Several operators in DuckDB exhibit non-deterministic behavior. Most notably, SQL uses set semantics, which allows results to be returned in a different order. DuckDB exploits this to improve performance, particularly when performing multi-threaded query execution. Other factors, such as using different compilers, operating systems, and hardware architectures, can also cause changes in ordering. This page documents the cases where non-determinism is an expected behavior. If you would like to ...
