Hi, Let me try to explain this from another user’s perspective ☺
When you run your application, Flink will map your logical/application topology onto a number of task slots (documented in more detail here: https://ci.apache.org/projects/flink/flink-docs-release-1.3/internals/job_scheduling.html). Basically, if it is possible/unless told otherwise, Flink will create a number of copies of your functions that is On 6/14/17, 21:19, "AndreaKinn" <kinn6...@hotmail.it> wrote: Hi, this is my project purpose using Kafka and Flink: <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/file/n13743/schema_png.png> In kafka topics there are streams representing sensor lectures of different subjects. Each topic is reserved for a different sensor. Every messages are attached with a key using kafka keyed messages. The key represent a subject id and the attached sensor data belong to the highlighted subject. In Flink I want to: - Get these streams - Separate streams on key (subject) basis in order to build a node chain which evaluates always same sensor values of same subjects. Thanks to you, I have correctly implemented a custom deserializer in order to get data and key from Kafka. So now I need to separate streams on key basis. As you can see in schema image, in my mind each circle represents a different physical machine in a cluster I the deserializer runs over the bigger circles which separate streams and deliver them to different smaller circles on key basis. I read the doc and I think I have to use keyBy() operator on DataStream in order to obtain a KeyedStream. It carry me to my first question: - I tried to print datastream and keyedstream. The former give me this: <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/file/n13743/nokey.png> while the latter give me this: <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/file/n13743/withkey.png> What do the numbers before the record string means (the '3' in the latter case)? Then: - How can I 'deliver' the streams in following nodes (smaller circles) on key basis? Now I'm developing on a single machine just to try and learn but also I'm a bit confused about how to develop it on cluster. -- View this message in context: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/How-to-divide-streams-on-key-basis-and-deliver-them-tp13743.html Sent from the Apache Flink User Mailing List archive. mailing list archive at Nabble.com.
