ALM-50211 FE Queue Length of BE Periodic Report Tasks Exceeds the Threshold

Alarm Description

The system checks the queue length of each BE periodic report task on FE every 30 seconds. This alarm is generated when the queue length exceeds the threshold (10 by default). This value indicates the number of report tasks waiting on the master FE node. A large value indicates a poor FE processing capability.

This alarm is cleared when the system detects that the queue length of BE periodic report tasks on FE is less than the threshold.

Alarm Attributes

Alarm ID	Alarm Severity	Alarm Type	Service Type	Auto Cleared
50211	Minor	Quality of service	Doris	Yes

Alarm Parameters

Type	Parameter	Description
Location Information	Source	Specifies the cluster or system for which the alarm is generated.
	ServiceName	Specifies the service for which the alarm is generated.
	RoleName	Specifies the role for which the alarm is generated.
	HostName	Specifies the host for which the alarm is generated.
Additional Information	Detail	Specifies the alarm triggering condition.

Impact on the System

The processing capability of FE is insufficient, affecting the service query speed.

Possible Causes

The processing capability of the master FE node is insufficient due to a large number of concurrent service requests in the Doris cluster or insufficient memory for FE processes.

Handling Procedure

Check the GC duration.

On FusionInsight Manager, choose O&M > Alarm > Alarms. In the alarm list, view the role name and obtain the IP address of the instance in Location of the alarm whose ID is 50211.
Choose Cluster > Services > Doris > Instances, click the FE instance for which the alarm is generated, and click the Chart tab of the instance.
Select JVM from Chart Category on the left, and check whether Accumulated GC duration of the old generation of the FE process is greater than 3 seconds.
- If yes, go to 3.
- If no, go to 5.
Choose Cluster > Services > Doris > Configurations > All Configurations > FE(Role) > JVM, and increase the value of -Xmx in FE_GC_OPTS. The default value is 8GB.
- If this alarm is generated occasionally, increase the value by 0.5 times. If this alarm is generated frequently, double the parameter value.
- In the case of large service volume and high service concurrency, you are advised to add instances.
Check whether the alarm is cleared.
- If yes, no further action is required.
- If no, go to 5.

Check whether the alarm threshold or alarm trigger count is properly configured.

Log in to FusionInsight Manager, choose O&M > Alarm > Thresholds, click the name of the desired cluster, and choose Doris > Queue > Queue Length of BE Periodic Report Tasks on the FE (FE).
Click the edit button next to Trigger Count, change the number based on site requirements, and click OK.
Click Modify in the Operation column, change the alarm threshold based on site requirements, and click OK.
Wait 2 minutes and check whether the alarm is automatically cleared.
- If yes, no further action is required.
- If no, go to 9.

Collect fault information.

On FusionInsight Manager, choose O&M. In the navigation pane on the left, choose Log > Download.
Expand the Service drop-down list, and select Doris for the target cluster.
Click the edit icon in the upper right corner, and set Start Date and End Date for log collection to 10 minutes ahead of and after the alarm generation time, respectively. Then, click Download.
Contact O&M engineers and provide the collected logs.