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https://issues.apache.org/jira/browse/FLINK-13197?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16988604#comment-16988604
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Rui Li commented on FLINK-13197:
--------------------------------
I hit some issue when trying to query views created in Hive. The view is
created as:
{code}
create table src (key int, val string);
create view v as select key, count(*) from src group by key having count(*) > 1;
{code}
When querying this view from Flink, I hit the following exception:
{noformat}
org.apache.flink.table.api.TableException: Could not expand view. Types
mismatch.
Expected row type: RecordType(INTEGER key, BIGINT _c1)
Expanded view type: RecordType(INTEGER key, BIGINT EXPR$1)
at
org.apache.flink.table.planner.calcite.FlinkPlannerImpl.expandView(FlinkPlannerImpl.scala:191)
at
org.apache.flink.table.planner.catalog.SqlCatalogViewTable.convertToRel(SqlCatalogViewTable.java:56)
at
org.apache.flink.table.planner.plan.schema.ExpandingPreparingTable.expand(ExpandingPreparingTable.java:59)
at
org.apache.flink.table.planner.plan.schema.ExpandingPreparingTable.toRel(ExpandingPreparingTable.java:55)
{noformat}
The expected row type is what we get from {{HiveCatalog}}, and the expanded
view type is what we get after compiling the expanded query of the view.
I wonder whether it's necessary to check the equality of these two, given that
we can't anticipate what we'll get from the catalog. I think we can at least be
more lenient here, e.g. it doesn't make sense to compare the column names,
perhaps nullability either.
[~dwysakowicz] could you please share your thoughts? BTW I'm using the blink
planner.
> support querying Hive's view in Flink
> -------------------------------------
>
> Key: FLINK-13197
> URL: https://issues.apache.org/jira/browse/FLINK-13197
> Project: Flink
> Issue Type: Improvement
> 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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