Help Center/ MapReduce Service/ User Guide (Ankara Region)/ Alarm Reference/ ALM-45445 Failed to Send Data Files to Remote Shards When ClickHouse Writes Data to a Distributed Table

Updated on 2024-11-29 GMT+08:00

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ALM-45445 Failed to Send Data Files to Remote Shards When ClickHouse Writes Data to a Distributed Table

This section is available for MRS 3.3.1 or later version only.

Alarm Description

The ClickHouse instance checks the distributed table every 300 seconds. If the number of consecutive failures exceeds the threshold, an alarm is generated. In this case, the node where the ClickHouse instance writes data to the distributed table cannot send data files to remote shard nodes.

Alarm Attributes

Alarm ID	Alarm Severity	Alarm Type	Service Type	Auto Cleared
45445	Major	Quality of service	ClickHouse	Yes

Alarm Changes

Change Type	Version	Description	Reason for Change
New	3.3.1	New alarm	New alarm

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

The results of operations such as distributed table queries are abnormal.

Possible Causes

The status of some ClickHouse shard nodes is abnormal.

Handling Procedure

Log in to FusionInsight Manager, choose O&M > Alarm > Alarms, and view the role name and the IP address of the hostname in Location.
Log in to the node where the client is installed as the client installation user and run the following commands:

cd {Client installation path}

source bigdata_env
- For a cluster with Kerberos authentication enabled (security mode):
  kinit Component service user
  
  clickhouse client --host IP address of the ClickHouseServer instance that reports the alarm --port 9440 --secure
- For a cluster with Kerberos authentication disabled (normal mode):
  clickhouse client --host IP address of the ClickHouseServer instance that reports the alarm --user Username --password --port 9000
Run the following SQL statement to obtain the shard based on the value of data_path. For example, if the value of data_path is /srv/Bigdata/clickhouse/data1.../shard2_all_replicas, the desired shard is shard2.

select database, table, data_path, data_files, error_count from system.distribution_queue where data_files != 0 and error_count != 0;
Run the following SQL statement to obtain the node IP address (value of the host field in the system table system.clusters) of the shard where data fails to be sent to (shard_num obtained in 3):

select * from system.clusters;
Log in to the ClickHouse node obtained in 4, connect to the server by referring to 2, and run the following statement to check whether the result can be properly returned:

SELECT 1;
- If yes, go to 6.
- If no, go to 7.
Wait for several minutes and check whether the alarm is cleared.
- If yes, no further action is required.
- If no, go to 7.

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 ClickHouse for the target cluster.
Expand the Hosts drop-down list. In the Select Host dialog box that is displayed, select the abnormal host, and click OK.
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.
Contact O&M engineers and provide the collected logs.