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From Jakub Stransky <stransky...@gmail.com>
Subject Re: Standalone cluster node utilization
Date Thu, 14 Jul 2016 17:22:02 GMT
HI Talebzadeh,

we are using 6 worker machines - running.

We are reading the data through sqlContext (data frame) as it is suggested
in the documentation over the JdbcRdd

prop just specifies name, password, and driver class.

Right after this data load we register it as a temp table

    val df_init = sqlContext.read
      .jdbc(
        url = Configuration.dbUrl,
        table = Configuration.dbTable,
        prop
      )

    df_init.registerTempTable("df_init")

Afterwords we do some data filtering, column selection and filtering some
rows with sqlContext.sql ("select statement here")

and after this selection we try to repartition the data in order to get
them distributed across the cluster and that seems it is not working. And
then we persist that filtered and selected dataFrame.

And the desired state should be filtered dataframe should be distributed
accross the nodes in the cluster.

Jakub



On 14 July 2016 at 19:03, Mich Talebzadeh <mich.talebzadeh@gmail.com> wrote:

> Hi Jakub,
>
> Sounds like one executor. Can you point out:
>
>
>    1. The number of slaves/workers you are running
>    2. Are you using JDBC to read data in?
>    3. Do you register DF as temp table and if so have you cached temp
>    table
>
> Sounds like only one executor is active and the rest are sitting idele.
>
> At O/S level you should see many CoarseGrainedExecutorBackend through jps
> each corresponding to one executor. Are they doing anything?
>
> HTH
>
> Dr Mich Talebzadeh
>
>
>
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> On 14 July 2016 at 17:18, Jakub Stransky <stransky.ja@gmail.com> wrote:
>
>> Hello,
>>
>> I have a spark  cluster running in a single mode, master + 6 executors.
>>
>> My application is reading a data from database via DataFrame.read then
>> there is a filtering of rows. After that I re-partition data and I wonder
>> why on the executors page of the driver UI I see RDD blocks all allocated
>> still on single executor machine
>>
>> [image: Inline images 1]
>> As highlighted on the picture above. I did expect that after re-partition
>> the data will be shuffled across cluster but that is obviously not
>> happening here.
>>
>> I can understand that database read is happening in non-parallel fashion
>> but re-partition  should fix it as far as I understand.
>>
>> Could someone experienced clarify that?
>>
>> Thanks
>>
>
>


-- 
Jakub Stransky
cz.linkedin.com/in/jakubstransky

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