Re: Use case for The Broadcast State Pattern and efficient database access

Posted by Andrey Zagrebin-2 on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Use-case-for-The-Broadcast-State-Pattern-and-efficient-database-access-tp25729p25732.html

Hi Marke,

Q1: From your description of the problem, "Broadcast State Pattern" seems to be the suitable choice.
If you want to keep the same state on all parallel instances which process stream[1] and update/store that state the same way on each instance by using each element of stream[2].

Q2: Apart of simple synchronous queries to database upon getting each element of stream[2], you might benefit from using async IO (1). E.g. you could put it before broadcasting stream[2] and broadcast database response.

Best,

Andrey

(1) https://ci.apache.org/projects/flink/flink-docs-release-1.7/dev/stream/operators/asyncio.html

On Thu, Jan 24, 2019 at 1:10 PM Marke Builder <[hidden email]> wrote:

Hi,

I have a question regarding the "Broadcast State Pattern".

My job consume two streams (kafka, rabbitmq), on one of the streams come a lot of data and continuously[1]. On the other  very few and rarely[2]. I'm using the Broadcast State pattern, because the stream[2] are updating data which are required for stream[1].

Q1: Is the Broadcast State Pattern the right way?

As I mentioned above, the stream[2] provide data and "say" read additional data from a database.

Q2: What is the best(the most efficient) way to request a database from the processElement(...) function?

Many Thanks!

Marke