今天发现Oracle数据库很慢,看到大量进程在等待log file switch (checkpoint incomplete),日志文件的使用情况如下:SYS@TEST15
今天发现Oracle数据库很慢,看到大量进程在等待log file switch (checkpoint incomplete),日志文件的使用情况如下:
SYS@TEST15>select group#,sequence#,bytes/1024/1024 "BYTES(M)",members,archived,status from v$log;
GROUP# SEQUENCE# BYTES(M) MEMBERS ARC STATUS
---------- ---------- ---------- ---------- --- ----------------
1 205 100 2 YES ACTIVE
2 206 100 2 NO CURRENT
3 204 100 2 YES ACTIVE
SYS@TEST15>select group#,status,type,member from v$logfile where type='ONLINE' order by type,group#;
GROUP# STATUS TYPE MEMBER
---------- ------- ------- ------------------------------------------------------------
1 ONLINE /data/oradata/orcl/data/redo01a.log
1 ONLINE /home/oracle/data/orcl/redo01b.log
2 ONLINE /data/oradata/orcl/data/redo02a.log
2 ONLINE /home/oracle/data/orcl/redo02b.log
3 ONLINE /data/oradata/orcl/data/redo03a.log
3 ONLINE /home/oracle/data/orcl/redo03b.log
从上面可以看出,所有的日志文件都是ACTIVE或CURRENT状态,这说明日志文件太小,需增加其大小。
但在线重做日志不可以直接RESIZE,需要通过如下方式:
1)添加新的日志文件组,定义它的大小
SYS@TEST15>alter database add logfile group 4 ('/data/oradata/orcl/data/redo04a.log','/home/oracle/data/orcl/redo04b.log') size 500M reuse;
Database altered.
2)持续切换日志,一直到Group 1的status=inactive,且archived=yes(如果为归档的话),如下所示:
SYS@TEST15>alter system switch logfile;
SYS@TEST15>alter system checkpoint;
SYS@TEST15>select group#,sequence#,bytes/1024/1024 "BYTES(M)",members,archived,status from v$log where group#=1;
GROUP# SEQUENCE# BYTES(M) MEMBERS ARC STATUS
---------- ---------- ---------- ---------- --- ----------------
1 214 100 2 YES INACTIVE
3)删除Group 1
SYS@TEST15>alter database drop logfile group 1;
Database altered.
这样,我们就完成了用更大的Group 4取代原有的Group 1,至于Group 2, Group 3以此类推。
最后,,还要记得到操作系统上把日志文件删除。
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