Help Center/ MapReduce Service/ User Guide (Ankara Region)/ Alarm Reference/ ALM-45442 Too Many Concurrent SQL Statements
Updated on 2024-11-29 GMT+08:00
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ALM-45442 Too Many Concurrent SQL Statements

This section applies only to MRS 3.3.0 or later.

Alarm Description

The alarm module checks the number of concurrent ClickHouse requests every 30 seconds. This alarm is generated when the number of concurrent ClickHouse requests exceeds the concurrency threshold configured on the UI.

This alarm is cleared when the system detects that the actual number of concurrent requests is less than concurrency threshold.

Alarm Attributes

Alarm ID

Alarm Severity

Alarm Type

Service Type

Auto Cleared

45442

Major

Quality of service

ClickHouse

Yes

Alarm Parameters

Type

Parameter

Description

Location Information

Source

Specifies the cluster or system for which the alarm was generated.

ServiceName

Specifies the service for which the alarm was generated.

RoleName

Specifies the role for which the alarm was generated.

HostName

Specifies the host for which the alarm was generated.

Impact on the System

If there are too many concurrent SQL statements, a large number of system resources are consumed. As a result, system response becomes slow.

Possible Causes

The ClickHouse service is overloaded.

Handling Procedure

  1. Log in to FusionInsight Manager, choose O&M > Alarm > Alarms, and view the role name and the IP address for the hostname in Location.
  2. Choose Cluster > ClickHouse > Instance, select an instance based on the alarm information. Choose Chart > Concurrency to check whether the actual number of concurrent SQL statements is greater than SQL concurrency threshold.

    • If yes, go to 3.
    • If no, go to 5.

  3. Confirm with the user whether a large number of tasks were being executed during the alarming period.

    • If yes, go to 4.
    • If no, go to 5.

  4. On FusionInsight Manager, choose O&M and click Alarm > Thresholds in the navigation pane on the left. On the displayed page, click ClickHouse > Concurrency and adjust the threshold, or wait until the task is complete. Check whether the alarm is cleared.

    • If yes, no further action is required.
    • If no, go to 5.

Collect fault information.

  1. On FusionInsight Manager, choose O&M. In the navigation pane on the left, choose Log > Download.
  2. Expand the Service drop-down list, and select ClickHouse for the target cluster.
  3. Expand the Hosts drop-down list. In the Select Host dialog box that is displayed, select the abnormal host, and click OK.
  4. Click the edit icon in the upper right corner, and set Start Date and End Date for log collection to 1 hour ahead of and after the alarm generation time, respectively. Then, click Download.
  5. Contact O&M engineers and provide the collected logs.

Alarm Clearance

This alarm is automatically cleared after the fault is rectified.

Related Information

None.

Parent topic: Alarm Reference