Slack digest for #general - 2018-10-09

[Apache Pulsar Slack <ap...@gmail.com>]

2018-10-08 10:16:05 UTC - dba: @Sijie Guo True, but there is still only one instance of Pulsar? Anyway, I found the problem, I had to: ./pulsar-admin namespaces set-clusters public/mytest --clusters standalone
With that done I can have topics created automatically in my namespace.
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2018-10-08 10:17:21 UTC - dba: It solved the problem, thanks!
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2018-10-08 10:18:24 UTC - Steven King: Glad it helped :thumbsup:
+1 : dba
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2018-10-08 10:32:34 UTC - Assaf Lavi: @Assaf Lavi has joined the channel
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2018-10-08 10:52:25 UTC - hj: @hj has joined the channel
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2018-10-08 11:17:13 UTC - hj: how to use pulsar function to average temperature of 1 minute per device
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2018-10-08 13:43:08 UTC - Jean-Bernard van Zuylen: Hi all,
When using the Pulsar Client with Apache Tomcat, on shutdown the process will hang. All (utility) threads started by the client (timer, client-io, external-listener) are non-daemon threads preventing Tomcat to exit nicely. Normally threads should inherit the daemon status of its parent thread (unless the daemon flag is set of course). It's seems that issue comes from the `DefaultThreadFactory` from the Netty library which creates by default non-daemon threads. I would like a propose a patch for this situation. Would you be interested and what would be the best option?
- Apply default from Java and have threads inherit the daemon from its parent
- Add an option to the `ClientBuilder`, called `workerThreadsAsDeamon(boolean workerThreadsAsDeamon)`, default would `false` to keep the current behavior
I know using daemon threads might seem inconvenient in case of I/O but with the help of Shutdown Hooks, developers can make sure to close the Pulsar Client properly when the JVM is shutting down
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2018-10-08 13:44:31 UTC - Sanjeev Kulkarni: @hj use the windowing mechanism that’s available with java functions 
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2018-10-08 13:45:43 UTC - Sanjeev Kulkarni: <https://github.com/apache/pulsar/blob/master/pulsar-functions/java-examples/src/main/java/org/apache/pulsar/functions/api/examples/CommaWindowFunction.java>
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2018-10-08 13:46:25 UTC - Sanjeev Kulkarni: <https://github.com/apache/pulsar/blob/master/pulsar-functions/java-examples/src/main/java/org/apache/pulsar/functions/api/examples/WindowDurationFunction.java>
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2018-10-08 13:46:46 UTC - Sanjeev Kulkarni: These are couple examples that illustrate how to program window functions
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2018-10-08 13:52:54 UTC - Shalin: @Matteo Merli
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2018-10-08 17:03:02 UTC - William Fry: cc: @Sijie Guo
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2018-10-08 18:05:27 UTC - Alex Mault: Has anyone been running Pulsar on Kubernetes in production? I have been putting it through it’s paces on kube for the last month with few issues but still a bit weary to move to production. I’m hoping someone has reassurance or “here be dragons”?
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2018-10-08 18:09:31 UTC - Ali Ahmed: There are organizations testing pulsar for production K8, and some PR’s are on the way to fix some issues.
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2018-10-09 01:55:44 UTC - hj: @Sanjeev Kulkarni These two examples are  calculating for all, and I want to calculate each device individually. Is Pulsar function support the GroupBy ？
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2018-10-09 02:41:52 UTC - Sanjeev Kulkarni: @hj could you pl describe your usecase a little bit more?
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2018-10-09 03:17:34 UTC - hj: A collect server collect data from devices and send them to Pulsar topic . and I want use windowing function to calculate each device avg temperature。
`
example:
input:
{"deviceNo": 'L-12', "value": 12, "time":.....}
{"deviceNo": 'L-12', "value": 12, "time":.....}
{"deviceNo": 'L-12', "value": 12, "time":.....}
{"deviceNo": 'L-13', "value": 12, "time":.....}
{"deviceNo": 'L-13', "value": 12, "time":.....}
......

one minute.......

output:
L-12: 12
L-13: 12
`
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2018-10-09 04:09:14 UTC - Sanjeev Kulkarni: Thanks @hj. Currently pulsar functions does not support a join type operation. Currently it can be accomplished using the windowing function as described above and doing a avg calc per device in each window
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2018-10-09 06:55:23 UTC - Samuel Sun: Hi , for the smallest deployment of pulsar, can I put zk and bookkeepr in the same server, and pulsar another one ?
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2018-10-09 06:56:34 UTC - Ali Ahmed: you can run everything in one server with the standalone mode
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2018-10-09 06:56:57 UTC - Samuel Sun: thanks, if want to try cluster mode .
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2018-10-09 06:57:23 UTC - Samuel Sun: is pulsar a stateless service ?
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2018-10-09 06:57:31 UTC - Samuel Sun: pulsar broker
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2018-10-09 06:59:22 UTC - Ali Ahmed: yes
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2018-10-09 07:02:35 UTC - Samuel Sun: thanks
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2018-10-09 07:35:57 UTC - Sijie Guo: @Alex Mault yes. sticorp is running pulsar on kubernetes on gcp. the helm script that in pulsar repo was contributed by the engineers from sticorp.

<https://streaml.io/blog/building-data-driven-applications-with-apache-pulsar-at-sticorp>
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2018-10-09 07:36:30 UTC - Sijie Guo: @Jean-Bernard van Zuylen +1 for this proposal.
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2018-10-09 07:37:40 UTC - Sijie Guo: @Shalin what is your memory settings? I guess that’s related to netty bytebuf allocator settings.

let me know your jvm settings and your traffic pattern, I can suggest how to adjust netty bytebuf allocator settings
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2018-10-09 08:17:26 UTC - Jean-Bernard van Zuylen: @Sijie Guo Cool! Any preference to an option in `ClientBuilder` or default from Java?
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2018-10-09 08:18:25 UTC - Sijie Guo: no preference, workerThreadAsDaemon looks good to me
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2018-10-09 08:19:08 UTC - Jean-Bernard van Zuylen: @Matteo Merli Are you ok with this?
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