v.20.10Improvement

SYSTEM RELOAD CONFIG Exception Handling Update

SYSTEM RELOAD CONFIG now throws an exception if failed to reload and continues using the previous users.xml. The background periodic reloading also continues using the previous users.xml if failed to reload. #14492 (Vitaly Baranov).
SYSTEM RELOAD CONFIG now throws an exception if reloading users.xml fails, preserving the previous configuration.

Why it matters

This feature ensures that if reloading the user configuration file users.xml fails, the system does not silently continue with a bad state but instead raises an exception and keeps the previous valid configuration, improving reliability and observability.

How to use it

Use the SYSTEM RELOAD CONFIG command to reload the users.xml configuration. If the reload fails, an exception will be thrown and the previous configuration will remain active. The background periodic configuration reload also maintains the last valid configuration on failure automatically.