Errors in Alert Log File of Instances

These are the following Errors/Warning messages which we will get in release Instances alert log files.  Find the following work arounds/solutions, what I have successfully applied.

 Problem 1:

 Memory Notification: Library Cache Object loaded into SGA
Heap size 6237K exceeds notification threshold (2048K)

These are warning messages only which should not cause any problems. These warning messages appear due to new event messaging mechanism and memory manager in 10g Release 2. In 10g R2 we have a new undocumented parameter that sets the KGL heap size warning threshold. Warnings are written if heap size exceeds this threshold. 

Set    _kgl_large_heap_warning_threshold to a reasonable high value to prevent these warning messages: Default Threshold in is 2 MB only. But Default Threshold value in is 50 MB which is reasonable and recommended value.  


SQL> alter system set “_kgl_large_heap_warning_threshold”= 52428800 scope=spfile;

SQL> shutdown immediate; 

SQL> startup;   

Problem 2: 

Trace file created when RMAN issues the controlfile autobackup. 

Following messages will be appeared in alert log file 

Errors in file /oracle/product/
Control autobackup written to DISK device
handle ‘/backup/flash_recovery_area/PROD/autobackup/2008_01_04/o1_mf_s_648508685_3wv4m226_.bkp’ 

 These messages do not have any impact. Only problem is when ever RMAN issues the control file autobackup command, it will create one trace file with the above errors.  

Work around  

(1)   This is a bug fixed in or       


(2) Write an OS cron job to delete the trace files 


330239.1. Memory Notification: Library Cache object loaded into SGA 

 Note: If you are having above problems with your instances, Please login as SR to Oracle Support and then implement the solution under their guidance.       

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About the Author Atul Kumar

Leave a Comment:

mahmedocp says March 30, 2008

Hi All,

Im getting this Error(warning) in Alert Log file Database version and Oracle Apps

WARNING:Oracle instance running on a system with low open file descriptor
limit. Tune your system to increase this limit to avoid
severe performance degradation.

Can u please suggest me what to do…?


amit says March 30, 2008

Hi Ahmed,

Increase the number of file descriptors or reduce the number of db_files
parameter in init.ora and restart the database.

Let me know if you have any issue.


SubbaRao says March 30, 2008


As Amit said, this is mainly because of too high of a setting for the db_files database parameter or too low of a setting for the OS open file descriptor parameter.

To solve the problem, decrease the db_files parameter value or increase the open file descriptors limit value specific to your os kernel….

the following metalink note might be helpful to increase the open file descriptors limit

How to Display and Change UNIX Process Resource Limits Note:188149.1


mahmedocp says March 31, 2008


Thanks for ur quick responses its very help full for me the oracle NOTE:

Thanks a lot.

SubbaRao says March 31, 2008

Welcome my friend,

I really appreciate your words,


ramakrishna says November 12, 2008

hi i am ramakrishna to find how many ptches are installed in my database?
2.what is the use of script?
3.Why small tables keep in keep pool & big tables keep in recycle pool
4.One user is not possible to access the database means it will take more time to access what can you do as an DBA
5.What is use of execution plan

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