[FLINK-17767][table-planner-blink]Tumbling/Sliding window aggregate support window start offset in batch and streaming mode

[wangxlong]

What is the purpose of the change

Tumbling/Sliding window aggregate support window start offset in batch and streaming mode.

Brief change log

1. TumblingGroupWindow and SlidingGroupWindow add a option offset field.
2. Modify StreamExecGroupWindowAggregate and BatchExecGroupWindowAggregate physical node.

Verifying this change

This change added tests and can be verified as follows:

1. WindowAggregateTest#testTumbleWindowWithOffset and WindowAggregateTest#testHopWindowWithOffset
2. WindowAggregateITCase#testTumblingWindowWithOffset and testSlidingWindowWithOffset

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn/Mesos, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? (no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

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Last check on commit 85c69f8 (Fri Feb 19 07:22:19 UTC 2021)

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[libenchao]

The offset parameter type is TIME in Calcite by default. Then we cannot support offsets larger than one day? E.g., we want to have a 1 week tumble window from Monday to Sunday, then we need TUMBLE(ts, INTERVAL 7 DAY, INTERVAL 3 DAY), current implementation cannot do this.

[wangxlong]

Yes, you are right. TIME type cannot support offsets larger than one day. I think we should determine what type is reasonable to use. If INTERVAL is reasonable, we can use DATETIME_INTERVAL_INTERVA and DATETIME_INTERVAL_INTERVAL_INTERVAL

[libenchao]

Personally, I prefer INTERVAL than TIME, INTERVAL is more powerful. WDYT? @wuchong ?

[wuchong]

Hi @libenchao , I'm not sure whether we can support INTERVAL here. Because AFAIK, the type has been defined by Calcite.

[libenchao]

@wuchong We can modify the definition of TUMBLE/HOP/SESSION in FlinkSqlOperatorTable, then we have the flexibility to define the operand types. (Actually I did this in 1.9 internally already)

[wangxlong]

I use INTERVAL type in this PR https://github.com/apache/flink/compare/master...wangxlong:FLINK-17767_OFFSET_USE_INTERVAL?expand=1.

[wuchong]

Personally, I don't see a strong need for INTERVAL. I think the offset is used for time zone offset, so it shoudn't larger than day.

cc @danny0405 , do you know the reason why Calcite use TIME type for the offset argument?