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From M Singh <mans2si...@yahoo.com>
Subject Re: Emitting current state to a sink
Date Tue, 30 Apr 2019 10:16:42 GMT
 Thanks Avi for your help.  Mans

    On Tuesday, April 30, 2019, 5:57:51 AM EDT, Avi Levi <avi.levi@bluevoyant.com> wrote:
 
 
 Sure! 
you get the context and the collector in the processBroadcastElement method see snippet below 
  override def processBroadcastElement(value: BroadcastRequest, ctx: KeyedBroadcastProcessFunction[String,
Request, BroadcastRequest, String]#Context, out: Collector[String]): Unit = {
    ....   
    ctxctx.applyToKeyedState(stateDescriptor, new KeyedStateFunction[String, ValueState[String]]
{  override def process(key: String, state: ValueState[String]): Unit = Option(state.value()).foreach(s
=> out.collect(s))
  }) ... 
 }
On Mon, Apr 29, 2019 at 5:45 PM M Singh <mans2singh@yahoo.com> wrote:

This Message originated outside your organization.
 Hi Avi:
Can you please elaborate (or include an example/code snippet) of how you were able to achieve
collecting the keyed states from the processBroadcastElement method using the applyToKeyedState
?  

I am trying to understand which collector you used to emit the state since the broadcasted
elements/state might be different from the non-broadcast elements/state.
Thanks for your help.

Mans
    On Monday, April 29, 2019, 7:29:23 AM EDT, Fabian Hueske <fhueske@gmail.com> wrote:
 
 
 Nice! 
Thanks for the confirmation :-)
Am Mo., 29. Apr. 2019 um 13:21 Uhr schrieb Avi Levi <avi.levi@bluevoyant.com>:

Thanks! Works like a charm :)

On Mon, Apr 29, 2019 at 12:11 PM Fabian Hueske <fhueske@gmail.com> wrote:

This Message originated outside your organization.
Hi Avi,
I'm not sure if  you cannot emit data from the keyed state when you receive a broadcasted
message.
The Context parameter of the processBroadcastElement() method in the KeyedBroadcastProcessFunction
has the applyToKeyedState() method.The method takes a KeyedStateFunction that is applied to
each key of a state, but does not provide a Collector to emit data.Maybe you can pass the
collector to the KeyedStateFunction and emit records while it iterates over the key space.

Best, Fabian

Am Fr., 26. Apr. 2019 um 17:35 Uhr schrieb Avi Levi <avi.levi@bluevoyant.com>:

Hi Timo,I defiantly did. but broadcasting a command and trying to address the persisted state
(I mean the state of the data stream and not the broadcasted one) you get the exception that
I wrote (java.lang.NullPointerException: No key set. This method should not be called outside
of a keyed context). e.g doing something likeoverride def processBroadcastElement(value: BroadcastRequest,
ctx: KeyedBroadcastProcessFunction[String, Request, BroadcastRequest, Response]#Context, out:
Collector[Response]): Unit = {
  value match {
    case Command(StateCmd.Fetch, _) =>
      if (state.value() != null) {
        ouout.collecy(state.value())
      }will yield that exception
BRAvi
On Fri, Apr 26, 2019 at 11:55 AM Timo Walther <twalthr@apache.org> wrote:

This Message originated outside your organization.

Hi Avi,

did you have a look at the .connect() and .broadcast() API 
functionalities? They allow you to broadcast a control stream to all 
operators. Maybe this example [1] or other examples in this repository 
can help you.

Regards,
Timo

[1] 
https://github.com/ververica/flink-training-exercises/blob/master/src/main/java/com/dataartisans/flinktraining/solutions/datastream_java/broadcast/TaxiQuerySolution.java

Am 26.04.19 um 07:57 schrieb Avi Levi:
> Hi,
> We have a keyed pipeline with persisted state.
> Is there a way to broadcast a command and collect all values that 
> persisted in  the state ?
>
> The end result can be for example sending a fetch command to all 
> operators and emitting the results to some sink
>
> why do we need it ? from time to time we might want to check if we are 
> missing keys what are the additional keys or simply emit the current 
> state to a table and to query it.
>
> I tried simply broadcasting a command and addressing the persisted 
> state but that resulted with:
> java.lang.NullPointerException: No key set. This method should not be 
> called outside of a keyed context.
>
> is there a good way to achieve that ?
>
> Cheers
> Avi





  
  
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