Private strand flush not complete错误

(2013-10-22 11:04:58)

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分类： FAQ

最近的一个报表系统数据库，总是出现checkpoint not complete错误或者Private strand flush not complete错误，具体如下：

Mon Oct 7 09:49:20 2013

Thread 1 cannot allocate new log, sequence 132198

Checkpoint not complete

Current log# 1 seq# 132197 mem# 0: /data/oradata/testrpt/redo01.log

Mon Oct 7 09:49:59 2013

Thread 1 advanced to log sequence 132198

Current log# 2 seq# 132198 mem# 0: /data/oradata/testrpt/redo02.log

Mon Oct 7 12:10:41 2013

Thread 1 advanced to log sequence 132199

Current log# 3 seq# 132199 mem# 0: /data/oradata/testrpt/redo03.log

Mon Oct 7 19:04:43 2013

Thread 1 cannot allocate new log, sequence 132200

Private strand flush not complete

Current log# 3 seq# 132199 mem# 0: /data/oradata/testrpt/redo03.log

Thread 1 advanced to log sequence 132200

Current log# 1 seq# 132200 mem# 0: /data/oradata/testrpt/redo01.log

根据check point not complete错误，决定采取增加日志文件来缓解出现频率，具体步骤如下：

sys@testrpt> select * from v$logfile;

sys@testrpt> set wrap off

sys@testrpt> /

rows will be truncated

GROUP# STATUS TYPE MEMBER

---------- ------- ------- -----------------------------------------------------

3 ONLINE /data/oradata/testrpt/redo03.log

2 ONLINE /data/oradata/testrpt/redo02.log

1 ONLINE /data/oradata/testrpt/redo01.log

sys@testrpt> select group#,bytes/1024/1024 m from v$log;

GROUP# M

---------- ----------

1 200

2 200

3 200

sys@testrpt> alter database add logfile group 4

2 '/data/oradata/testrpt/redo04.log' size 200m;

Database altered.

sys@testrpt> alter database add logfile group 5

2 '/data/oradata/testrpt/redo05.log' size 200m;

Database altered.

sys@testrpt> alter database add logfile group 6

2 '/data/oradata/testrpt/redo06.log' size 200m;

Database altered.

针对 Private strand flush not complete问题 Oracle 提了2个方法：

（1）忽略，在使用之前，必须要等待buffer的信息flush完成。这时候进程是会短暂的hang住。

（2）增加db_writer_process的数据。

sys@testrpt> show parameter db_wri

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

db_writer_processes integer 1

该参数的静态参数，需要重启数据库才能生效：

sys@testrpt> alter system set db_writer_processes=3;

alter system set db_writer_processes=3

ERROR at line 1:

ORA-02095: specified initialization parameter cannot be modified

因此需要采取如下方式来使其生效：

sys@testrpt> alter system set db_writer_processes=3 scope=spfile;

System altered.

sys@testrpt> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

sys@testrpt> startup

ORACLE instance started.

Total System Global Area 2147483648 bytes

Fixed Size 1220432 bytes

Variable Size 285212848 bytes

Database Buffers 1845493760 bytes

Redo Buffers 15556608 bytes

Database mounted.

Database opened.

sys@testrpt> alter system register;

System altered.

sys@testrpt> show parameter db_write

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

db_writer_processes integer 3

sys@testrpt> alter system switch logfile;

System altered.

sys@testrpt>

sys@testrpt> exit

以上操作完毕后，查看bdump文件夹，又出现了名称testrpt_lgwr_26081.trc 具体内容如下：