[ANNOUNCE] Weekly Community Update 2019/31

[Konstantin Knauf-2]

Dear community, 

happy to share this week's community update with news about a Flink on PyPi, code style proposals, Flink 1.9.0 RC1, Flame Graphs in the WebUI and a bit more.

As always, please feel free to add additional updates and news to this thread!

Flink Development

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* [development process] Andrey has opened three threads following up on the recently published "code style and quality guide". They deal with the usage of Java Optional [1] (tl;dr: only as return type in public APIs) , Collections with initial capacity [2] (tl;dr: only if trivial) and how to wrap long arguments lists and chained method calls [3] (tl;dr: yes, but details still open). 

* [python] Jingcheng has started a voting thread on publishing PyFlink to PyPi. Name will be "apache-flink" and the account will be managed by the Apache Flink PMC. The vote has passed unanimously. [4]

* [metrics] David proposed to add a CPU flame graph [5] for each Task to the WebUI (similar to the backpressure monitor). A CPU flame graph is a visualisation method for stack trace samples, which makes it easier to determine hot code paths. This has been well received and David is looking for a comitter to sheperd the effort. [6]

* [releases] Kurt announced a second preview RC (RC1) for Flink 1.9.0 to facilitate ongoing release testing. There will be no vote on this RC. [7]

* [filesystems] Aljoscha proposed to removev flink-mapr-fs module from Apache Flink due to recent problems pulling its dependencies. If removed the MapR filesytem could still be used with Flink's HadoopFilesystem [8]

* [client] Tison has published a first design document on the recently discussed improvements to Flink's client API. [9]

[1] http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-CODE-STYLE-Usage-of-Java-Optional-tp31240.html

[2] http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-CODE-STYLE-Create-collections-always-with-initial-capacity-tp31229.html

[3] http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-CODE-STYLE-Breaking-long-function-argument-lists-and-chained-method-calls-tp31242.html

[4] http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/VOTE-Publish-the-PyFlink-into-PyPI-tp31201.html

[5] http://www.brendangregg.com/FlameGraphs/cpuflamegraphs.html

[6] http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-CPU-flame-graph-for-a-job-vertex-in-web-UI-tp31188.html

[7] http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/PREVIEW-Apache-Flink-1-9-0-release-candidate-1-tp31233.html

[8] http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-Removing-the-flink-mapr-fs-module-tp31080.html

[9] http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-Flink-client-api-enhancement-for-downstream-project-tp25844.html

Notable Bugs

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Nothing for 1.6/1.7/1.8 that came to my attention.

Events, Blog Posts, Misc

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* Nico Kruber published the second part of his series on Flink's network stack. This time about metrics, monitoring and backpressure. (This slipped through last week.) [10]

[10] https://flink.apache.org/2019/07/23/flink-network-stack-2.html

Cheers,

Konstantin (@snntrable)

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