v.20.8Improvement

Avoid Slow Queries on Array Manipulations in ClickHouse

Avoid too slow queries when arrays are manipulated as fields. Throw exception instead. #13753 (alexey-milovidov).
ClickHouse now throws an exception for queries that manipulate arrays as fields when such operations would be too slow, preventing excessively long query execution times.

Why it matters

This feature aims to avoid performance degradation caused by inefficient array manipulations in queries. By detecting potentially slow array operations early and throwing an exception, it helps users avoid long-running queries that could negatively impact system responsiveness and resource usage.

How to use it

No explicit user action is required to enable this feature. When a query involves arrays as fields and the operation is detected to be too slow, ClickHouse will automatically throw an exception to prevent the query from running excessively long.