DWS_2000000026 Data Written by a CN Instance in a DWS Cluster to Disks Exceeds the Threshold

Alarm Description

This alarm is generated when the DMS alarm module detects that the amount of data written by a CN instance in a DWS cluster to disks exceeds the threshold in a specified period and the suppression conditions are not met. This alarm is cleared when the DMS alarm module detects that the amount of data written by a CN instance in a DWS cluster to disks is lower than the threshold.

Alarm Attributes

Alarm ID	Alarm Category	Alarm Severity	Alarm Type	Service Type	Auto Cleared
DWS_2000000026	Management plane	> 500 (critical)	Service alarm	DWS	Yes

Alarm Parameters

Type	Parameter	Description
Location information	Cluster name	Cluster for which the alarm is generated.
	Tenant name	Name of the tenant to which the cluster belongs.
	Alarm severity	Severity of the alarm.
Other information	Resource ID	ID of the cluster for which the alarm is generated.
	Resource name	Cluster for which the alarm is generated.
	Instance name	Name of the CN for which the alarm is generated.
	First_alarm_time	First occurrence event of an alarm, including the alarm threshold and current value.

Impact on the System

If data is written by a CN to disks during SQL statement execution, the memory is insufficient, and the cluster may become read-only. As a result, the statement execution is slow, and the lock is held for a long time, affecting service execution.

Possible Causes

The memory space used by the cluster is insufficient.
The SQL statement is not optimized, and the execution efficiency is low.

Procedure

Obtain the query ID of the SQL statement that writes more data to disks than the threshold. For details about how to obtain the query ID, see Service Analysis.
Return to the DWS console.
Choose Dedicated Clusters > Clusters, locate the row that contains the cluster for which the alarm is generated, and click Monitoring Panel in the Operation column.
Choose Monitoring > Real-Time Queries and click the Real-Time Queries tab to view the data written to disks.
After confirming with the service side, select the query ID of the query to be stopped and click Stop Query.