Shaoxuan Wang created FLINK-6047:
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Summary: Master Jira for "Retraction for Flink Streaming"
Key: FLINK-6047
URL: https://issues.apache.org/jira/browse/FLINK-6047
Project: Flink
Issue Type: New Feature
Reporter: Shaoxuan Wang
Assignee: Shaoxuan Wang
[Design doc]:
https://docs.google.com/document/d/18XlGPcfsGbnPSApRipJDLPg5IFNGTQjnz7emkVpZlkw
[Introduction]:
"Retraction" is an important building block for data streaming to refine the
early fired results in streaming. “Early firing” are very common and widely
used in many streaming scenarios, for instance “window-less” or unbounded
aggregate and stream-stream inner join, windowed (with early firing) aggregate
and stream-stream inner join. There are mainly two cases that require
retractions: 1) update on the keyed table (the key is either a primaryKey (PK)
on source table, or a groupKey/partitionKey in an aggregate); 2) When dynamic
windows (e.g., session window) are in use, the new value may be replacing more
than one previous window due to window merging.
To the best of our knowledge, the retraction for the early fired streaming
results has never been practically solved before. In this proposal, we develop
a retraction solution and explain how it works for the problem of “update on
the keyed table”. The same solution can be easily extended for the dynamic
windows merging, as the key component of retraction - how to refine an early
fired results - is the same across different problems.
[Proposed Jiras]:
Implement decoration phase for predicated logical plan rewriting after volcano
optimization phase
Add source with table primary key and replace table property
Add sink tableInsert and NeedRetract property
Implement the retraction for partitioned unbounded over window aggregate
Implement the retraction for stream-stream inner join
Implement the retraction for the early firing window
Implement the retraction for the dynamic window with early firing
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