[FLINK-19077][table-runtime] Import process time temporal join operator.

[leonardBang]

What is the purpose of the change

• This pull request import process time temporal join operator. For temporal TableFunction join (LATERAL TemporalTableFunction(o.proctime)) and temporal table join (FOR SYSTEM_TIME AS OF), the Processing-time temporal join can reuse same operator implementation

Brief change log

• Reuse process time temporal join operator for legacy temporal join and temporal join

Verifying this change

Add ITCase TemporalJoinITCase and LegacyTemporalJoinITCase to verify this change.

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, 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)

[flinkbot]

Thanks a lot for your contribution to the Apache Flink project. I'm the @flinkbot. I help the community
to review your pull request. We will use this comment to track the progress of the review.

Automated Checks

Last check on commit 5364e72 (Tue Sep 01 15:48:18 UTC 2020)

Warnings:

• No documentation files were touched! Remember to keep the Flink docs up to date!

_{Mention the bot in a comment to re-run the automated checks.}

Review Progress

• ❓ 1. The [description] looks good.
• ❓ 2. There is [consensus] that the contribution should go into to Flink.
• ❓ 3. Needs [attention] from.
• ❓ 4. The change fits into the overall [architecture].
• ❓ 5. Overall code [quality] is good.

Please see the Pull Request Review Guide for a full explanation of the review process.

The Bot is tracking the review progress through labels. Labels are applied according to the order of the review items. For consensus, approval by a Flink committer of PMC member is required

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot approve description to approve one or more aspects (aspects: description, consensus, architecture and quality)
• @flinkbot approve all to approve all aspects
• @flinkbot approve-until architecture to approve everything until architecture
• @flinkbot attention @username1 [@username2 ..] to require somebody's attention
• @flinkbot disapprove architecture to remove an approval you gave earlier

[flinkbot]

CI report:

• 6bf5dc2 Azure: SUCCESS

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run travis re-run the last Travis build
• @flinkbot run azure re-run the last Azure build

[wuchong]

Thanks for the great work @leonardBang .

As we disccused offline, I think we should

1. reuse as much code as possible. Currently, the physical node and TemporalJoinUtil are not shared, it would be a maintain burden in the future. Would be great if we can reuse them, could you create an issue for this purpose?
2. Currently, the processing time temporal join doesn't wait for the first complete snapshot of right stream. It would be problematic when used in production.

[leonardBang]

@wuchong I address your comments, could you take a look?

[wuchong]

Thanks for the updating. I left some comments.

[leonardBang]

I have addressed your comments, appreciate if you can have a more look @wuchong

[wuchong]

I think this pull request has been in a very good shape. I only left some minor comments.

[leonardBang]

@flinkbot run azure

[leonardBang]

@flinkbot run azure

[wuchong]

Build is passed: https://dev.azure.com/apache-flink/apache-flink/_build/results?buildId=8452&view=results
Merging...