v.21.7New Feature
Add prefer_global_in_and_join boolean setting for IN/JOIN operations
Add a new boolean setting prefer_global_in_and_join which defaults all IN/JOIN as GLOBAL IN/JOIN. #23434 (Amos Bird).Why it matters
This setting addresses the need to optimize query execution in distributed environments by preferring global joins and IN operations by default, which can improve query performance and consistency when working with distributed tables.How to use it
Enable the feature by settingprefer_global_in_and_join = 1 in the ClickHouse server configuration or per session. Once enabled, all IN and JOIN clauses will implicitly use the global variant without needing to specify GLOBAL explicitly in queries.