Hi Aljoscha,
That's a good points, so far, most of the code will live in flink-python
module, and the rules and relNodes will be put into the both blink and
flink planner modules, some of the common interface of required by planners
will be placed in flink-table-common. I think you are right, we should try
to ensure the changes of this feature is minimal. For more detail we would
follow this principle when review the PRs.
Great thanks for your questions and remind!
Best,
Jincheng
Aljoscha Krettek <aljos...@apache.org> 于2019年9月4日周三 下午8:58写道：
> Hi,
>
> Things looks interesting so far!
>
> I had one question: Where will most of the support code for this live?
> Will this add the required code to flink-table-common or the different
> runners? Can we implement this in such a way that only a minimal amount of
> support code is required in the parts of the Table API (and Table API
> runners) that are not python specific?
>
> Best,
> Aljoscha
>
> > On 4. Sep 2019, at 14:14, Timo Walther <twal...@apache.org> wrote:
> >
> > Hi Jincheng,
> >
> > 2. Serializability of functions: "#2 is very convenient for users" means
> only until they have the first backwards-compatibility issue, after that
> they will find it not so convinient anymore and will ask why the framework
> allowed storing such objects in a persistent storage. I don't want to be
> picky about it, but wanted to raise awareness that sometimes it is ok to
> limit use cases to guide users for devloping backwards-compatible programs.
> >
> > Thanks for the explanation fo the remaining items. It sounds reasonable
> to me. Regarding the example with `getKind()`, I actually meant
> `org.apache.flink.table.functions.ScalarFunction#getKind` we don't allow
> users to override this property. And I think we should do something similar
> for the getLanguage property.
> >
> > Thanks,
> > Timo
> >
> > On 03.09.19 15:01, jincheng sun wrote:
> >> Hi Timo,
> >>
> >> Thanks for the quick reply ! :)
> >> I have added more example for #3 and #5 to the FLIP. That are great
> >> suggestions !
> >>
> >> Regarding 2:
> >>
> >> There are two kind Serialization for CloudPickle(Which is different from
> >> Java):
> >> 1) For class and function which can be imported, CloudPickle only
> >> serialize the full path of the class and function (just like java class
> >> name).
> >> 2) For the class and function which can not be imported, CloudPickle
> will
> >> serialize the full content of the class and function.
> >> For #2, It means that we can not just store the full path of the class
> and
> >> function.
> >>
> >> The above serialization is recursive.
> >>
> >> However, there is indeed an problem of backwards compatibility when the
> >> module path of the parent class changed. But I think this is an rare
> case
> >> and acceptable. i.e., For Flink framework we never change the user
> >> interface module path if we want to keep backwards compatibility. For
> user
> >> code, if they change the interface of UDF's parent, they should
> re-register
> >> their functions.
> >>
> >> If we do not want support #2, we can store the full path of class and
> >> function, in that case we have no backwards compatibility problem. But I
> >> think the #2 is very convenient for users.
> >>
> >> What do you think?
> >>
> >> Regarding 4:
> >> As I mentioned earlier, there may be built-in Python functions and I
> think
> >> language is a "function" concept. Function and Language are orthogonal
> >> concepts.
> >> We may have R, GO and other language functions in the future, not only
> >> user-defined, but also built-in functions.
> >>
> >> You are right that users will not set this method and for Python
> functions,
> >> it will be set in the code-generated Java function by the framework.
> So, I
> >> think we should declare the getLanguage() in FunctionDefinition for now.
> >> (I'm not pretty sure what do you mean by saying that getKind() is final
> in
> >> UserDefinedFunction?)
> >>
> >> Best,
> >> Jincheng
> >>
> >> Timo Walther <twal...@apache.org> 于2019年9月3日周二 下午6:01写道：
> >>
> >>> Hi Jincheng,
> >>>
> >>> thanks for your response.
> >>>
> >>> 2. Serializability of functions: Using some arbitrary serialization
> >>> format for shipping a function to worker sounds fine to me. But once we
> >>> store functions a the catalog we need to think about backwards
> >>> compatibility and evolution of interfaces etc. I'm not sure if
> >>> CloudPickle is the right long-term storage format for this. If we don't
> >>> think about this in advance, we are basically violating our code
> quality
> >>> guide [1] of never use Java Serialization but in the Python-way. We are
> >>> using the RPC serialization for persistence.
> >>>
> >>> 3. TableEnvironment: Can you add some example to the FLIP? Because API
> >>> code like the following is not covered there:
> >>>
> >>> self.t_env.register_function("add_one", udf(lambda i: i + 1,
> >>> DataTypes.BIGINT(),
> >>> DataTypes.BIGINT()))
> >>> self.t_env.register_function("subtract_one", udf(SubtractOne(),
> >>> DataTypes.BIGINT(),
> >>> DataTypes.BIGINT()))
> >>> self.t_env.register_function("add", add)
> >>>
> >>> 4. FunctionDefinition: Your response still doesn't answer my question
> >>> entirely. Why do we need FunctionDefinition.getLanguage() if this is a
> >>> "user-defined function" concept and not a "function" concept. In any
> >>> case, all users should not be able to set this method. So it must be
> >>> final in UserDefinedFunction similar to getKind().
> >>>
> >>> 5. Function characteristics: If UserDefinedFunction is defined in
> >>> Python, why is it not used in your example in FLIP-58. You could you
> >>> extend the example to show how to specify these attributes in the FLIP?
> >>>
> >>> Regards,
> >>> Timo
> >>>
> >>> [1]
> https://flink.apache.org/contributing/code-style-and-quality-java.html
> >>>
> >>> On 02.09.19 15:35, jincheng sun wrote:
> >>>> Hi Timo,
> >>>>
> >>>> Great thanks for your feedback. I would like to share my thoughts with
> >>> you
> >>>> inline. :)
> >>>>
> >>>> Best,
> >>>> Jincheng
> >>>>
> >>>> Timo Walther <twal...@apache.org> 于2019年9月2日周一 下午5:04写道：
> >>>>
> >>>>> Hi all,
> >>>>>
> >>>>> the FLIP looks awesome. However, I would like to discuss the changes
> to
> >>>>> the user-facing parts again. Some feedback:
> >>>>>
> >>>>> 1. DataViews: With the current non-annotation design for DataViews,
> we
> >>>>> cannot perform eager state declaration, right? At which point during
> >>>>> execution do we know which state is required by the function? We
> need to
> >>>>> instantiate the function first, right?
> >>>>>
> >>>>>> We will analysis the Python AggregateFunction and extract the
> DataViews
> >>>> used in the Python AggregateFunction. This can be done
> >>>> by instantiate a Python AggregateFunction, creating an accumulator by
> >>>> calling method create_accumulator and then analysis the created
> >>>> accumulator. This is actually similar to the way that Java
> >>>> AggregateFunction processing codegen logic. The extracted DataViews
> can
> >>>> then be used to construct the StateDescriptors in the operator, i.e.,
> we
> >>>> should have hold the state spec and the state descriptor id in Java
> >>>> operator and Python worker can access the state by specifying the
> >>>> corresponding state descriptor id.
> >>>>
> >>>>
> >>>>
> >>>>> 2. Serializability of functions: How do we ensure serializability of
> >>>>> functions for catalog persistence? In the Scala/Java API, we would
> like
> >>>>> to register classes instead of instances soon. This is the only way
> to
> >>>>> store a function properly in a catalog or we need some
> >>>>> serialization/deserialization logic in the function interfaces to
> >>>>> convert an instance to string properties.
> >>>>>
> >>>>>> The Python function will be serialized with CloudPickle anyway in
> the
> >>>> Python API as we need to transfer it to the Python worker which can
> then
> >>>> deserialize it for execution. The serialized Python function can be
> >>> stored
> >>>> into catalog.
> >>>>
> >>>>
> >>>>
> >>>>> 3. TableEnvironment: What is the signature of
> `register_function(self,
> >>>>> name, function)`? Does it accept both a class and function? Like
> `class
> >>>>> Sum` and `def split()`? Could you add some examples for registering
> both
> >>>>> kinds of functions?
> >>>>>
> >>>>>> It has been already supported which you mentioned. You can find an
> >>>> example in the POC code:
> >>>>
> >>>
> https://github.com/dianfu/flink/commit/93f41ba173482226af7513fdec5acba72b274489#diff-34f619b31a7e38604e22a42a441fbe2fR26
> >>>>
> >>>>
> >>>>> 4. FunctionDefinition: Function definition is not a user-defined
> >>>>> function definition. It is the highest interface for both
> user-defined
> >>>>> and built-in functions. I'm not sure if getLanguage() should be part
> of
> >>>>> this interface or one-level down which would be
> `UserDefinedFunction`.
> >>>>> Built-in functions will never be implemented in a different
> language. In
> >>>>> any case, I would vote for removing the UNKNOWN language, because it
> >>>>> does not solve anything. Why should a user declare a function that
> the
> >>>>> runtime can not handle? I also find the term `JAVA` confusing for
> Scala
> >>>>> users. How about `FunctionLanguage.JVM` instead?
> >>>>>
> >>>>>> Actually we may have built-in Python functions in the future.
> Regarding
> >>>> to the following expression: py_udf1(a, b) + py_udf2(c), if there is
> >>>> built-in Python
> >>>> funciton for '+' operator, then we don't need to mix using Java and
> >>> Python
> >>>> UDFs. In this way, we can improve the execution performance.
> >>>> Regarding to removing FunctionLanguage.UNKNOWN and renaming
> >>>> FunctionLanguage.Java to FunctionLanguage.JVM, it makes more sense to
> me.
> >>>>
> >>>>
> >>>>
> >>>>> 5. Function characteristics: In the current design, function classes
> do
> >>>>> not extend from any upper class. How can users declare
> characteristics
> >>>>> that are present in `FunctionDefinition` like determinism,
> requirements,
> >>>>> or soon also monotonism.
> >>>>>
> >>>>>> Actually we have defined 'UserDefinedFunction' which is the base
> class
> >>>> for all user-defined functions.
> >>>> We can define the deterministic, requirements, etc in this class.
> >>>> Currently, we have already supported to define the deterministic.
> >>>>
> >>>>
> >>>>
> >>>>> Thanks,
> >>>>> Timo
> >>>>>
> >>>>>
> >>>>> On 02.09.19 03:38, Shaoxuan Wang wrote:
> >>>>>> Hi Jincheng, Fudian, and Aljoscha,
> >>>>>> I am assuming the proposed python UDX can also be applied to Flink
> SQL.
> >>>>>> Is this correct? If yes, I would suggest to title the FLIP as "Flink
> >>>>> Python
> >>>>>> User-Defined Function" or "Flink Python User-Defined Function for
> >>> Table".
> >>>>>> Regards,
> >>>>>> Shaoxuan
> >>>>>>
> >>>>>>
> >>>>>> On Wed, Aug 28, 2019 at 12:22 PM jincheng sun <
> >>> sunjincheng...@gmail.com>
> >>>>>> wrote:
> >>>>>>
> >>>>>>> Thanks for the feedback Bowen!
> >>>>>>>
> >>>>>>> Great thanks for create the FLIP and bring up the VOTE Dian!
> >>>>>>>
> >>>>>>> Best, Jincheng
> >>>>>>>
> >>>>>>> Dian Fu <dian0511...@gmail.com> 于2019年8月28日周三 上午11:32写道：
> >>>>>>>
> >>>>>>>> Hi all,
> >>>>>>>>
> >>>>>>>> I have started a voting thread [1]. Thanks a lot for your help
> during
> >>>>>>>> creating the FLIP @Jincheng.
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> Hi Bowen,
> >>>>>>>>
> >>>>>>>> Very appreciated for your comments. I have replied you in the
> design
> >>>>> doc.
> >>>>>>>> As it seems that the comments doesn't affect the overall design,
> I'll
> >>>>> not
> >>>>>>>> cancel the vote for now and we can continue the discussion in the
> >>>>> design
> >>>>>>>> doc.
> >>>>>>>>
> >>>>>>>> [1]
> >>>>>>>>
> >>>
> http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/VOTE-FLIP-58-Flink-Python-User-Defined-Function-for-Table-API-td32295.html
> >>>>>>>> <
> >>>>>>>>
> >>>
> http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/VOTE-FLIP-58-Flink-Python-User-Defined-Function-for-Table-API-td32295.html
> >>>>>>>> Regards,
> >>>>>>>> Dian
> >>>>>>>>
> >>>>>>>>> 在 2019年8月28日，上午11:05，Bowen Li <bowenl...@gmail.com> 写道：
> >>>>>>>>>
> >>>>>>>>> Hi Jincheng and Dian,
> >>>>>>>>>
> >>>>>>>>> Sorry for being late to the party. I took a glance at the
> proposal,
> >>>>>>> LGTM
> >>>>>>>> in
> >>>>>>>>> general, and I left only a couple comments.
> >>>>>>>>>
> >>>>>>>>> Thanks,
> >>>>>>>>> Bowen
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> On Mon, Aug 26, 2019 at 8:05 PM Dian Fu <dian0511...@gmail.com>
> >>>>> wrote:
> >>>>>>>>>> Hi Jincheng,
> >>>>>>>>>>
> >>>>>>>>>> Thanks! It works.
> >>>>>>>>>>
> >>>>>>>>>> Thanks,
> >>>>>>>>>> Dian
> >>>>>>>>>>
> >>>>>>>>>>> 在 2019年8月27日，上午10:55，jincheng sun <sunjincheng...@gmail.com>
> 写道：
> >>>>>>>>>>>
> >>>>>>>>>>> Hi Dian, can you check if you have edit access? :)
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>> Dian Fu <dian0511...@gmail.com> 于2019年8月26日周一 上午10:52写道：
> >>>>>>>>>>>
> >>>>>>>>>>>> Hi Jincheng,
> >>>>>>>>>>>>
> >>>>>>>>>>>> Appreciated for the kind tips and offering of help. Definitely
> >>> need
> >>>>>>>> it!
> >>>>>>>>>>>> Could you grant me write permission for confluence? My Id:
> Dian
> >>> Fu
> >>>>>>>>>>>> Thanks,
> >>>>>>>>>>>> Dian
> >>>>>>>>>>>>
> >>>>>>>>>>>>> 在 2019年8月26日，上午9:53，jincheng sun <sunjincheng...@gmail.com>
> 写道：
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Thanks for your feedback Hequn & Dian.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Dian, I am glad to see that you want help to create the FLIP!
> >>>>>>>>>>>>> Everyone will have first time, and I am very willing to help
> you
> >>>>>>>>>> complete
> >>>>>>>>>>>>> your first FLIP creation. Here some tips:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> - First I'll give your account write permission for
> confluence.
> >>>>>>>>>>>>> - Before create the FLIP, please have look at the FLIP
> Template
> >>>>>>> [1],
> >>>>>>>>>>>> (It's
> >>>>>>>>>>>>> better to know more about FLIP by reading [2])
> >>>>>>>>>>>>> - Create Flink Python UDFs related JIRAs after completing the
> >>> VOTE
> >>>>>>> of
> >>>>>>>>>>>>> FLIP.(I think you also can bring up the VOTE thread, if you
> >>> want!
> >>>>> )
> >>>>>>>>>>>>> Any problems you encounter during this period，feel free to
> tell
> >>> me
> >>>>>>>> that
> >>>>>>>>>>>> we
> >>>>>>>>>>>>> can solve them together. :)
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Best,
> >>>>>>>>>>>>> Jincheng
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> [1]
> >>>>>>> https://cwiki.apache.org/confluence/display/FLINK/FLIP+Template
> >>>>>>>>>>>>> [2]
> >>>>>>>>>>>>>
> >>>
> https://cwiki.apache.org/confluence/display/FLINK/Flink+Improvement+Proposals
> >>>>>>>>>>>>> Hequn Cheng <chenghe...@gmail.com> 于2019年8月23日周五 上午11:54写道：
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> +1 for starting the vote.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Thanks Jincheng a lot for the discussion.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Best, Hequn
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> On Fri, Aug 23, 2019 at 10:06 AM Dian Fu <
> >>> dian0511...@gmail.com>
> >>>>>>>>>> wrote:
> >>>>>>>>>>>>>>> Hi Jincheng,
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> +1 to start the FLIP create and VOTE on this feature. I'm
> >>>>> willing
> >>>>>>>> to
> >>>>>>>>>>>> help
> >>>>>>>>>>>>>>> on the FLIP create if you don't mind. As I haven't created
> a
> >>>>> FLIP
> >>>>>>>>>>>> before,
> >>>>>>>>>>>>>>> it will be great if you could help on this. :)
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> Regards,
> >>>>>>>>>>>>>>> Dian
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> 在 2019年8月22日，下午11:41，jincheng sun <
> sunjincheng...@gmail.com>
> >>>>>>> 写道：
> >>>>>>>>>>>>>>>> Hi all,
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> Thanks a lot for your feedback. If there are no more
> >>>>> suggestions
> >>>>>>>> and
> >>>>>>>>>>>>>>>> comments, I think it's better to initiate a vote to
> create a
> >>>>>>> FLIP
> >>>>>>>>>> for
> >>>>>>>>>>>>>>>> Apache Flink Python UDFs.
> >>>>>>>>>>>>>>>> What do you think?
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> Best, Jincheng
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> jincheng sun <sunjincheng...@gmail.com> 于2019年8月15日周四
> >>>>>>> 上午12:54写道：
> >>>>>>>>>>>>>>>>> Hi Thomas,
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> Thanks for your confirmation and the very important
> reminder
> >>>>>>>> about
> >>>>>>>>>>>>>>> bundle
> >>>>>>>>>>>>>>>>> processing.
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> I have had add the description about how to perform
> bundle
> >>>>>>>>>> processing
> >>>>>>>>>>>>>>> from
> >>>>>>>>>>>>>>>>> the perspective of checkpoint and watermark. Feel free to
> >>>>> leave
> >>>>>>>>>>>>>>> comments if
> >>>>>>>>>>>>>>>>> there are anything not describe clearly.
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> Best,
> >>>>>>>>>>>>>>>>> Jincheng
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> Dian Fu <dian0511...@gmail.com> 于2019年8月14日周三 上午10:08写道：
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> Hi Thomas,
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> Thanks a lot the suggestions.
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> Regarding to bundle processing, there is a section
> >>>>>>>> "Checkpoint"[1]
> >>>>>>>>>>>> in
> >>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>> design doc which talks about how to handle the
> checkpoint.
> >>>>>>>>>>>>>>>>>> However, I think you are right that we should talk more
> >>> about
> >>>>>>>> it,
> >>>>>>>>>>>>>> such
> >>>>>>>>>>>>>>> as
> >>>>>>>>>>>>>>>>>> what's bundle processing, how it affects the checkpoint
> and
> >>>>>>>>>>>>>> watermark,
> >>>>>>>>>>>>>>> how
> >>>>>>>>>>>>>>>>>> to handle the checkpoint and watermark, etc.
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> [1]
> >>>>>>>>>>>>>>>>>>
> >>>
> https://docs.google.com/document/d/1WpTyCXAQh8Jr2yWfz7MWCD2-lou05QaQFb810ZvTefY/edit#heading=h.urladt565yo3
> >>>>>>>>>>>>>>>>>> <
> >>>>>>>>>>>>>>>>>>
> >>>
> https://docs.google.com/document/d/1WpTyCXAQh8Jr2yWfz7MWCD2-lou05QaQFb810ZvTefY/edit#heading=h.urladt565yo3
> >>>>>>>>>>>>>>>>>> Regards,
> >>>>>>>>>>>>>>>>>> Dian
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>> 在 2019年8月14日，上午1:01，Thomas Weise <t...@apache.org> 写道：
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>> Hi Jincheng,
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>> Thanks for putting this together. The proposal is very
> >>>>>>>> detailed,
> >>>>>>>>>>>>>>>>>> thorough
> >>>>>>>>>>>>>>>>>>> and for me as a Beam Flink runner contributor easy to
> >>>>>>>> understand
> >>>>>>>>>> :)
> >>>>>>>>>>>>>>>>>>> One thing that you should probably detail more is the
> >>> bundle
> >>>>>>>>>>>>>>>>>> processing. It
> >>>>>>>>>>>>>>>>>>> is critically important for performance that multiple
> >>>>>>> elements
> >>>>>>>>>> are
> >>>>>>>>>>>>>>>>>>> processed in a bundle. The default bundle size in the
> >>> Flink
> >>>>>>>>>> runner
> >>>>>>>>>>>>>> is
> >>>>>>>>>>>>>>>>>> 1s or
> >>>>>>>>>>>>>>>>>>> 1000 elements, whichever comes first. And for
> streaming,
> >>> you
> >>>>>>>> can
> >>>>>>>>>>>>>> find
> >>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>> logic necessary to align the bundle processing with
> >>>>>>> watermarks
> >>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>> checkpointing here:
> >>>>>>>>>>>>>>>>>>>
> >>>
> https://github.com/apache/beam/blob/release-2.14.0/runners/flink/src/main/java/org/apache/beam/runners/flink/translation/wrappers/streaming/ExecutableStageDoFnOperator.java
> >>>>>>>>>>>>>>>>>>> Thomas
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>> On Tue, Aug 13, 2019 at 7:05 AM jincheng sun <
> >>>>>>>>>>>>>>> sunjincheng...@gmail.com>
> >>>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> Hi all,
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> The Python Table API(without Python UDF support) has
> >>>>> already
> >>>>>>>>>> been
> >>>>>>>>>>>>>>>>>> supported
> >>>>>>>>>>>>>>>>>>>> and will be available in the coming release 1.9.
> >>>>>>>>>>>>>>>>>>>> As Python UDF is very important for Python users, we'd
> >>> like
> >>>>>>> to
> >>>>>>>>>>>>>> start
> >>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>> discussion about the Python UDF support in the Python
> >>> Table
> >>>>>>>> API.
> >>>>>>>>>>>>>>>>>>>> Aljoscha Krettek, Dian Fu and I have discussed offline
> >>> and
> >>>>>>>> have
> >>>>>>>>>>>>>>>>>> drafted a
> >>>>>>>>>>>>>>>>>>>> design doc[1]. It includes the following items:
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> - The user-defined function interfaces.
> >>>>>>>>>>>>>>>>>>>> - The user-defined function execution architecture.
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> As mentioned by many guys in the previous discussion
> >>>>>>>> thread[2],
> >>>>>>>>>> a
> >>>>>>>>>>>>>>>>>>>> portability framework was introduced in Apache Beam in
> >>>>>>> latest
> >>>>>>>>>>>>>>>>>> releases. It
> >>>>>>>>>>>>>>>>>>>> provides well-defined, language-neutral data
> structures
> >>> and
> >>>>>>>>>>>>>> protocols
> >>>>>>>>>>>>>>>>>> for
> >>>>>>>>>>>>>>>>>>>> language-neutral user-defined function execution. This
> >>>>>>> design
> >>>>>>>> is
> >>>>>>>>>>>>>>> based
> >>>>>>>>>>>>>>>>>> on
> >>>>>>>>>>>>>>>>>>>> Beam's portability framework. We will introduce how to
> >>> make
> >>>>>>>> use
> >>>>>>>>>> of
> >>>>>>>>>>>>>>>>>> Beam's
> >>>>>>>>>>>>>>>>>>>> portability framework for user-defined function
> >>> execution:
> >>>>>>>> data
> >>>>>>>>>>>>>>>>>>>> transmission, state access, checkpoint, metrics,
> logging,
> >>>>>>> etc.
> >>>>>>>>>>>>>>>>>>>> Considering that the design relies on Beam's
> portability
> >>>>>>>>>> framework
> >>>>>>>>>>>>>>> for
> >>>>>>>>>>>>>>>>>>>> Python user-defined function execution and not all the
> >>>>>>>>>>>> contributors
> >>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>> Flink community are familiar with Beam's portability
> >>>>>>>> framework,
> >>>>>>>>>> we
> >>>>>>>>>>>>>>> have
> >>>>>>>>>>>>>>>>>>>> done a prototype[3] for proof of concept and also
> ease of
> >>>>>>>>>>>>>>>>>> understanding of
> >>>>>>>>>>>>>>>>>>>> the design.
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> Welcome any feedback.
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> Best,
> >>>>>>>>>>>>>>>>>>>> Jincheng
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> [1]
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>
> >>>
> https://docs.google.com/document/d/1WpTyCXAQh8Jr2yWfz7MWCD2-lou05QaQFb810ZvTefY/edit?usp=sharing
> >>>>>>>>>>>>>>>>>>>> [2]
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>
> >>>
> http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-FLIP-38-Support-python-language-in-flink-TableAPI-td28061.html
> >>>>>>>>>>>>>>>>>>>> [3] https://github.com/dianfu/flink/commits/udf_poc
> >>>>>>>>>>>>>>>>>>>>
> >>>
> >
>
>
