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Title
QUESTION: When does Stealth Collect get restarted? -
Description
QUESTIONS:
1. What triggers the Stealth Collection processes to restart and how often should we see the processes being restarted?
2. But while investigating the issue, I saw a note that said the Stealth Collect processes should stop running if Oracle isn't running. I checked 3 database servers where the databases are shutdown nightly, and I observed the Stealth Collect processes were started on Aug 7 on server 1, Aug 14 on server 2, and Aug 17 (today) on server 3.
3. Or is what I am observing normal behaviour and the processes may be alive for a week or more?
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Resolution
ANSWER:
1. What triggers the Stealth Collection processes to restart and how often should we see the processes being restarted?
Any time, the PA agent responsible to receive the data collection (PA Middleware agent) detects that data communication channel is blocked, it attempts to resolve the issue by restarting PA data collecting component (PA Collector agent). Thus it is normal to see that sometimes PAO Middleware agent restarts the PAO agent Collector process. It may be as infrequent as once in 2 weeks (this indicates a good healthy status) or it may be as frequent as 5 to 10 times per day. Restart of Collector process does not indicate a problem by itself but if the same restarts happen very frequently, then data collection is impacted and you may see “data gaps” in PA Client in Real Time. This is a problem and we will need to investigate this further.
2. But while investigating the issue, I saw a note that said the Stealth Collect processes should stop running if Oracle isn't running. I checked 3 database servers where the databases are shutdown nightly, and I observed the Stealth Collect processes were started on Aug 7 on server 1, Aug 14 on server 2, and Aug 17 (today) on server 3.
This is incorrect inference. When monitored Oracle DB instance is stopped, the corresponding PAO agent Collector process will run in futile cycles but will not “stop”. The Collector process is unable to attach to DB memory segments since the DB is not available; It can be seen running in the process listing and is needlessly consuming resources on Monitored Host.
Since you are stopping the Oracle DB instance as a planned step, the correct approach would be to incorporate the commands to stop PA agent services into the Oracle DB Stop/Start scripts. PA agent should be stopped when the monitored Oracle DB is stopped and the same restarted automatically with DB restart, if such scripts are scripted correctly.
3. Or is what I am observing normal behaviour and the processes may be alive for a week or more?
Yes. PA Collector process will run as long as the parent PA agent service (quest_launcher) is running.
In this case, it appears that whenever the monitored Oracle DB is stopped, PA agent Collector process is not sending any data since there is nothing to send and Middleware agent, sensing that there is no data collection happening, is most likely doing repeated restarts of Collector process.If you are noticing that PA agent Collector process is restarting frequently even when monitored Oracle DB is up and running, there may be another reason behind frequent restarts of Collector, which we have to investigate further.
Please review and let us know any question or have you seen PA agent Collector process is restarting frequently even when monitored Oracle DB is up and running?