场景:
SQL> alter system archive log current;
alter system archive log current
*
第 1 行出现错误:
ORA-16014: 日志 2 sequence# 34 未归档, 没有可用的目的地
ORA-00312: 联机日志 2 线程 1: ‘+DATA_DG/orcl/onlinelog/group_2.258.885126161‘
ORA-00312: 联机日志 2 线程 1: ‘/orabak/clog/orcl02.log‘
环境是个人的实验环境。
排查:
切日志时发现该日志无法归档了。然后进行下面排查
1. 检查日志格式。确定日志格式log_archive_format正确
2. 检查日志归档文件夹正常。包含位置、权限、可用空间。确定无误
3. 查看错误日志
cat /u01/app/oracle/diag/rdbms/orcl/orcl1/trace/orcl1_ora_18338.trc
ORA-00313: 无法打开日志组 4 (用于线程 2) 的成员
DDE: Problem Key ‘ORA 313‘ was flood controlled (0x1) (no incident)
ORA-00313: 无法打开日志组 4 (用于线程 2) 的成员
ORA-00313: 无法打开日志组 4 (用于线程 2) 的成员
Initial buffer sizes: read 1024K, overflow 832K, change 805K
DDE: Problem Key ‘ORA 313‘ was flood controlled (0x1) (no incident)
ORA-00313: 无法打开日志组 4 (用于线程 2) 的成员
ORA-00313: 无法打开日志组 4 (用于线程 2) 的成员
能够看到内存有一定溢出
分析:
经过排查能够确定是日志本身出现了问题,比較官方的解释例如以下
ORA-01624: log string needed
for crash recovery of instance string (thread string).
Cause: A log cannot be dropped or cleared until the thread‘s checkpoint has advanced out of the log..
Action: If the database is not open, then open it. Crash recovery will advance the checkpoint. If the database is open force a global
checkpoint. If the log is corrupted so that the database cannot be opened, it may be necessary to do incomplete recovery until cancel at this log.
大概意思是检查点进程在一直在处理该文件,不能被删除或清除其内容,类似于卡死。能够通过recover来恢复。通过错误日志,我们猜測该问题非常有可能是由于内存溢出造成的。
查看内存:
[[email protected] ~]# free -m
total used free shared buffers cached
Mem: 1878 1736 142 0 6 683
-/+ buffers/cache: 1045 832
Swap: 3999 354 3645
空暇内存不足,而且swap分区发生了交换。确实内存不足。
解决方式:
数据库有rman备份,启动到mount状态进行recover.
SQL>shutdown immediate
SQL>startup mount;
SQL>recover
ORA-00283: 恢复会话因错误而取消
ORA-00264: 不要求恢复
SQL>alter database open;
数据库已更改。
SQL>alter system archive log current;
系统已更改。
回想:
recover的时候报错了。但库启动后能够归档,而且是无损恢复,数据没有不论什么的丢失。那么这个过程发生了什么?
recover会读取日志文件、undo等文件,进行数据库事务的回滚前滚等操作,而在open数据库的时候还会对数据库文件的一致进行处理。
查看alert能够看到下面过程
Thread 2 advanced to log sequence 33 (before internal thread enable)
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl1/trace/orcl1_ora_18338.trc:
ORA-00313: 无法打开日志组 4 (用于线程 2) 的成员
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl1/trace/orcl1_ora_18338.trc:
ORA-00313: 无法打开日志组 4 (用于线程 2) 的成员
Archived Log entry 56 added for thread 2 sequence 32 ID 0xb9a2cd8c dest 1:
Thread 2 advanced to log sequence 34 (after internal thread enable)
Wed Jul 22 18:28:47 2015
ARC2 started with pid=35, OS id=18513
Wed Jul 22 18:28:47 2015
Thread 1 opened at log sequence 39
Current log# 1 seq# 39 mem# 0: +DATA_DG/orcl/onlinelog/group_1.257.885126161
Current log# 1 seq# 39 mem# 1: /orabak/clog/orcl01.log
Successful open of redo thread 1
MTTR advisory is disabled because FAST_START_MTTR_TARGET is not set
Wed Jul 22 18:28:47 2015
SMON: enabling cache recovery
Instance recovery: looking for dead threads
Instance recovery: lock domain invalid but no dead threads
ARC1: Archival started
能够看到Oracle进行了缓存的恢复并对死进程进行了处理。