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https://issues.apache.org/jira/browse/FLINK-1319?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14307203#comment-14307203
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Timo Walther commented on FLINK-1319:
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Actually, I don't like the "drop-in" approach. I think it would be much better
if the code analysis can be included in the release. Especially once the code
is stable enough, it would be great to enable it by default and speed up jobs
automatically.
I did some research about other frameworks we could use instead. Soot is the
best framework, however, I think we can also build the code analysis on top of
the ObjectWeb ASM library[1]. It provides some functionality for data flow
analysis[2]. The examples for BasicInterpreter and BasicVerifier look
promising. Other projects use it for determine types[3].
Using ASM requires us to implement more but it gives us full flexibility for
further analysis use cases.
I would try implement a simple proof-of-concept prototype. What do you think?
[1] http://asm.ow2.org/
[2] http://download.forge.objectweb.org/asm/asm4-guide.pdf, 115ff
[3]
https://github.com/hraberg/enumerable/blob/master/src/main/java/org/enumerable/lambda/support/expression/ExpressionInterpreter.java
> Add static code analysis for UDFs
> ---------------------------------
>
> Key: FLINK-1319
> URL: https://issues.apache.org/jira/browse/FLINK-1319
> Project: Flink
> Issue Type: New Feature
> Components: Java API, Scala API
> Reporter: Stephan Ewen
> Assignee: Timo Walther
> Priority: Minor
>
> Flink's Optimizer takes information that tells it for UDFs which fields of
> the input elements are accessed, modified, or frwarded/copied. This
> information frequently helps to reuse partitionings, sorts, etc. It may speed
> up programs significantly, as it can frequently eliminate sorts and shuffles,
> which are costly.
> Right now, users can add lightweight annotations to UDFs to provide this
> information (such as adding {{@ConstandFields("0->3, 1, 2->1")}}.
> We worked with static code analysis of UDFs before, to determine this
> information automatically. This is an incredible feature, as it "magically"
> makes programs faster.
> For record-at-a-time operations (Map, Reduce, FlatMap, Join, Cross), this
> works surprisingly well in many cases. We used the "Soot" toolkit for the
> static code analysis. Unfortunately, Soot is LGPL licensed and thus we did
> not include any of the code so far.
> I propose to add this functionality to Flink, in the form of a drop-in
> addition, to work around the LGPL incompatibility with ALS 2.0. Users could
> simply download a special "flink-code-analysis.jar" and drop it into the
> "lib" folder to enable this functionality. We may even add a script to
> "tools" that downloads that library automatically into the lib folder. This
> should be legally fine, since we do not redistribute LGPL code and only
> dynamically link it (the incompatibility with ASL 2.0 is mainly in the
> patentability, if I remember correctly).
> Prior work on this has been done by [~aljoscha] and [~skunert], which could
> provide a code base to start with.
> *Appendix*
> Hompage to Soot static analysis toolkit: http://www.sable.mcgill.ca/soot/
> Papers on static analysis and for optimization:
> http://stratosphere.eu/assets/papers/EnablingOperatorReorderingSCA_12.pdf and
> http://stratosphere.eu/assets/papers/openingTheBlackBoxes_12.pdf
> Quick introduction to the Optimizer:
> http://stratosphere.eu/assets/papers/2014-VLDBJ_Stratosphere_Overview.pdf
> (Section 6)
> Optimizer for Iterations:
> http://stratosphere.eu/assets/papers/spinningFastIterativeDataFlows_12.pdf
> (Sections 4.3 and 5.3)
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