打开游标数量

chunchun2012

昨天数据库中出现了几条警告，提示Metrics "Current Open Cursors Count" is at 1332,详情请见附件。
请问一下数据库当前打开的游标数一般在哪个范围内是正常的，或者说，如何判断当前打开的游标数没有超出正常范围？

chunchun2012

前几天有点事没时间上网，刚刚才看到回复，学习了，谢谢maclean!

Maclean Liu(刘相兵

ODM FINDING:

Applies to:
Enterprise Manager for RDBMS - Version: 10.1.0.2 to 10.2.0.4 - Release: 10.1 to 10.2
Information in this document applies to any platform.


Symptoms

The following warning is raised by the  Enterprise Manager :
Message: Metrics "Current Open Cursors" is at 1651

Checking the parameter 'open_cursors' shows a value of 1024
Cause

The current open cursors warning message is raised based on the value of v$sysstat which is for system wide but the parameter "open_cursors" specifies the maximum number of open cursors (handles to private SQL areas) a session can have at once.

The cursors opened depend on application and it is perfectly ok to open more cursors (depending on application and current users on the DB). If you want to avoid this warning, set the value of this metric to some high value.

The default warning metric threshold is set to 1200, this value might not be suitable for most production environments.

Solution

The following steps describe how to set metric thresholds through the Enterprise Manager:

From the Database Home page, click Manage Metrics under the Related Links heading.

1-The Manage Metrics page is displayed. It displays the existing thresholds for metrics and any response actions that have been specified.

2-Click Edit Thresholds.

3-Modify the current value of "Current Open Cursors Count" to a higher value.





除非 open cursors count 过多导致 01000, 00000, "maximum open cursors exceeded" 或者其他明显的 性能问题 ， 否则一般可以 忽略 该 Metric 度量警告