v.23.11Improvement

Plan-level optimizations can now be individually enabled/disabled in ClickHouse

Plan-level optimizations can now be enabled/disabled individually. Previously, it was only possible to disable them all. The setting which previously did that (query_plan_enable_optimizations) is retained and can still be used to disable all optimizations. #57152 (Robert Schulze).
ClickHouse now allows enabling or disabling individual plan-level optimizations instead of toggling all optimizations collectively using a single setting.

Why it matters

This feature provides finer control over query plan optimizations, enabling users to selectively disable or enable specific optimizations. This improves flexibility for debugging, performance tuning, and troubleshooting by isolating the impact of particular optimizations without turning off all of them.

How to use it

Users can control individual plan-level optimizations via new specific settings for each optimization, while the existing query_plan_enable_optimizations setting remains available to enable or disable all optimizations at once.