Thanks for writing this up, Gábor. As Aljoscha suggested chaining changes all of these and makes it very tricky to work with these which should be clearly documented. That was the reason while some time ago the streaming API always copied the output of a UDF by default to avoid this ambiguous cases. Now this copying is omitted for performance reasons.
On Mon, Dec 14, 2015 at 1:15 PM, Gábor Gévay <gga...@gmail.com> wrote: > I guess chaining happens so often, that we should just write this doc > assuming that there is chaining, and not even describe the rules for > the non-chaining case. I mean I would never risk writing a UDF that > only works when there is no chaining, and then constantly worry about > when do I accidentally introduce chaining. Or what do you think? > > Best, > Gábor > > > > > 2015-12-14 11:33 GMT+01:00 Aljoscha Krettek <aljos...@apache.org>: > > Good write up. You could extend the Table of 1) a/b 2) a/b at the top > with “chaining” (but you already know this, I guess). Chaining changes all > of these and I think it can be tricky to know whether stuff is chained or > not (for users, and even for us developers…). > > > > > >> On 13 Dec 2015, at 19:24, Gábor Gévay <gga...@gmail.com> wrote: > >> > >> Hello, > >> > >> I find the documentation about object reuse [1] very confusing. I > >> started a Google Doc [2] about clarifying/rewriting it. > >> > >> First, it states four questions that I think should have answers > >> stated explicitly in the documentation, and then lists some concrete > >> problems (ambiguities) in the current text. > >> > >> [1] > https://ci.apache.org/projects/flink/flink-docs-master/apis/programming_guide.html#object-reuse-behavior > >> [2] > https://docs.google.com/document/d/1cgkuttvmj4jUonG7E2RdFVjKlfQDm_hE6gvFcgAfzXg/edit?usp=sharing > >> > >> Best, > >> Gabor > > >
