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From Raghavendra Pandey <raghavendra.pan...@gmail.com>
Subject Re: Streaming: updating broadcast variables
Date Fri, 03 Jul 2015 15:24:28 GMT
You cannot update the broadcasted variable.. It wont get reflected on
workers.
On Jul 3, 2015 12:18 PM, "James Cole" <james@binarism.net> wrote:

> Hi all,
>
> I'm filtering a DStream using a function. I need to be able to change this
> function while the application is running (I'm polling a service to see if
> a user has changed their filtering). The filter function is a
> transformation and runs on the workers, so that's where the updates need to
> go. I'm not sure of the best way to do this.
>
> Initially broadcasting seemed like the way to go: the filter is actually
> quite large. But I don't think I can update something I've broadcasted.
> I've tried unpersisting and re-creating the broadcast variable but it
> became obvious this wasn't updating the reference on the worker. So am I
> correct in thinking I can't use broadcasted variables for this purpose?
>
> The next option seems to be: stopping the JavaStreamingContext, creating a
> new one from the SparkContext, updating the filter function, and
> re-creating the DStreams (I'm using direct streams from Kafka).
>
> If I re-created the JavaStreamingContext would the accumulators (which are
> created from the SparkContext) keep working? (Obviously I'm going to try
> this soon)
>
> In summary:
>
> 1) Can broadcasted variables be updated?
>
> 2) Is there a better way than re-creating the JavaStreamingContext and
> DStreams?
>
> Thanks,
>
> James
>
>

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