Capturing server logs of queries at the client

Learn how to capture server logs at the client level, even with different log settings, using the send_logs_level client setting.

Learn how to capture server logs of queries at the client.

A client can view the server logs - even at a different level than what the server log level is configured to - by setting the send_logs_level client setting.

For example, suppose the client runs:

SET send_logs_level = 'trace';

The client will receive trace logs even if the server has log level set to info.

One useful scenario is to use send_logs_level to monitor the insertion of rows into a Distributed table:

• Enable logs in clickhouse-client using SET send_logs_level = 'trace';
• Run your INSERT query
• Inserts into a distributed table are asynchronous by default. The data is written into a local buffer on disk, then sent to remote servers in background.
• Logs will be sent from all nodes participating in the query processing (distributed tracing)

To check the status of distributed inserts, check the system.distribution_queue table. This table contains information about local files that are in the queue to be sent to the shards. These local files contain new parts that are created by inserting new data into the Distributed table in asynchronous mode.