Dandandan commented on issue #9846: URL: https://github.com/apache/datafusion/issues/9846#issuecomment-2571713705
> > Is there a rule of thumb for choosing SMJ over HJ? > > Is there any plan on re-iterating on the SMJ heuristics ? For example, a use-case of mine would be: input data is pre-sorted + `target_partitions = 1` to use a single CPU core (wonder if there are better knobs that `target_partitions` for this btw). > > This couldn't use SMJ with current heuristics: > > https://github.com/apache/datafusion/blob/f3b1141d0f417e9d9e6c0ada03592c9d9ec60cd4/datafusion/core/src/physical_planner.rs#L1114-L1116 Sounds like that would probably be a good choice. Besides adding a knob / changing the default to do this, I think we will need some examples /benchmarks showing preferring SMJ over hash join in certain situations will improve performance and thus is a sane default. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
