AWR不能自动生成快照解决方法
问题描述：RAC归档满后，出现AWR不能自动生成快照。经原理应该是MMON HANG住导致，所以尝试重启MMON后问题解决。；
MMON HANG解决办法
1)重启一下mmon的刷新
alter system set "_swrf_mmon_flush"=false;
alter system set "_swrf_mmon_flush"=true;
2)或者，找到mmon进程杀掉，让数据库自动重启一个新的mmon进程，或者重启下实例。
ps -ef|grep mmon
kill -9 xxxxxx
Manageability Monitor Processes (MMON and MMNL)
The manageability monitor process
(MMON) performs many tasks related to the Automatic Workload Repository
(AWR). For example, MMON writes when a metric violates its threshold
value, taking snapshots, and capturing statistics value for recently
modified SQL objects.
The manageability monitor lite process
(MMNL) writes statistics from the Active Session History (ASH) buffer
in the SGA to disk. MMNL writes to disk when the ASH buffer is full.
See Also:
"Automatic Workload Repository (AWR)" and "Active Session History (ASH)"
AWR和ASH后台运行进程
AWR ==>MMON
ASH ==>MMNL
MMON负责执行与AWR相关的任务。包括收集数据库统计信息，收集AWR快照，启动各种自动维护作业JOB，生成超过阀值告警信息。
MMNL负责执行与ASH相关的任务。
###之前MOS 专家咨询的记录
1. Please provide the below script output on failed instance:<info.html>
conn / as sysdbaset pages 1000set num 20
alter session set nls_date_format='yyyy-mm-dd hh34:mi:ss';
alter session set nls_timestamp_format='yyyy-mm-dd hh34:mi:ss.ff';
alter session set nls_timestamp_tz_format='yyyy-mm-dd hh34:mi:ss.ff tzh:tzm';
set mark html onspool info.html
select * from (select t.*, rank() over(partition by dbid, instance_number order by begin_interval_time desc) r from dba_hist_snapshot t) where r < 100;
select * from wrm$_wr_control where dbid = (select dbid from v$database);
select * from gv$database;
select * from gv$thread;show parameter statistics_level
show parameter control_management_pack_accessspool off
exit
2. Provide the "awrinfo" script output on instance
3: <awrinfo.txt>
SQL> conn / as sysdbaSQL> @?/rdbms/admin/awrinfo.sql
3. Enable SQL tracing on MMON slaves to collect more information. (do this in all instances)
begin
dbms_monitor.serv_mod_act_trace_enable(service_name => 'SYS$BACKGROUND'
,module_name => 'MMON_SLAVE'
,action_name => 'Auto-Flush Slave Action'
,waits => true
,binds => true);
end;
/
begin
dbms_monitor.serv_mod_act_trace_enable(service_name => 'SYS$BACKGROUND',
module_name => 'MMON_SLAVE'
,action_name => 'Remote-Flush Slave Action',
waits => true,binds => true);
end;
/
Wait for 2 snapshots time then upload the MMON (xxxx_mmon_xxxx.trc) and the below mmon slave trace files.
egrep -l "Auto-Flush Slave Action|Remote-Flush Slave Action" *.trc | xargs tar -cvf - | gzip > trace.tar.gzls -l trace.tar.gzTo disable the tracing later,
use "dbms_monitor.serv_mod_act_trace_disable" instead. for example:
begin
dbms_monitor.serv_mod_act_trace_disable(service_name => 'SYS$BACKGROUND',
module_name => 'MMON_SLAVE',
action_name => 'Auto-Flush Slave Action');
end;
/
begin
dbms_monitor.serv_mod_act_trace_disable(service_name => 'SYS$BACKGROUND',
module_name => 'MMON_SLAVE',
action_name => 'Remote-Flush Slave Action');
end;
/
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