stuhood commented on issue #25483: URL: https://github.com/apache/datafusion/issues/25483#issuecomment-5735243909
@gene-bordegaray: Nice! It seems like this potentially unifies `CoalescePartitionsExec` and `RepartitionExec`, which is awesome?: 1. `CoalescePartitionsExec` is just an `N -> 1` mapping with whole-batch forwarding. 2. It gives us `N -> M` coalescing (`1 < M < N`), which we don't have now (today, reducing partition count forces an all-to-all hash or round-robin repartition). For `SourceFiner`, do you envision executing this via `RepartitionExec` (spawning background tasks with channels), or via direct in-thread stream concatenation (like a generalized `CoalescePartitionsExec`)? If adjacent partitions `S0: (-inf, 10)` and `S1: [10, 20)` are internally sorted, streaming `S0` then `S1` sequentially in-thread preserves total sort order for free without channels, background tasks, or heaps. Routing through `RepartitionExec` channels would interleave them across threads and lose ordering. ---- We ran into this exact distinction between shuffle (`NetworkShuffleExec`) and disjoint task coalescing (`NetworkCoalesceExec`) in DFD: see https://github.com/paradedb/datafusion-distributed/issues/68. -- 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]
