v.22.9Improvement

Add Configuration to Limit FixedString Column Size to 256

Add a setting allow_suspicious_fixed_string_types to prevent users from creating columns of type FixedString with size > 256. #41495 (Duc Canh Le).
Introduces the allow_suspicious_fixed_string_types setting to restrict creation of FixedString columns with size greater than 256.

Why it matters

This feature helps prevent accidental or potentially problematic usage of FixedString data types with very large sizes, which can lead to inefficient storage and performance issues. By limiting the size to 256, it encourages better schema design and resource management.

How to use it

Enable or disable the feature by setting the allow_suspicious_fixed_string_types setting. To prevent creating columns with FixedString size > 256, ensure this setting is set to 0. For example, use SET allow_suspicious_fixed_string_types = 0; before creating the table or define it in the server configuration.