Help Center/Data Warehouse Service/Management Guide/DWS Cluster O&M/Viewing and Subscribing to DWS Cluster Alarms/Alarm Handling/1078919169 DWS Data Instance Connections Exceed the Threshold
Updated on 2025-09-11 GMT+08:00
View PDF

1078919169 DWS Data Instance Connections Exceed the Threshold

Alarm Description

This alarm is generated when the number of client connections to a CN exceeds the threshold (specified by parameter max_connections*connection_alarm_rate) configured in the postgresql.conf file.

Alarm Attributes

Alarm ID

Alarm Category

Alarm Severity

Alarm Type

Service Type

Auto Cleared

1078919169

Tenant plane

Important

Service quality alarm

DWS instance

Yes

Alarm Parameters

The number of parameters varies according to alarms.

Type

Parameter

Description

Location Information

instance_id

ID of the instance for which the alarm is generated

instance_name

Name of the instance that reports the alarm

domain_name

Domain name for which the alarm is generated

domain_id

Domain ID for which the alarm is generated

datastore_type

Type of the data storage for which the alarm is generated

instance_role

Role of the instance for which the alarm is generated

component_instance_name

Name of the component instance that reports the alarm, for example, cn_5001.

Additional Information

CloudService

Name of the cloud service for which the alarm is generated

resourceId

Resource ID for which the alarm is generated

resourceIdName

Resource for which the alarm is generated

domain_name

Domain name for which the alarm is generated

domain_id

Domain ID for which the alarm is generated

Impact on the System

New clients cannot connect to a CN.

System Actions

None

Possible Causes

The number of clients connected to a CN exceeds the threshold (specified by parameter max_connections*connection_alarm_rate) configured in the postgresql.conf file.

Procedure

  1. Log in to the DWS console.
  2. On the Alarm page, view the alarms generated in the last seven days.
  3. Choose Cluster > Cluster List and locate the cluster based on the cluster information in the alarm details.
  4. Click the cluster name to go to the cluster details page. Choose Parameter Modifications, search for max_connections in the search box on the right of the parameter list, and change its value.

    Determine whether to increase the value of max_connections for CNs and DNs based on the following rules. The default value is 800 for CNs and 5,000 for DNs.
    • Increasing the value of max_connections for CNs will increase the number of concurrent queries connected to DNs. Therefore, you need to increase the values of max_connections and comm_max_stream for DNs.
    • Increase the value of max_connections for CNs/DNs by twice. For clusters with a small value, you can increase it by four times.
    • To avoid failures in the preparation step, the value of max_prepared_transactions should at least be equal to that of max_connections. This ensures that each session has a prepared transaction in waiting state.
    Figure 1 Modifying parameters

  5. Confirm the information and click Save.

Alarm Clearance

This alarm is automatically cleared after the fault is rectified.

Related Information

N/A

Parent Topic: Alarm Handling