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Question about Flink optimizer on Stream API


Hi,

I was reading some FLIP documents related to the new design of the Flink
Schedule [1] and unification of batch and stream [2]. Then I created two
different programs to learn how Flink optimizes the Query Plan in Batch and
in Stream mode (and how much further it goes). One using batch [3] and one
using Stream [4]. During the code debugging and also as it is depicted on
the document [2], the batch program uses the
org.apache.flink.optimizer.Optimizer class which generates a
"org.apache.flink.optimizer.plan.OptimizedPlan" while stream program uses
the "org.apache.flink.streaming.api.graph.StreamGraph" and every
transformation inside the packet
"org.apache.flink.streaming.api.transformations".

When I am showing the execution plan with "env.getExecutionPlan()" I see
exactly I have written on the Flink program (which it is expected).
However, I was looking for where I can see the optimized plan. I mean
decisions of operators reordering based on cost or statistics. For batch I
could find the "org.apache.flink.optimizer.costs.CostEstimator" and
"org.apache.flink.optimizer.DataStatistics". But for Stream I only found
the creation of the plan. How can I debug that? Or have a better
understanding of what Flink is doing. Do you advise me to read some other
reference about this?

Kind Regards,
Felipe

[1] Group-aware scheduling for Flink -
https://docs.google.com/document/d/1q7NOqt05HIN-PlKEEPB36JiuU1Iu9fnxxVGJzylhsxU/edit#heading=h.k15nfgsa5bnk
[2] Unified Core API for Streaming and Batch -
https://docs.google.com/document/d/1G0NUIaaNJvT6CMrNCP6dRXGv88xNhDQqZFrQEuJ0rVU/edit#
[3]
https://github.com/felipegutierrez/explore-flink/blob/master/src/main/java/org/sense/flink/examples/batch/MatrixMultiplication.java
[4]
https://github.com/felipegutierrez/explore-flink/blob/master/src/main/java/org/sense/flink/examples/stream/SensorsReadingMqttJoinQEP.java

*--*
*-- Felipe Gutierrez*

*-- skype: felipe.o.gutierrez*
*--* *https://felipeogutierrez.blogspot.com
<https://felipeogutierrez.blogspot.com>*