Oh, it seems like apache mailing server ate the attached image as Gian
said; here is the table:
total used free shared buff/cache available
Mem: 7704 6147 122 161 1435 1123
Swap: 4095 1667 2428
Frankly, this result is not accurate; since I closed all the other
applications except the build process, it shows the memory usage of `system
processes + build process` - Jihoon is right, if the test process uses 8gb
of memory as I said first, the test can't be run on Travis. The reason
would be the other something as Jihoon said - I am working on a desktop
version of Ubuntu with the different implementation of JDK (openjdk 8) to
Travis configuration. Now I guess these differences caused some side
effects. Since this is not a problem with the code, you don't need a fix.
Thanks again for your kind guidance.
Thanks,
Dongjin
On Thu, Jul 26, 2018 at 3:24 AM Jihoon Son <jihoon...@apache.org> wrote:
> @Dongjin, thank you for looking into this. I got some follow-up questions.
>
> > Druid uses above 8gb of memory for testing.
>
> How did you get this result? Did you use some tools to get the memory usage
> of only the maven process for Druid tests? When I checked last time using
> JMC, I could see that running all unit tests of each Travis Job usually use
> up to 512 MB of memory (you can find our Travis Job configuration here:
> https://github.com/apache/incubator-druid/blob/master/.travis.yml). That's
> why I set the memory limit to 512 MB for our Travis CI. Maybe we need to
> check again and raise the memory limit to avoid frequent OOM failures in
> groupBy query tests.
>
> Also, if it does use 8 GB of memory, I suspect it's a sort of bug or
> something. I don't think even our integration tests don't use such a large
> memory which run all Druid processes, ZooKeeper, and Kafka. So, we should
> figure out which tests use such a lot of memory and fix it instead of
> fixing documents.
>
> > Fwiw I think 8GB should be enough memory with the right settings, since
> our Travis CI build environment only has about 7.5GB.
>
> @Gian, the memory of the Travis instance is shared by all processes
> including OS. AFAIK, the OS requires about 1 GB of memory. It means that
> our unit tests can't be run on Travis if it needs 8 GB of memory.
>
> Best,
> Jihoon
>
> On Wed, Jul 25, 2018 at 10:01 AM Charles Allen
> <charles.al...@snap.com.invalid> wrote:
>
> > OOME seems to be showing up in some of the Travis testing as well for
> group
> > by related stuff. Unsure what's going on there.
> >
> > On Tue, Jul 24, 2018 at 9:46 PM Dongjin Lee <dong...@apache.org> wrote:
> >
> > > After some experiments, I figured out the following:
> > >
> > > 1. Druid uses above 8gb of memory for testing. (building-druid.png)
> > > 2. With 8gb(physical)+4gb(swap) of memory, the test succeeds regardless
> > of
> > > maven version (3.3.9, 3.5.2, 3.5.4) or MAVEN_OPTS. However, with
> > > 8gb(physical)+2gb(swap) of memory[^1], some tests failed. The list of
> > > failing tests differs between maven 3.3.9 and 3.5.2.
> > >
> > > In short, retaining sufficient memory solved the problem - *It seems
> like
> > > 12gb of memory is a recommended setting for building druid.* (I guess
> > > lots of you are working with the MacBook Pro with 16gb RAM, right? In
> > that
> > > case, you must not have encountered this problem.)
> > >
> > > If you are okay, may I update the building documentation for the
> newbies
> > > like me?
> > >
> > > Thanks,
> > > Dongjin
> > >
> > > +1. While building Druid, I found another problem. But this issue
> should
> > > be discussed in another thread.
> > >
> > > [^1]: You know, the other processes also occupy the memory.
> > >
> > >
> > > On Tue, Jul 24, 2018 at 3:07 AM Jihoon Son <jihoon...@apache.org>
> wrote:
> > >
> > >> I'm also using Maven 3.5.2 and not using any special configurations
> for
> > >> Maven, but I have never seen that error too.
> > >> Most of our Travis jobs have been working with only 512 MB of direct
> > >> memory. Only the 'strict compilation' Travis job requires 3 GB of
> > memory.
> > >>
> > >> I think it's worthwhile to look into this more. Maybe we somehow use
> > more
> > >> memory when we run all tests by 'mvn install'. Maybe this relates to
> the
> > >> frequent transient failures of 'processing module test', one of our
> > Travis
> > >> jobs.
> > >>
> > >> Jihoon
> > >>
> > >> On Mon, Jul 23, 2018 at 9:32 AM Gian Merlino <g...@apache.org> wrote:
> > >>
> > >> > Interesting. Fwiw, I am using Maven 3.5.2 for building Druid and it
> > has
> > >> > been working for for me. I don't think I"m using any special Maven
> > >> > overrides (at least, I don't see anything interesting in my ~/.m2
> > >> directory
> > >> > or in my environment variables). It might have to do with how much
> > >> memory
> > >> > our machines have? I do most of my builds on a Mac with 16GB RAM.
> > Maybe
> > >> try
> > >> > checking .travis.yml in the druid repo. It sets -Xmx3000m for mvn
> > >> install
> > >> > commands, which might be needed for more low memory environments.
> > >> >
> > >> > $ mvn --version
> > >> > Apache Maven 3.5.2 (138edd61fd100ec658bfa2d307c43b76940a5d7d;
> > >> > 2017-10-18T00:58:13-07:00)
> > >> > Maven home: /usr/local/Cellar/maven/3.5.2/libexec
> > >> > Java version: 1.8.0_161, vendor: Oracle Corporation
> > >> > Java home:
> > >> > /Library/Java/JavaVirtualMachines/jdk1.8.0_161.jdk/Contents/Home/jre
> > >> > Default locale: en_US, platform encoding: UTF-8
> > >> > OS name: "mac os x", version: "10.13.5", arch: "x86_64", family:
> "mac"
> > >> >
> > >> > On Mon, Jul 23, 2018 at 6:40 AM Dongjin Lee <dong...@apache.org>
> > wrote:
> > >> >
> > >> > > Finally, it seems like I found the reason. It was a composition of
> > >> > several
> > >> > > problems:
> > >> > >
> > >> > > - Druid should not be built with maven 3.5.x. With 3.5.2, Test
> > suites
> > >> > like
> > >> > > `GroupByQueryRunnerFailureTest` fails. After I switched into 3.3.9
> > >> which
> > >> > is
> > >> > > built in the latest version of IntelliJ, those errors disappeared.
> > It
> > >> > seems
> > >> > > like maven 3.5.x is not stable yet - it applied a drastic change,
> > and
> > >> it
> > >> > is
> > >> > > also why they skipped 3.4.x.
> > >> > > - It seems like Druid requires some MaxDirectMemorySize
> > configuration
> > >> for
> > >> > > some test suites. With some JVM parameter like
> > >> > `-XX:MaxDirectMemorySize=4g`
> > >> > > some test suites were passed, but not all. I am now trying the
> other
> > >> > > options with enlarged swap space.
> > >> > >
> > >> > > Question: How much MaxDirectMemorySize configuration are you
> using?
> > >> > >
> > >> > > Best,
> > >> > > Dongjin
> > >> > >
> > >> > > On Sat, Jul 21, 2018 at 3:01 AM Jihoon Son <ghoon...@gmail.com>
> > >> wrote:
> > >> > >
> > >> > > > Hi Dongjin,
> > >> > > >
> > >> > > > that is weird. It looks like the vm crashed because of out of
> > memory
> > >> > > while
> > >> > > > testing.
> > >> > > > It might be a real issue or not.
> > >> > > > Have you set any memory configuration for your maven?
> > >> > > >
> > >> > > > Jihoon
> > >> > > >
> > >> > > > On Thu, Jul 19, 2018 at 7:09 PM Dongjin Lee <dong...@apache.org
> >
> > >> > wrote:
> > >> > > >
> > >> > > > > Hi Jihoon,
> > >> > > > >
> > >> > > > > I ran `mvn clean package` following development/build
> > >> > > > > <
> > >> > > > >
> > >> > > >
> > >> > >
> > >> >
> > >>
> >
> https://github.com/apache/incubator-druid/blob/master/docs/content/development/build.md
> > >> > > > > >
> > >> > > > > .
> > >> > > > >
> > >> > > > > Dongjin
> > >> > > > >
> > >> > > > > On Fri, Jul 20, 2018 at 12:30 AM Jihoon Son <
> > jihoon...@apache.org
> > >> >
> > >> > > > wrote:
> > >> > > > >
> > >> > > > > > Hi Dongjin,
> > >> > > > > >
> > >> > > > > > what maven command did you run?
> > >> > > > > >
> > >> > > > > > Jihoon
> > >> > > > > >
> > >> > > > > > On Wed, Jul 18, 2018 at 10:38 PM Dongjin Lee <
> > >> dong...@apache.org>
> > >> > > > wrote:
> > >> > > > > >
> > >> > > > > > > Hello. I am trying to build druid, but it fails. My
> > >> environment
> > >> > is
> > >> > > > like
> > >> > > > > > the
> > >> > > > > > > following:
> > >> > > > > > >
> > >> > > > > > > - CPU: Intel(R) Core(TM) i7-7560U CPU @ 2.40GHz
> > >> > > > > > > - RAM: 7704 MB
> > >> > > > > > > - OS: ubuntu 18.04
> > >> > > > > > > - JDK: openjdk version "1.8.0_171" (default configuration,
> > >> with
> > >> > > > > > MaxHeapSize
> > >> > > > > > > = 1928 MB)
> > >> > > > > > > - Branch: master (commit: cd8ea3d)
> > >> > > > > > >
> > >> > > > > > > The error message I got is:
> > >> > > > > > >
> > >> > > > > > > [INFO]
> > >> > > > > > > >
> > >> > > > > >
> > >> > > >
> > >> >
> > ------------------------------------------------------------------------
> > >> > > > > > > > [INFO] Reactor Summary:
> > >> > > > > > > > [INFO]
> > >> > > > > > > > [INFO] io.druid:druid
> > .....................................
> > >> > > > SUCCESS [
> > >> > > > > > > > 50.258 s]
> > >> > > > > > > > [INFO] java-util
> > ..........................................
> > >> > > SUCCESS
> > >> > > > > > > [03:57
> > >> > > > > > > > min]
> > >> > > > > > > > [INFO] druid-api
> > ..........................................
> > >> > > > SUCCESS [
> > >> > > > > > > > 22.694 s]
> > >> > > > > > > > [INFO] druid-common
> > .......................................
> > >> > > > SUCCESS [
> > >> > > > > > > > 14.083 s]
> > >> > > > > > > > [INFO] druid-hll
> > ..........................................
> > >> > > > SUCCESS [
> > >> > > > > > > > 17.126 s]
> > >> > > > > > > > [INFO] extendedset
> > ........................................
> > >> > > > SUCCESS [
> > >> > > > > > > > 10.856 s]
> > >> > > > > > > >
> > >> > > > > > > > *[INFO] druid-processing
> > ...................................
> > >> > > > FAILURE
> > >> > > > > > > > [04:36 min]*[INFO] druid-aws-common
> > >> > > > > ...................................
> > >> > > > > > > > SKIPPED
> > >> > > > > > > > [INFO] druid-server
> > .......................................
> > >> > > SKIPPED
> > >> > > > > > > > [INFO] druid-examples
> > .....................................
> > >> > > SKIPPED
> > >> > > > > > > > ...
> > >> > > > > > > > [INFO]
> > >> > > > > > > >
> > >> > > > > >
> > >> > > >
> > >> >
> > ------------------------------------------------------------------------
> > >> > > > > > > > [INFO] BUILD FAILURE
> > >> > > > > > > > [INFO]
> > >> > > > > > > >
> > >> > > > > >
> > >> > > >
> > >> >
> > ------------------------------------------------------------------------
> > >> > > > > > > > [INFO] Total time: 10:29 min
> > >> > > > > > > > [INFO] Finished at: 2018-07-19T13:23:31+09:00
> > >> > > > > > > > [INFO] Final Memory: 88M/777M
> > >> > > > > > > > [INFO]
> > >> > > > > > > >
> > >> > > > > >
> > >> > > >
> > >> >
> > ------------------------------------------------------------------------
> > >> > > > > > > >
> > >> > > > > > > > *[ERROR] Failed to execute goal
> > >> > > > > > > >
> org.apache.maven.plugins:maven-surefire-plugin:2.19.1:test
> > >> > > > > > (default-test)
> > >> > > > > > > > on project druid-processing: Execution default-test of
> > goal
> > >> > > > > > > >
> org.apache.maven.plugins:maven-surefire-plugin:2.19.1:test
> > >> > > failed:
> > >> > > > > The
> > >> > > > > > > > forked VM terminated without properly saying goodbye. VM
> > >> crash
> > >> > or
> > >> > > > > > > > System.exit called?*[ERROR] Command was /bin/sh -c cd
> > >> > > > > > > > /home/djlee/workspace/java/druid/processing &&
> > >> > > > > > > > /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java -Xmx3000m
> > >> > > > > > > -Duser.language=en
> > >> > > > > > > > -Duser.country=US -Dfile.encoding=UTF-8
> > -Duser.timezone=UTC
> > >> > > > > > > >
> > >> > >
> -Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager
> > >> > > > > > > > -Ddruid.indexing.doubleStorage=double -jar
> > >> > > > > > > >
> > >> > > > > > >
> > >> > > > > >
> > >> > > > >
> > >> > > >
> > >> > >
> > >> >
> > >>
> >
> /home/djlee/workspace/java/druid/processing/target/surefire/surefirebooter1075382243904099051.jar
> > >> > > > > > > >
> > >> > > > > > >
> > >> > > > > >
> > >> > > > >
> > >> > > >
> > >> > >
> > >> >
> > >>
> >
> /home/djlee/workspace/java/druid/processing/target/surefire/surefire5444459351134757209tmp
> > >> > > > > > > >
> > >> > > > > > >
> > >> > > > > >
> > >> > > > >
> > >> > > >
> > >> > >
> > >> >
> > >>
> >
> /home/djlee/workspace/java/druid/processing/target/surefire/surefire_5173894389718744688tmp
> > >> > > > > > >
> > >> > > > > > >
> > >> > > > > > > It seems like it fails when it runs tests on
> > >> `druid-processing`
> > >> > > > module
> > >> > > > > > but
> > >> > > > > > > I can't certain. Is there anyone who can give me some
> hints?
> > >> > Thanks
> > >> > > > in
> > >> > > > > > > advance.
> > >> > > > > > >
> > >> > > > > > > Best,
> > >> > > > > > > Dongjin
> > >> > > > > > >
> > >> > > > > > > --
> > >> > > > > > > *Dongjin Lee*
> > >> > > > > > >
> > >> > > > > > > *A hitchhiker in the mathematical world.*
> > >> > > > > > >
> > >>
> > > > > > > > > *github: <http://goog_969573159/
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__goog-5F969573159_&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=S55krYhaUwTC-7EGIgllQk3Jl9k8T3fZxfZAS_5nPA4&e=
> > >
> > >> >github.com/dongjinleekr
> > >> > > > > > > <http://github.com/dongjinleekr>linkedin:
> > >> > > > > > kr.linkedin.com/in/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__kr.linkedin.com_in_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=G-v0Qp9IHM8nieX8oUBvnQfbqWN_OC_MHzk52goEzqM&e=
> > >
> > >> > > > > > > <http://kr.linkedin.com/in/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__kr.linkedin.com_in_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=G-v0Qp9IHM8nieX8oUBvnQfbqWN_OC_MHzk52goEzqM&e=
> > >
> > >> >slideshare:
> > >> > > > > > > www.slideshare.net/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.slideshare.net_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=SKr88hVIw32a2NGp3MDw-_EUvn0nFf_yISLrwD_ySYk&e=
> > >
> > >> > > > > > > <http://www.slideshare.net/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.slideshare.net_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=SKr88hVIw32a2NGp3MDw-_EUvn0nFf_yISLrwD_ySYk&e=
> > >
> > >> >*
> > >
> > >
> > >> > > > > > >
> > >> > > > > >
> > >> > > > > > --
> > >> > > > > > *Dongjin Lee*
> > >> > > > > >
> > >> > > > > > *A hitchhiker in the mathematical world.*
> > >> > > > > >
> > >>
> > > > > > > > *github: <http://goog_969573159/
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__goog-5F969573159_&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=S55krYhaUwTC-7EGIgllQk3Jl9k8T3fZxfZAS_5nPA4&e=
> > >
> > >> >github.com/dongjinleekr
> > >> > > > > > <http://github.com/dongjinleekr>linkedin:
> > >> > > > > kr.linkedin.com/in/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__kr.linkedin.com_in_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=G-v0Qp9IHM8nieX8oUBvnQfbqWN_OC_MHzk52goEzqM&e=
> > >
> > >> > > > > > <http://kr.linkedin.com/in/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__kr.linkedin.com_in_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=G-v0Qp9IHM8nieX8oUBvnQfbqWN_OC_MHzk52goEzqM&e=
> > >
> > >> >slideshare:
> > >> > > > > www.slideshare.net/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.slideshare.net_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=SKr88hVIw32a2NGp3MDw-_EUvn0nFf_yISLrwD_ySYk&e=
> > >
> > >> > > > > > <http://www.slideshare.net/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.slideshare.net_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=SKr88hVIw32a2NGp3MDw-_EUvn0nFf_yISLrwD_ySYk&e=
> > >
> > >> >*
> > >
> > >
> > >> > > > > >
> > >> > > > >
> > >> > > >
> > >> > > > --
> > >> > > > *Dongjin Lee*
> > >> > > >
> > >> > > > *A hitchhiker in the mathematical world.*
> > >> > > >
> > >>
> > > > > > *github: <http://goog_969573159/
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__goog-5F969573159_&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=S55krYhaUwTC-7EGIgllQk3Jl9k8T3fZxfZAS_5nPA4&e=
> > >
> > >> >github.com/dongjinleekr
> > >> > > > <http://github.com/dongjinleekr>linkedin:
> > >> > > kr.linkedin.com/in/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__kr.linkedin.com_in_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=G-v0Qp9IHM8nieX8oUBvnQfbqWN_OC_MHzk52goEzqM&e=
> > >
> > >> > > > <http://kr.linkedin.com/in/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__kr.linkedin.com_in_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=G-v0Qp9IHM8nieX8oUBvnQfbqWN_OC_MHzk52goEzqM&e=
> > >
> > >> >slideshare:
> > >> > > www.slideshare.net/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.slideshare.net_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=SKr88hVIw32a2NGp3MDw-_EUvn0nFf_yISLrwD_ySYk&e=
> > >
> > >> > > > <http://www.slideshare.net/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.slideshare.net_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=SKr88hVIw32a2NGp3MDw-_EUvn0nFf_yISLrwD_ySYk&e=
> > >
> > >> >*
> > >> > > >
> > >> > >
> > >> >
> > >>
> > >> --
> > >> *Dongjin Lee*
> > >>
> > >> *A hitchhiker in the mathematical world.*
> > >>
> > >> *github:
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__goog-5F969573159_&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=S55krYhaUwTC-7EGIgllQk3Jl9k8T3fZxfZAS_5nPA4&e=
> > >github.com/dongjinleekr
> > >> <http://github.com/dongjinleekr>linkedin:
> > kr.linkedin.com/in/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__kr.linkedin.com_in_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=G-v0Qp9IHM8nieX8oUBvnQfbqWN_OC_MHzk52goEzqM&e=
> >slideshare:
> > www.slideshare.net/dongjinleekr
> > >> <
> >
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.slideshare.net_dongjinleekr&d=DwMFaQ&c=ncDTmphkJTvjIDPh0hpF_w&r=HrLGT1qWNhseJBMYABL0GFSZESht5gBoLejor3SqMSo&m=thcH_tBRIMD3fQlav3ogOGyksut5JF_p3v21U7VlKyM&s=SKr88hVIw32a2NGp3MDw-_EUvn0nFf_yISLrwD_ySYk&e=
> > >*
> > >>
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: dev-unsubscr...@druid.apache.org
> > > For additional commands, e-mail: dev-h...@druid.apache.org
> >
>
> --
> *Dongjin Lee*
>
> *A hitchhiker in the mathematical world.*
>
> *github: <http://goog_969573159/>github.com/dongjinleekr
> <http://github.com/dongjinleekr>linkedin: kr.linkedin.com/in/dongjinleekr
> <http://kr.linkedin.com/in/dongjinleekr>slideshare:
> www.slideshare.net/dongjinleekr
> <http://www.slideshare.net/dongjinleekr>*
>
