In general there is no ordering guarantee between topics. So it might
depend a lot ofnthe details of your use case.
For example, if you know that it will be always two event, you could
buffer the first one in a state-store, and wait for the second one to
arrive and decide in which order to forward both events downstream for
actual processing.
HTH, Matthias
On 3/20/23 11:57 PM, Pushkar Deole wrote:
Hi All,
We have a kafka streams application that consumes from 2 different topics
say topic A and topic B. The application uses data of telephone call on
those topics and each call has a call id which is used as key to send
events to those 2 topics. e.g. for a telephone call, the 1st event related
to that call is sent to A with call id however subsequent event for that
same call might go to topic B again with call id as key.
*At times, we need to process those 2 events in an order, which is not
possible with the current topology that we are using*. *Can someone suggest
if this is possible to achieve with streams?*
The topology is as below:
Topic A has 6 partitions
Topics B has 6 partitions
Call id used as key on both topics
Kafka streams application has 3 instances that consumes from both of the
topics as source topics.
Each streams application instance has 2 stream threads thus total 6 stream
threads across 3 instances of streams application cater to 6 partitions of
inputs topics.
