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https://issues.apache.org/jira/browse/FLINK-13197?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16994640#comment-16994640
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Jark Wu commented on FLINK-13197:
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Hi Dawid Wysakowicz Danny Chen, About add a cast:
> we may lose some plan promotion like project merge or transpose or reduction
I don't think so, is our optimizer too weak? I think redundant cast will be
removed easily by optimizer and should not affect optimizer.
And I think cast will enhance correctness, image:
- view sql will produce nullable fields
- view schema define fields not null.
- our code generator for cast consider null check, cast null to a not null
field will fail.
- So add a cast is good to verify the data.
And maybe not only field name, nullable, but also precision, this kind of scene
really needs a cast to transform.
So I am +1 for add a cast, What do you think?
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I repost [~lzljs3620320]'s comment under FLINK-15186 here, to make the
discussion in a thread.
>From my point of view, if we only need to rename fields, it would be great to
>avoid a cast project.
But if we want to handling nullable and precision, I think a project is
required and it's fine to have a project on the view.
If the cast project can'be avoided, why not simply introduce a cast project.
So I'm also +1 for cast project.
> Verify querying Hive's view in Flink
> ------------------------------------
>
> Key: FLINK-13197
> URL: https://issues.apache.org/jira/browse/FLINK-13197
> Project: Flink
> Issue Type: Test
> Components: Connectors / Hive
> Reporter: Bowen Li
> Assignee: Rui Li
> Priority: Major
> Fix For: 1.10.0
>
>
> One goal of HiveCatalog and hive integration is to enable Flink-Hive
> interoperability, that is Flink should understand existing Hive meta-objects,
> and Hive meta-objects created thru Flink should be understood by Hive.
> Taking an example of a Hive view v1 in HiveCatalog and database hc.db. Unlike
> an equivalent Flink view whose full path in expanded query should be
> hc.db.v1, the Hive view's full path in the expanded query should be db.v1
> such that Hive can understand it, no matter it's created by Hive or Flink.
> [~lirui] can you help to ensure that Flink can also query Hive's view in both
> Flink planner and Blink planner?
> cc [~xuefuz]
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