本篇内容介绍了“oracle快照不自动创建导致没办法收集awr报告的原因和解决方法”的有关知识,在实际案例的操作过程中,不少人都会遇到这样的困境,接下来就让小编带领大家学习一下如何处理这些情况吧!希望大家仔细阅读,能够学有所成!

今天发现客户oracle rac环境一节点不能自动创建快照,导致没有办法收集awr报告,只能手工创建快照,经过信息排除,发现一节点比二节点少了一些进程,发现一节点没有mmon和mmnl进程,这两进程就是自动创建快照的进程,这连个进程是oracle的非核心进程,可以kill掉,杀掉进程oracle会自动启动进程,并且自动维护。但客户这里的这两个进程是彻底的死掉了。在oracle mos中查找解决的原因。

关于MMON和MMNL后台进程的MOS Document:

APPLIES TO:

Oracle Database - Enterprise Edition - Version 11.2.0.4 to 11.2.0.4 [Release 11.2]
Information in this document applies to any platform.

SYMPTOMS

Due to other reasons, the MMON process died and subsequent AWR reports are therefore not getting generated.

The MMON process should automatically be respawned but it is not.

CAUSE

MMON/MMNL not being respawned or recreated is due to:

unpublished bug: Bug 19565533 - MMON/MMNL CAN NOT BE AUTOMATICALLY RESTARTED AFTER KILLED

The issue only occurs on 11.2.0.4 and is a regression of the fix for

Apply interimAs a workaround, you can respawn the MMON process by next methods:
Restart the database instance

- OR -
Set the instance to "restricted session" mode and then bring it back to normal mode using following commands as SYSDBA:
  
alter system enable restricted session;
alter system disable restricted session;

原因:是bug所导致的mmon和mmnl进程死掉

解决办法:

1、重启实例

2、不需要重启实例,将数据库设置成restricted session模式

alter system enable restricted session;
alter system disable restricted session;

设置restricted session模式,对dba权限没有影响,普通用户是无法连接数据库,需要授予restricted session权限才能连接数据库,普通用户现有的链接不会有影响。