[
https://issues.apache.org/jira/browse/FLINK-3754?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15253850#comment-15253850
]
ASF GitHub Bot commented on FLINK-3754:
---------------------------------------
Github user yjshen commented on the pull request:
https://github.com/apache/flink/pull/1916#issuecomment-213411425
For ease of review, I would like to explain this RP with more details.
While table api are called to construct a query, it was first constructed
as a operator tree, `LogicalNode` is used to express the tree node. Therefore,
after we finished constructing a query and about to translate it into a
dataset/datastream program, the constructed logical plan looks like:
```
Aggregate(List of group by, List of aggregate)
+- Filter (condition expression)
+- Union
+- Project (select column expression)
+- TableScan(DS1)
+- Project (select column expression)
+- TableScan(DS2)
```
At this time, only the leaf node: TableScan (`CatalogNode` in current
implementation) is equipped with type information, in order to do plan
validation, we need to **annotate** the full logical plan with type information
first and use type information to do **validate** works.
> Add a validation phase before construct RelNode using TableAPI
> --------------------------------------------------------------
>
> Key: FLINK-3754
> URL: https://issues.apache.org/jira/browse/FLINK-3754
> Project: Flink
> Issue Type: Improvement
> Components: Table API
> Affects Versions: 1.0.0
> Reporter: Yijie Shen
> Assignee: Yijie Shen
>
> Unlike sql string's execution, which have a separate validation phase before
> RelNode construction, Table API lacks the counterparts and the validation is
> scattered in many places.
> I suggest to add a single validation phase and detect problems as early as
> possible.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
