v.22.5Improvement
Add Warning for ClickHouse Log Level "Test" Due to Severe Performance Issues
Add a warning if someone running clickhouse-server with log level "test". The log level "test" was added recently and cannot be used in production due to inevitable, unavoidable, fatal and life-threatening performance degradation. #36824 (Alexey Milovidov).
Why it matters
The log level "test" causes severe and unavoidable performance degradation, making it unsuitable for production environments. This warning helps prevent accidental usage and potential system issues.How to use it
When startingclickhouse-server, avoid setting the log level to "test". If currently using this log level for testing, switch to a supported log level such as "information" or "debug" to ensure stable performance.