v.22.11Improvement

Implement Default read-in-order Optimization in Query Plan

Official CH changelog text
Implement read-in-order optimization on top of query plan. It is enabled by default. Set query_plan_read_in_order = 0 to use previous AST-based version. #42829 (Nikolai Kochetov).
Implemented a new read-in-order optimization at the query plan level, enabled by default to improve query execution efficiency.

Why it matters

This feature replaces the previous AST-based read-in-order optimization with a more effective query plan-based approach. It aims to enhance query performance by optimizing the order in which data is read, benefiting users with faster and more efficient query processing.

How to use it

The new read-in-order optimization is enabled by default. To revert to the previous AST-based behavior, set the setting query_plan_read_in_order = 0 in your query or configuration.

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