RMAN备份遭遇ORA－00494

ALLSTARS_ORACLE

服务器宕机，数据库版本10.2.5：

Errors in file /oracle/oracle/admin/wind/bdump/wind_arc1_15952.trc:
ORA-00494: enqueue held for too long (more than 900 seconds) by 'inst 1, osid 670'
Wed Mar 25 00:56:24 CST 2015
System State dumped to trace file /oracle/oracle/admin/wind/bdump/wind_arc1_15952.trc
Wed Mar 25 00:56:43 CST 2015
Killing enqueue blocker (pid=670) on resource CF-00000000-00000000
by terminating the process
Wed Mar 25 00:56:43 CST 2015
Attempt to get Control File Enqueue by ARC1 pid=15952 (mode=S, type=0, timeout=300) is being blocked by inst=1, pid=670
Please check inst 1's alert log for more information on the blocker including a possible ORA-00494 and related incident logs
Wed Mar 25 01:00:05 CST 2015
Errors in file /oracle/oracle/admin/wind/udump/wind_ora_4138.trc:
ORA-00494: enqueue held for too long (more than 900 seconds) by 'inst 1, osid 670'
Wed Mar 25 01:00:35 CST 2015
System State dumped to trace file /oracle/oracle/admin/wind/udump/wind_ora_4138.trc
Wed Mar 25 01:00:53 CST 2015
Killing enqueue blocker (pid=670) on resource CF-00000000-00000000
by killing session 1049.8563
Wed Mar 25 01:00:53 CST 2015
Attempt to get Control File Enqueue by USER pid=4138 (mode=S, type=0, timeout=900) is being blocked by inst=1, pid=670
Please check inst 1's alert log for more information on the blocker including a possible ORA-00494 and related incident logs
Wed Mar 25 01:13:37 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:30:22 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:38:42 CST 2015
WARNING: aiowait timed out 1 times
Wed Mar 25 01:40:22 CST 2015
WARNING: aiowait timed out 2 times
Wed Mar 25 01:44:01 CST 2015
Errors in file /oracle/oracle/admin/wind/bdump/wind_arc0_15950.trc:
ORA-00494: enqueue held for too long (more than 900 seconds) by 'inst 1, osid 15900'
Wed Mar 25 01:44:02 CST 2015
System State dumped to trace file /oracle/oracle/admin/wind/bdump/wind_arc0_15950.trc
Wed Mar 25 01:44:21 CST 2015
Killing enqueue blocker (pid=15900) on resource CF-00000000-00000000
by killing session 1081.1
Killing enqueue blocker (pid=15900) on resource CF-00000000-00000000
by terminating the process
ARC0: terminating instance due to error 2103
Termination issued to instance processes. Waiting for the processes to exit
Wed Mar 25 01:44:31 CST 2015
Instance termination failed to kill one or more processes
Instance terminated by ARC0, pid = 15950
Wed Mar 25 07:58:29 CST 2015
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Picked latch-free SCN scheme 3
IMODE=BR
ILAT =121
LICENSE_MAX_USERS = 0
SYS auditing is disabled
ksdpec: called for event 13740 prior to event group initialization

搜到的一些解决方案，生产库不敢尝试贸然修改，哪位大神遇到过，帮忙给个指点吧？

ORA-00494 enqueue held for too long tips   

Oracle Tips by Burleson Consulting

August 8, 2012







Question:I am getting an ORA-00494 error and the trace file.This error causes my database to crash:.

ORA-00494: enqueue held for too long

/u01/app/oracle/admin/mysid/bdump/ora_lgwr_143.trc

Killing enqueue blocker (pid=152) on resource

CF-00000000-00000000 by killing session 83.0


What is the cure for this ORA-00494 error?

Answer:The oerr utility shows this on the ORA-00494

ORA-00494: enqueue string held for too long (more than string seconds) by 'inst string, osid string'

Cause:The specified process did not release the enqueue within the maximum allowed time.

Action:Reissue any commands that failed and contact Oracle Support Services with the incident information.

The ORA-00494 error occurs during periods of super-high stress, activity to the point there the server becomes unresponsive due to overloaded disk I/O, CPU or RAM.
•See MOSC Note ID 779552.1 "ORA-00494 During High Load After 10.2.0.4 Upgrade" says that Oracle kills blocking processes during periods of high DML load and issues the ORA-00494 error.In your case, it is the log writer process.

•Also see Database Crashes With ORA-00494 [MOSC Note ID 753290.1

Solutions for ORA-00494:
•Resize online redo logs

•Spread-out the DML over longer periods

•Adjust several hidden parameters:

Two Oracle database hidden parameters can be reconfigured to prevent further incident happens by the same cause – Oracle Kill Blocker Interface mechanism:

1) _kill_controlfile_enqueue_blocker = { TRUE | FALSE }
•TRUE. Default value. Enables this mechanism and kills blocker process in CF enqueue.
•FALSE. Disables this mechanism and no blocker process in CF enqueue will be killed.

2) _kill_enqueue_blocker = { 0 | 1 | 2 | 3 }
•0. Disables this mechanism and no foreground or background blocker process in enqueue will be killed.
•1. Enables this mechanism and only kills foreground blocker process in enqueue while background process is not affected.
•2. Enables this mechanism and only kills background blocker process in enqueue.
•3. Default value. Enables this mechanism and kills blocker processes in enqueue.

3) _controlfile_enqueue_timeout = { INTEGER }
•900. Default value.
•1800. Optimum value to prevent enqueue timeout

不胜感激。。。。