Got it.
Since I am not applying any windowing strategy to the side input, does beam
automatically pickup the windowing strategy for the side inputs from the
main input? By that I mean the scope of the side input would be a per
window one and it would be different for every window. Is that correct?
Regards,
Harsh
On Tue, May 15, 2018 at 17:54 Lukasz Cwik <lc...@google.com> wrote:
> Using deduplicate + side inputs will allow you to have a consistent view
> of the account information for the entire window which can be nice since it
> gives consistent processing semantics but using a simple in memory cache to
> reduce the amount of lookups will likely be much easier to debug and
> simpler to implement and maintain.
>
> On Tue, May 15, 2018 at 2:31 PM Harshvardhan Agrawal <
> harshvardhan.ag...@gmail.com> wrote:
>
>> Thanks Raghu!
>>
>> Lukasz,
>>
>> Do you think lookups would be a better option than side inputs in my case?
>>
>>
>> On Tue, May 15, 2018 at 16:33 Raghu Angadi <rang...@google.com> wrote:
>>
>>> It should work. I think you need apply Distinct before looking up
>>> account info :
>>> billingDataPairs.apply(Keys.create()).apply(Distinct.create()).apply("LookupAccounts",
>>> ...).
>>> Note that all of the accounts are stored in single in-memory map. It
>>> should be small enough for that.
>>>
>>> On Tue, May 15, 2018 at 1:15 PM Harshvardhan Agrawal <
>>> harshvardhan.ag...@gmail.com> wrote:
>>>
>>>> Well ideally, I actually made the example a little easy. In the actual
>>>> example I have multiple reference datasets. Say, I have a tuple of Account
>>>> and Product as the key. The reason we don’t do the lookup in the DoFn
>>>> directly is that we don’t want to lookup the data for the same account or
>>>> same product multiple times across workers in a window.
>>>>
>>>> What I was thinking was that it might be better to perform the lookup
>>>> only once for each account and product in a window and then supply them as
>>>> side inputs to the main input.
>>>>
>>>> On Tue, May 15, 2018 at 16:03 Lukasz Cwik <lc...@google.com> wrote:
>>>>
>>>>> Is there a reason you don't want to read the accounting information
>>>>> within the DoFn directly from the datastore, it seems like that would be
>>>>> your simplest approach.
>>>>>
>>>>> On Tue, May 15, 2018 at 12:43 PM Harshvardhan Agrawal <
>>>>> harshvardhan.ag...@gmail.com> wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> No we don’t receive any such information from Kafka.
>>>>>>
>>>>>> The account information in the external store does change. Every time
>>>>>> we have a change in the account information we will have to recompute all
>>>>>> the billing info. Our source systems will make sure that they publish
>>>>>> messages for those accounts again.
>>>>>>
>>>>>>
>>>>>> On Tue, May 15, 2018 at 15:11 Lukasz Cwik <lc...@google.com> wrote:
>>>>>>
>>>>>>> For each BillingModel you receive over Kafka, how "fresh" should the
>>>>>>> account information be?
>>>>>>> Does the account information in the external store change?
>>>>>>>
>>>>>>> On Tue, May 15, 2018 at 11:22 AM Harshvardhan Agrawal <
>>>>>>> harshvardhan.ag...@gmail.com> wrote:
>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> We have certain billing data that arrives to us from Kafka. The
>>>>>>>> billing data is in json and it contains an account ID. In order for us
>>>>>>>> to
>>>>>>>> generate the final report we need to use some account data associated
>>>>>>>> with
>>>>>>>> the account id and is stored in an external database.
>>>>>>>>
>>>>>>>> It is possible that we get multiple billing info messages for the
>>>>>>>> same account. We want to be able to lookup the account information for
>>>>>>>> the
>>>>>>>> messages in a window and then supply that as a side input to the next
>>>>>>>> PTransform.
>>>>>>>>
>>>>>>>> Is it possible to achieve that in Beam?
>>>>>>>>
>>>>>>>> Here is my attempt:
>>>>>>>>
>>>>>>>> PCollection<KV<Integer, BillingModel>> billingDataPairs =
>>>>>>>> p.apply("ReadBillingInfo", KafkaIO.<String, String>read()
>>>>>>>> .withBootstrapServers(KAFKA_BOOTSTRAP_SERVER)
>>>>>>>> .withTopic(KAFKA_TOPIC)
>>>>>>>> .withKeyDeserializer(StringDeserializer.class)
>>>>>>>> .withValueDeserializer(StringDeserializer.class)
>>>>>>>> )
>>>>>>>> .apply("Window",
>>>>>>>> Window.into(FixedWindows.of(Duration.standardSeconds(30))))
>>>>>>>> .apply("ProcessKafkaMessages",new KafkaProcessor());
>>>>>>>>
>>>>>>>> PCollection<KV<Integer, Iterable<BillingModel>> billingData =
>>>>>>>> billingDataPairs.apply(GroupByKey.<Integer, BillingModel>create());
>>>>>>>>
>>>>>>>> PCollectionView<Map<Integer, Account>> accountData =
>>>>>>>> billingDataPairs.apply("LookupAccounts",new
>>>>>>>> AccountLookupClient()).apply(View.asMap());
>>>>>>>>
>>>>>>>> billingDataPairs.apply(ParDo.of(new DoFn<KV<Integer,
>>>>>>>> BillingModel>>(){
>>>>>>>> @ProcessElement
>>>>>>>> public void processElement(ProcessContext ctx) {
>>>>>>>> Integer accountId = ctx.element().getKey();
>>>>>>>> Iterable<BillingModel> billingModel = ctx.element().getValue();
>>>>>>>> Account account = ctx.sideinput(accountData).get(accountId);
>>>>>>>> }
>>>>>>>> }));
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Harsh
>>>>>>>> --
>>>>>>>>
>>>>>>>> *Regards,Harshvardhan Agrawal*
>>>>>>>> *267.991.6618 | LinkedIn
>>>>>>>> <https://www.linkedin.com/in/harshvardhanagr/>*
>>>>>>>>
>>>>>>> --
>>>>>>
>>>>>> *Regards,Harshvardhan Agrawal*
>>>>>> *267.991.6618 | LinkedIn
>>>>>> <https://www.linkedin.com/in/harshvardhanagr/>*
>>>>>>
>>>>> --
>>>>
>>>> *Regards,Harshvardhan Agrawal*
>>>> *267.991.6618 | LinkedIn <https://www.linkedin.com/in/harshvardhanagr/>*
>>>>
>>> --
>>
>> *Regards,Harshvardhan Agrawal*
>> *267.991.6618 | LinkedIn <https://www.linkedin.com/in/harshvardhanagr/>*
>>
> --
*Regards,Harshvardhan Agrawal*
*267.991.6618 | LinkedIn <https://www.linkedin.com/in/harshvardhanagr/>*
