最近在测试redo log的抓取,发现有不少后台写入动作,干扰了测试。比如经常看到如下语句:
insert into sysman.mgmt_system_performance_log(... ...) values(... ...)
网上也有类似的东西,比如:10g Archive log files fill disk http://www.orafaq.com/forum/t/44973/2/。建议设置将参数“statistics_level”改成“BASIC”,目前用的是“TYPICAL”。
下面是这个参数的官方说明:
Property | Description |
---|---|
Parameter type | String |
Syntax | STATISTICS_LEVEL = { ALL | TYPICAL | BASIC } |
Default value | TYPICAL |
Modifiable | ALTER SESSION , ALTER SYSTEM |
STATISTICS_LEVEL
specifies the level of collection for database and operating system statistics. The Oracle Database collects these statistics for a variety of purposes, including making self-management decisions.
The default setting of TYPICAL
ensures collection of all major statistics required for database self-management functionality and provides best overall performance. The default value should be adequate for most environments.
When the STATISTICS_LEVEL
parameter is set to ALL
, additional statistics are added to the set of statistics collected with the TYPICAL
setting. The additional statistics are timed OS statistics and plan execution statistics.
Setting the STATISTICS_LEVEL
parameter to BASIC
disables the collection of many of the important statistics required by Oracle Database features and functionality, including:
Automatic Workload Repository (AWR) Snapshots
Automatic Database Diagnostic Monitor (ADDM)
All server-generated alerts
Automatic SGA Memory Management
Automatic optimizer statistics collection
Object level statistics
End to End Application Tracing (V$CLIENT_STATS
)
Database time distribution statistics (V$SESS_TIME_MODEL
and V$SYS_TIME_MODEL
)
Service level statistics
Buffer cache advisory
MTTR advisory
Shared pool sizing advisory
Segment level statistics
PGA Target advisory
Timed statistics
Monitoring of statistics
Note: Oracle strongly recommends that you do not disable these important features and functionality. |
When the STATISTICS_LEVEL
parameter is modified by ALTER SYSTEM
, all advisories or statistics are dynamically turned on or off, depending on the new value of STATISTICS_LEVEL
. When modified by ALTER SESSION
, the following advisories or statistics are turned on or off in the local session only. Their system-wide state is not changed:
Timed statistics
Timed OS statistics
Plan execution statistics
The V$STATISTICS_LEVEL
view displays information about the status of the statistics or advisories controlled by the STATISTICS_LEVEL
parameter. See "V$STATISTICS_LEVEL".
测试一下先。改了之后要重启。结果还引发了不能启动的问题,耽误了一些时间。
过一段时间,再重新观察一下。发现还在不停的写入: insert into sysman.mgmt_system_performance_log
看了一下schedule,然后disable,也不行。
exec dbms_scheduler.disable('GATHER_STATS_JOB');
exec dbms_scheduler.disable('AUTO_SPACE_ADVISOR_JOB');
exec dbms_scheduler.disable('PURGE_LOG');
exec dbms_scheduler.disable('EXFSYS.RLM$SCHDNEGACTION');
exec dbms_scheduler.disable('EXFSYS.RLM$EVTCLEANUP');
SQL> select owner, job_name, enabled, state from DBA_SCHEDULER_JOBS;
OWNER JOB_NAME ENABL STATE
------------------------------ ------------------------------ ----- ---------------
SYS AUTO_SPACE_ADVISOR_JOB FALSE DISABLED
SYS GATHER_STATS_JOB FALSE DISABLED
SYS FGR$AUTOPURGE_JOB FALSE DISABLED
SYS PURGE_LOG FALSE DISABLED
EXFSYS RLM$SCHDNEGACTION FALSE DISABLED
EXFSYS RLM$EVTCLEANUP FALSE DISABLED
6 rows selected.
SQL>
只好速度放快点,几个DML发出后,立马切换,保存。总算不多不少,刚刚好。
可是事情并没有搞定啊。先放一放,主要是分析log。回头有空,再研究一下后台的job。