v.20.4Performance Improvement
Use Single Row Counter for Multiple Streams in Pre-Limit Transform
Use single row counter for multiple streams in pre-limit transform. This helps to avoid uniting pipeline streams in queries withlimitbut withoutorder by(likeselect f(x) from (select x from t limit 1000000000)) and use multiple threads for further processing. #9602 (Nikolai Kochetov)