Description

The system collects GC time of the Presto Worker process every 30 seconds. This alarm is generated when the GC time exceeds the threshold (exceeds 5 seconds for three consecutive times). You can change the threshold by choosing System > Configure Alarm Threshold > Service > Presto > Worker > Presto Garbage Collection Time > Garbage Collection Time of the Worker Process on MRS Manager. This alarm is cleared when the Worker process GC time is shorter than or equal to the threshold.

Attribute

Alarm ID	Alarm Severity	Auto Clear
44006	Major	Yes

Parameter

Parameter	Description
ServiceName	Service for which the alarm is generated.
RoleName	Role for which the alarm is generated.
HostName	Host for which the alarm is generated.

Impact on the System

If the GC time of the Worker process is too long, the Worker process running performance will be affected and the Worker process will even be unavailable.

Possible Causes

The heap memory of the Worker process is overused or inappropriately allocated, causing frequent occurrence of the GC process.

Procedure

Check the GC time.
1. Go to the cluster details page and choose Alarms.
  
  For MRS 1.8.10 or earlier, log in to MRS Manager and choose Alarms.
2. Select the alarm whose Alarm ID is 44006. Then check the role name in Location and confirm the IP adress of the instance.
3. Choose Components > Presto > Instances > Worker (business IP address of the instance for which the alarm is generated) > Customize > Presto Garbage Collection Time. Click OK to view the GC time.
4. Check whether the GC time of the Worker process is longer than 5 seconds.
  - If yes, go to 1.e.
  - If no, go to 2.
5. Choose Components > Presto > Service Configuration, and switch Basic to All, and choose Presto > Worker Increase the value of -Xmx (maximum heap memory) in the JAVA_OPTS parameter based on the site requirements.
6. Check whether the alarm is cleared.
  - If yes, no further action is required.
  - If no, go to 2.
Collect fault information.
1. On MRS Manager, choose System > Export Log.
2. Call the OTC Customer Hotline for support.
  Germany: 0800 330 44 44
  
  International: +800 44556600

Reference

None