案例:AWR 手工创建快照失败,SYSAUX 表空间剩余不足处理
版本: Oracle 11.2.0.4 RAC
问题现象:AWR 手工创建快照失败,SYSAUX 表空间剩余不足。
查看 SYSAUX 表空间的段大小,按大小排序:
- select segment_name, sum(bytes) / 1024 / 1024
- from dba_segments
- where tablespace_name = 'SYSAUX'
- group by segment_name
- order by 2;
最大的结果列表:
- SEGMENT_NAME SUM(BYTES)/1024/1024
- ------------------------------ --------------------
- WRH$_SYSMETRIC_HISTORY_INDEX 80
- WRH$_DLM_MISC_PK 80.0625
- WRH$_DLM_MISC 96.0625
- WRH$_EVENT_HISTOGRAM 688.0625
- WRH$_EVENT_HISTOGRAM_PK 1008.0625
- WRH$_ACTIVE_SESSION_HISTORY_PK 3016.0625
- WRH$_ACTIVE_SESSION_HISTORY 22373.0625
- 4462 rows selected.
发现最大的对象是 WRH$_ACTIVE_SESSION_HISTORY,这里占了 22G 的大小,另外其对应的主键索引也占了 3G。
查看 AWR 列表:
- @ ? /rdbms/admin / awrrpt
AWR 快照列表是空
Listing all Completed Snapshots
尝试手工创建快照也会失败,明确提示是 SYSAUX 表空间剩余不足,无法扩展。
- exec DBMS_WORKLOAD_REPOSITORY.create_snapshot();
根据 MOS 文档 WRH$_ACTIVE_SESSION_HISTORY Does Not Get Purged Based Upon the Retention Policy (文档 ID 387914.1)
查询表空间使用率:
- set lines 400 pages 999
- select TABLESPACE_NAME,(TABLESPACE_SIZE-USED_SPACE)*8/1024/1024 free_space, USED_SPACE*8/1024/1024 USED_SPACE,TABLESPACE_SIZE*8/1024/1024 TABLESPACE_SIZE,USED_PERCENT from DBA_TABLESPACE_USAGE_METRICS order by 5 ;
SYSAUX 3.60882568 28.3911591 31.9999847 88.7224144
查询 WRH$_ACTIVE_SESSION_HISTORY 的分区信息:
- SELECT owner,
- segment_name,
- partition_name,
- segment_type,
- bytes/1024/1024/1024 Size_GB
- FROM dba_segments
- WHERE segment_name='WRH$_ACTIVE_SESSION_HISTORY';
结果如下:
- OWNER SEGMENT_NAME PARTITION_NAME SEGMENT_TYPE SIZE_GB
- ------------------------------ ------------------------------ ------------------------------ ------------------ ----------
- SYS WRH$_ACTIVE_SESSION_HISTORY WRH$_ACTIVE_1154052622_0 TABLE PARTITION 21.7900391
- SYS WRH$_ACTIVE_SESSION_HISTORY WRH$_ACTIVE_SES_MXDB_MXSN TABLE PARTITION .000061035
根据 MOS 的说明操作:
- alter session set "_swrf_test_action" = 72;
经过这一步之后,发现分割出一个分区,而且实际发现 SYSAUX 表空间释放出 3G 的空间,这里思考一下,分割分区并不会导致空间下降,推测有可能是分割的操作触发了自动删除的条件。
结果如下 (多了一个分区):
- OWNER SEGMENT_NAME PARTITION_NAME SEGMENT_TYPE SIZE_GB
- ------------------------------ ------------------------------ ------------------------------ ------------------ ----------
- SYS WRH$_ACTIVE_SESSION_HISTORY WRH$_ACTIVE_1154052622_0 TABLE PARTITION 21.7900391
- SYS WRH$_ACTIVE_SESSION_HISTORY WRH$_ACTIVE_1154052622_5093 TABLE PARTITION .05859375
- SYS WRH$_ACTIVE_SESSION_HISTORY WRH$_ACTIVE_SES_MXDB_MXSN TABLE PARTITION .000061035
此时,根据 MOS 文档说明,执行:
- set serveroutput on
- declare
- CURSOR cur_part IS
- SELECT partition_name from dba_tab_partitions
- WHERE table_name = 'WRH$_ACTIVE_SESSION_HISTORY';
- query1 varchar2(200);
- query2 varchar2(200);
- TYPE partrec IS RECORD (snapid number, dbid number);
- TYPE partlist IS TABLE OF partrec;
- Outlist partlist;
- begin
- dbms_output.put_line('PARTITION NAME SNAP_ID DBID');
- dbms_output.put_line('--------------------------- ------- ----------');
- for part in cur_part loop
- query1 := 'select min(snap_id), dbid from sys.WRH$_ACTIVE_SESSION_HISTORY partition ('||part.partition_name||') group by dbid';
- execute immediate query1 bulk collect into OutList;
- if OutList.count > 0 then
- for i in OutList.first..OutList.last loop
- dbms_output.put_line(part.partition_name||' Min '||OutList(i).snapid||' '||OutList(i).dbid);
- end loop;
- end if;
- query2 := 'select max(snap_id), dbid from sys.WRH$_ACTIVE_SESSION_HISTORY partition ('||part.partition_name||') group by dbid';
- execute immediate query2 bulk collect into OutList;
- if OutList.count > 0 then
- for i in OutList.first..OutList.last loop
- dbms_output.put_line(part.partition_name||' Max '||OutList(i).snapid||' '||OutList(i).dbid);
- dbms_output.put_line('---');
- end loop;
- end if;
- end loop;
- end;
- /
得到结果如下:
- PARTITION NAME SNAP_ID DBID
- --------------------------- ------- ----------
- WRH$_ACTIVE_1154052622_5093 Min 5093 1154052622
- WRH$_ACTIVE_1154052622_5093 Max 5210 1154052622
- ---
- WRH$_ACTIVE_1154052622_0 Min 1 1154052622
- WRH$_ACTIVE_1154052622_0 Max 5092 1154052622
- ---
MOS 上清空历史分区的方法:
- DBMS_WORKLOAD_REPOSITORY.DROP_SNAPSHOT_RANGE(
- low_snap_id IN NUMBER,
- high_snap_id IN NUMBER
- dbid IN NUMBER DEFAULT NULL);
实际如果执行就是:
- exec DBMS_WORKLOAD_REPOSITORY.DROP_SNAPSHOT_RANGE(1,5092);
- --如果不是本地的dbid,那就第三个参数值填上对应dbid的参数即可,当然这里不需要加:
- exec DBMS_WORKLOAD_REPOSITORY.DROP_SNAPSHOT_RANGE(1,5092,1154052622);
但经过测试上一种 MOS 提到的方法比较慢,而且不立即释放空间。
所以如果想立即释放表空间,可以考虑评估直接 truncate 此表的对应分区(反复确认好后再操作):
截断分区前查询表空间使用率:
- set lines 400 pages 999
- select TABLESPACE_NAME,(TABLESPACE_SIZE-USED_SPACE)*8/1024/1024 free_space, USED_SPACE*8/1024/1024 USED_SPACE,TABLESPACE_SIZE*8/1024/1024 TABLESPACE_SIZE,USED_PERCENT from DBA_TABLESPACE_USAGE_METRICS order by 5 ;
- SYSAUX 3.60784912 28.3921356 31.9999847 88.7254661
truncate 历史分区 WRH$_ACTIVE_1154052622_0
- SQL > alter table WRH$_ACTIVE_SESSION_HISTORY truncate partition WRH$_ACTIVE_1154052622_0;
- Table truncated.
再次查询表空间使用率 (已发现 SYSAUX 表空间使用率下降成功):
- SYSAUX 28.3323364 3.66764832 31.9999847 11.4614065
再次查询 WRH$_ACTIVE_SESSION_HISTORY 的分区信息:
- OWNER SEGMENT_NAME PARTITION_NAME SEGMENT_TYPE SIZE_GB
- ------------------------------ ------------------------------ ------------------------------ ------------------ ----------
- SYS WRH$_ACTIVE_SESSION_HISTORY WRH$_ACTIVE_1154052622_5093 TABLE PARTITION .059570313
- SYS WRH$_ACTIVE_SESSION_HISTORY WRH$_ACTIVE_SES_MXDB_MXSN TABLE PARTITION .000061035
- SYS WRH$_ACTIVE_SESSION_HISTORY WRH$_ACTIVE_1154052622_0 TABLE PARTITION .000061035
至此,完成 WRH$_ACTIVE_SESSION_HISTORY 的分区清理,SYSAUX 表空间得到释放。
来源: http://www.linuxidc.com/Linux/2017-12/149979.htm