Collecting Dumping Logs of the ClickHouse System Tables

This section applies only to MRS 3.3.0-LTS or later.

Scenario

If an exception occurs, you need to restart ClickHouse to restore services. Before restart, you need to dump the status information of each ClickHouse system table for efficient ClickHouse fault locating.

System table logs can be dumped in real time or in one-click mode, as shown in the following table.

Log Dumping Type	System Tables
Real-time dumping	system.asynchronous_metrics system.clusters system.distribution_queue system.events system.grants system.mutations system.processes system.metrics system.part_moves_between_shards system.replicas system.replicated_fetches system.replication_queue
One-click dumping	system.distributed_ddl_queue system.errors system.parts system.parts_columns system.query_log system.query_thread_log system.trace_log

Collecting Real-Time Dumping Logs

Log in to FusionInsight Manager, choose O&M > Log > Download, and select ClickHouseSystemTableDump for Service.
Select the hosts where you want to collect dumping logs and click OK.
Click the time editing button in the upper right corner and set Start Time and End Time for log collection.

For details about how long it takes to collect logs, contact technical support engineers.
Click Download. The real-time system table dumping logs are saved to the local PC.

Collecting One-Click Dumping Logs

Log in to any ClickHouseServer node as the root user and go to the sbin directory.
cd ${BIGDATA_HOME}/FusionInsight_ClickHouse_*/*_*_ClickHouseServer/install/clickhouse/sbin
Run the following command to obtain dumping logs:
./clickhouse_systemtable_dump.sh 1 "Start time" "End time"

Example: ./clickhouse_systemtable_dump.sh 1 "2023-08-04 12:00:00" "2023-08-04 16:37:20"
Go to the /var/log/Bigdata/clickhouse/systemTableDump/oneclickTable directory and view the compressed one-click dumping logs.