                            0.037 SYS                  DBMS_XSOQ.OlapiMoveProc

AO                                  0.037SYS                  DBMS_AW.MOVE_AWMETA

ORDIM/ORDDATA                       0.013 ORDDATA             ordsys.ord_admin.move_ordim_tblspc

LOGMNR                              0.013 SYSTEM               SYS.DBMS_LOGMNR_D.SET_TABLESPACE

AUDIT_TABLES                            0 SYS                  DBMS_AUDIT_MGMT.move_dbaudit_tables

3. 改动统计信息的保持时间。默觉得31天，这里改动为7天。过期的统计信息会自己主动被删除

SQL> selectdbms_stats.get_stats_history_retention from dual;

GET_STATS_HISTORY_RETENTION

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

31

SQL> exec dbms_stats.alter_stats_history_retention(15);

PL/SQL procedure successfullycompleted

SQL> selectdbms_stats.get_stats_history_retention from dual;

GET_STATS_HISTORY_RETENTION

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

15

4. 改动AWR快照的保存时间为7天(7*24*60),每小时收集一次，也能够通过EM界面查看和改动

--检查当前系统的保留时间为8天,1小时採样一次

SQL> select * fromdba_hist_wr_control;

DBID SNAP_INTERVAL                           RETENTION                               TOPNSQL

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

1494575446 +0000001:00:00.0                       +0000800:00:00.0                       DEFAULT

--

SQL>

begin

dbms_workload_repository.modify_snapshot_settings(

interval => 60,

retention => 10080,--分钟

topnsql => 100

);

end;

ORA-13541: 系统移动窗体基线大小 (691200)
大于保留时间 (604800)

ORA-06512: 在"SYS.DBMS_WORKLOAD_REPOSITORY", line 174

ORA-06512: 在"SYS.DBMS_WORKLOAD_REPOSITORY", line 222

ORA-06512: 在 line 2

这里 691200(8*24*60*60)。604800(7*24*60*60)都是以秒为单位的。

发现运行报错，由于当前系统移动窗体大于如今所设的时间窗体。

--查看系统的当前的MOVING_WINDOW_SIZE。

SQL> selectdbid,baseline_name,baseline_type,moving_window_size from dba_hist_baseline;

DBID BASELINE_NAME                             BASELINE_TYPEMOVING_WINDOW_SIZE

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

1494575446SYSTEM_MOVING_WINDOW                     MOVING_WINDOW                  8

--改动其大小为7，即7天。

SQL> execdbms_workload_repository.modify_baseline_window_size(7);

PL/SQL procedure successfullycompleted

--再次运行改动AWR快照的保存时间

SQL> execDBMS_WORKLOAD_REPOSITORY.MODIFY_SNAPSHOT_SETTINGS(interval=>60,retention=> 7*24*60 );

PL/SQL procedure successfullycompleted

注：当然也可通过EM进行改动AWR设置

5.删除AWR快照，再次查看SYSAUX表空间使用率。

--查询最最小和最大快照ID

SQL> selectmin(snap_id),max(snap_id) from dba_hist_snapshot;

MIN(SNAP_ID) MAX(SNAP_ID)

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

8188         8397

--删除最早的24个AWR快照，也就是最早的24小时的快照。

SQL> execdbms_workload_repository.drop_snapshot_range(low_snap_id =>8188,high_snap_id => 8188+24);

最后。再次查看表空间发现使用率已经减小。