Error in listener log

[satish]

Hi erman,

Error in listener log.What may be the reasons for below error.some people say it is due to high load in server.Need your expertise.

msg>
<msg time='2021-08-24T09:49:20.054+05:30' org_id='oracle' comp_id='tnslsnr'
type='UNKNOWN' level='16' host_id='ttd-db01-new'
host_addr='fe80::e68e:d35b:2766:6ad5%ens192'>
<txt>TNS-12518: TNS:listener could not hand off client connection
TNS-12536: TNS:operation would block
  TNS-12560: TNS:protocol adapter error
   TNS-00506: Operation would block
    Linux Error: 11: Resource temporarily unavailable
</txt>


We are unable to open this https://access.redhat.com/solutions/417883


Rhel 7.3
DB 12.1.0.2.0

Thank you

[ErmanArslansOracleBlog]

Check the resources ... OS resources.. Ulimit.. Max processes , max open file limits..
It is obvious that there is a resource problem in the OS.

[satish]

I am sry to ask but we are completely out of ideas and in pressure.Can u pls provide some important files to look at

[satish]

Hi erman,

We checked below files.

oracle@test-db01-new ~]$ ls -lrt /etc/security/limits.conf
-rw-r--r-- 1 root root 2603 Aug 17 11:46 /etc/security/limits.conf

[oracle@test-db01-new ~]$ cat /etc/security/limits.conf

oracle soft nproc 65536
oracle hard nproc 65536
oracle soft nofile 65536
oracle hard nofile 65536
oracle soft stack 10240
oracle soft memlock unlimited
oracle hard memlock unlimited
# End of file
[oracle@test-db01-new ~]$


[oracle@test-db01-new ~]$ ulimit
unlimited
[oracle@test-db01-new ~]$

But after restarting listener, error didn’t appear.Some argue this due to high cpu consumption on server.Anything else to check.Pls advice.

We have 48vcpu and processes as 15000 and sessions as 26000

Thank you

[ErmanArslansOracleBlog]

No. "It is directly related with the OS limits.."

It is not related with Cpu utilization or consumption..

[satish]

Dear erman,

From note I’d 1920559.1,it says kernel parameters are wrong as you said before.

But based on what what configuration,oracle gave these recommended values for shmax and shmall.Can we use it in our case also?pls suggest..our existing kernel parameters almost similar as in noteid

Thank you

[ErmanArslansOracleBlog]

That note gives the solution from the surface.
Those kernel parameters may be involved but may not be involved as well..

Limits.conf is important and some kernel parameters should also be aligned with those limits setting.
Limits should be aligned with the workload. Especially max nproc and max nofile.

Those limits and the values of the kernel parameters should be set according to your environment, your resources and your workload.

so please read about limits.conf and /etc/sysctl.conf and decide for a logical increase in the values of the related paremeters.

check the following blog post -> https://ermanarslan.blogspot.com/2014/11/ebslinux-fork-retry-resource.html
This blog post will give you the idea for approaching this issue..

[satish]

Thank you

We have recently moved to New server which is having double the CPU core when compared to old server..Os team verified all the required files like sysctl.conf,limits.conf.It has same values as in old server.In old server,we didn't face this listener issue.


I verified thr processess and sessions parameters are increased in New server when compared to old server,Ram is also increased in New server.
New server is vm and old server is physical.When we increase the parameters,should we increase any kernel parameter?

Thank you

[ErmanArslansOracleBlog]

There is no casual line between those 2. But yes in your case you need to increase those limits.