topic Re: How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX in Administration and Deployment

How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX

Akshay1005 — Wed, 18 Jan 2023 10:56:14 GMT

Hello Experts,

Hope you are doing good

Am actually new to SAS 9.4 and it is run on a AIX platform.

Wanted to know the best AIX command to find SAS 9.4 Ghost or Zombie or Defunct session on the AIX machine so that we can kill them.

Can anyone please help?

Thanking you in advance

Re: How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX

Morse_Bill — Wed, 18 Jan 2023 15:04:18 GMT

Hello,

it might help if you explain what type of 'session' -- SAS EG sessions, batch jobs, interactive SAS sessions?

Re: How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX

Kurt_Bremser — Wed, 18 Jan 2023 17:18:10 GMT

Start with

ps -ef|pg

and look at the output.

Re: How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX

Akshay1005 — Thu, 19 Jan 2023 08:05:07 GMT

yes we have batch jobs, users EG sessions and also interactive sas sessions. I was thinking of something like this:
ps aux | awk {'print $2'}|grep "defunct" |grep sas
ps aux | awk {'print $2'}|grep Z |grep sas

Re: How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX

Akshay1005 — Thu, 19 Jan 2023 08:06:11 GMT

Thanks Kurt. Idea here is find all SAS zombies/ghost/defunct processes for kill. I was thinking of something like that:
ps aux | awk {'print $2'}|grep "defunct" |grep sas
ps aux | awk {'print $2'}|grep Z |grep sas

I don't know if that will be OK

Re: How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX

Kurt_Bremser — Thu, 19 Jan 2023 08:26:48 GMT

You need to first find a real appearance of what you define as "ghost process", and then create a suitable identifying pattern for the grep. I don't think that the intermediate awk is necessary.

It has been a very long time now that I found real "defunct" remnants of SAS processes in the AIX process list; defunct means a process has terminated and the parent process doesn't acknowledge this.

Re: How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX

Sajid01 — Fri, 20 Jan 2023 03:06:56 GMT

Your question is "Wanted to know the best AIX command to find SAS 9.4 Ghost or Zombie or Defunct session on the AIX machine so that we can kill them".
The system administrator cannot kill the Zombie process. They are removed by the parent process or the OS.
You can however kill the parent process. If the number of Zombies is high or parent cannot be killed then reboot is the option.
The Unix/AIX Admin of your installation is the appropriate resource to reach out to.

Re: How to identify SAS 9.4 Ghost/Zombie/Defunct session on AIX

Kurt_Bremser — Fri, 20 Jan 2023 08:15:43 GMT

And yes, a "defunct" process cannot be killed, because that already happened. "defunct" means that only the entry in the process list remains because the termination has not been picked up (through a wait() call) by the parent process. Sometimes, sending a kill -1 to the parent process works, but such a situation usually points to a code issue in the parent (e.g. the SAS object spawner).

By killing/terminating the parent, the system init process takes over all its children and will remove them after receiving the -1 signal (kill -1 1). If that also fails, a system reboot is in order. Although I haven't seen that happening for a long time now (>10 years, not with AIX 6/7 and SAS 9.2 and above)