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https://issues.apache.org/jira/browse/FLINK-1319?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14562523#comment-14562523
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ASF GitHub Bot commented on FLINK-1319:
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Github user twalthr commented on the pull request:
https://github.com/apache/flink/pull/729#issuecomment-106233384
I disabled the analyzer for all classes starting with "org.apache.flink".
Because I wanted to reduce the output to the user for build-in UDFs (e.g.
`org.apache.flink.api.java.Utils$CollectHelper` or UDFs within the Graph API).
Initially I thought about an annotation `@SkipCodeAnalysis` but there are too
many UDFs where this annotation should then be placed at. I think we can assume
that UDFs shipped with Flink are already implemented effcient or unefficient
for example purposes only.
Object creations "in method" mean that these objects are created directly
in e.g. `map()`. The analyzer also follows method calls. "transitively" created
objects are objects created in the nested method calls.
> 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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