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。