WEB开发网
开发学院数据库Oracle Oracle Redo log日志组故障分析 阅读

Oracle Redo log日志组故障分析

 2007-05-10 12:16:09 来源:WEB开发网   
核心提示:数据库平台:SunOS 5.8 Generic_108528-23 sun4u sparc SUNW,Ultra-Enterprise数据库版本:8.1.5.0.0数据库症状:数据库响应缓慢,应用请求无法返回,Oracle Redo log日志组故障分析,业务操作陷于停顿,此时需要DBA介入并进行问题诊断及故障处理,C

数据库平台:SunOS 5.8 Generic_108528-23 sun4u sparc SUNW,Ultra-Enterprise

数据库版本:8.1.5.0.0

数据库症状:数据库响应缓慢,应用请求无法返回,业务操作陷于停顿,此时需要DBA介入并进行问题诊断及故障处理。

1. 登录数据库进行检查

首先我们登录数据库,检查故障现象。

经过检查发现,数据块的所有重做日志组除current外都处于active状态:

oracle:/oracle/oracle8>sqlplus "/ as sysdba"
SQL*Plus: Release 8.1.5.0.0 - Production on Thu Jun 23 18:56:06 2005
(c) Copyright 1999 Oracle Corporation. All rights reserved.
Connected to:
Oracle8i Enterprise Edition Release 8.1.5.0.0 - Production
With the Partitioning and Java options
PL/SQL Release 8.1.5.0.0 - Production
SQL> select * from v$log;
GROUP#  THREAD# SEQUENCE#   BYTES  MEMBERS ARC STATUS      FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
     1     1   520403  31457280     1 NO ACTIVE       1.3861E+10 23-JUN-05
     2     1   520404  31457280     1 NO ACTIVE       1.3861E+10 23-JUN-05
     3     1   520405  31457280     1 NO ACTIVE       1.3861E+10 23-JUN-05
     4     1   520406  31457280     1 NO CURRENT       1.3861E+10 23-JUN-05
     5     1   520398  31457280     1 NO ACTIVE       1.3860E+10 23-JUN-05
     6     1   520399  31457280     1 NO ACTIVE       1.3860E+10 23-JUN-05
     7     1   520400 104857600     1 NO ACTIVE       1.3860E+10 23-JUN-05
     8     1   520401 104857600     1 NO ACTIVE       1.3860E+10 23-JUN-05
     9     1   520402 104857600     1 NO ACTIVE       1.3861E+10 23-JUN-05
9 rows selected.
SQL> /
GROUP#  THREAD# SEQUENCE#   BYTES  MEMBERS ARC STATUS      FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
     1     1   520403  31457280     1 NO ACTIVE       1.3861E+10 23-JUN-05
     2     1   520404  31457280     1 NO ACTIVE       1.3861E+10 23-JUN-05
     3     1   520405  31457280     1 NO ACTIVE       1.3861E+10 23-JUN-05
     4     1   520406  31457280     1 NO CURRENT       1.3861E+10 23-JUN-05
     5     1   520398  31457280     1 NO ACTIVE       1.3860E+10 23-JUN-05
     6     1   520399  31457280     1 NO ACTIVE       1.3860E+10 23-JUN-05
     7     1   520400 104857600     1 NO ACTIVE       1.3860E+10 23-JUN-05
     8     1   520401 104857600     1 NO ACTIVE       1.3860E+10 23-JUN-05
     9     1   520402 104857600     1 NO ACTIVE       1.3861E+10 23-JUN-05
9 rows selected.

我们知道,当数据库发生日志切换时(Log Switch),Oracle会触发一个检查点(Checkpoint),检查点进程(Checkpoint Process,CKPT)会通知DBWR(Database?Writer)进程去执行写操作。在日志文件所保护的处于Buffer cache中的脏数据(dirty buffer)未写回磁盘之前,日志文件不能被覆盖或重用。

1 2 3 4  下一页

Tags:Oracle Redo log

编辑录入:爽爽 [复制链接] [打 印]
赞助商链接