flink-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Stephan Ewen <se...@apache.org>
Subject Re: Need some help to implement the outer join operator
Date Sat, 13 Dec 2014 15:25:57 GMT
Hi Wilson!

You can start by mocking an outer join operator using a special CoGroup
function. If one of the two sides for a group is empty, you have the case
where you need to append null values. Otherwise, you build the Cartesian
produce within the group.

For a proper through-the-stack implementation (not sure if that is needed,
but may be nice to have), have a look here:



On Sat, Dec 13, 2014 at 3:19 AM, Zihong Cao <wilsoncao01@gmail.com> wrote:
> Hi,
> I am trying to pick up the outer join operator. However, as Fabian
> mentioned to me, that this task would require to touch many different
> components of the system, it would be a challenge job for me. Therefore I
> would need some help:-)
> I might need to walk through some features like Compiler/Optimizer and
> Runtime(as Fabian mentioned to me), so where should I start to get familiar?
> One more thing, is the outer join operator implementation similar to the
> pure join operator?
> Best,
> Wilson Cao

  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message