[FLINK-15658][table-planner-blink] Fix duplicate field names exception when join on the same key multiple times

[wuchong]

What is the purpose of the change

The exmaple raised in the JIRA that batch can run successfully, but streaming will fail. The root cause is that the join key may be duplicate and the constructed key RowType will have duplicate field names.

Brief change log

We do not provide field names for the result key type, because we may have duplicate key fields and the field names may conflict.

Verifying this change

Added an IT case to verify this, the IT case will fail without this fix.

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

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / 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 e0a7512 (Tue Feb 04 06:38:44 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

[JingsongLi]

Thanks @wuchong , I've always felt that the methods of the ProjectionCodeGenerator is a little redundant.
What about add method to ProjectionCodeGenerator:

  def generateProjection(
      name: String,
      inputType: RowType,
      inputMapping: Array[Int]): GeneratedProjection = {
    val ctx = CodeGeneratorContext.apply(new TableConfig)
    val outputType = RowType.of(inputMapping.map(inputType.getChildren.get):_ *)
    generateProjection(ctx, name, inputType, outputType, inputMapping)
  }

[JingsongLi]

rowType.toRowType()

[flinkbot]

CI report:

• e0a7512 Travis: CANCELED Azure: SUCCESS
• 38e5a57 Travis: SUCCESS Azure: PENDING

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 @wuchong , I've always felt that the methods of the ProjectionCodeGenerator is a little redundant.
What about add method to ProjectionCodeGenerator:

  def generateProjection(
      name: String,
      inputType: RowType,
      inputMapping: Array[Int]): GeneratedProjection = {
    val ctx = CodeGeneratorContext.apply(new TableConfig)
    val outputType = RowType.of(inputMapping.map(inputType.getChildren.get):_ *)
    generateProjection(ctx, name, inputType, outputType, inputMapping)
  }

However, the outputType is still required to build the key BaseRowTypeInfo, so the new method doesn't help much here.

[JingsongLi]

Looks good to me.

[wuchong]

Thanks for the reveiwing @JingsongLi .

Merging...