Join

[BohuTANG]

Summary
Initial tasks:

• join sql parser (almost done, but need to convert to plan)
• join plan
• join transform(hash)
• reshuffle mode
  • FuseQuery reshuffle: Reshuffle transform
    1. a unified reshuffle transform that can be used for group-by or others who needs reshuffle
  • FuseStorage reshuffle?
    1. push down a hash expression to storage, like join_key_a%5=3 AND join_key_b%5=3
    2. FuseQuery node do local join
    3. FuseQuery do final merge

[leiysky]

I'd like to write a RFC for join recently. Is there already any plan on this?

[BohuTANG]

Cool, it's not started yet, welcome RFC

[leiysky]

I just wrote a draft proposal #465, welcome to comment.

By the way, I found it's hard to discuss about the detailed part in this RFC. Thus I'm going to write another RFC about implementation of hash join algorithm.

[BohuTANG]

021-05-01-join-framework-design.md moved to website/datafuse/docs/rfcs at #501
Cc @leiysky

[Xuanwo]

Join has been supported, closing.