v.20.1Improvement

SYSTEM RELOAD DICTIONARY Executes Synchronously

SYSTEM RELOAD DICTIONARY now executes synchronously. #8240 (Vitaly Baranov)
SYSTEM RELOAD DICTIONARY command now executes synchronously in ClickHouse.

Why it matters

Previously, the SYSTEM RELOAD DICTIONARY command may have executed asynchronously, which could lead to uncertainty about when the dictionary data was actually refreshed. Making it synchronous ensures that the dictionary reload completes before the command returns, providing users with a clear guarantee that subsequent queries will see the updated dictionary data immediately.

How to use it

To reload a dictionary synchronously, simply execute the SYSTEM RELOAD DICTIONARY dict_name command as usual. The command will now block and complete only after the dictionary has been fully reloaded.