[
https://issues.apache.org/jira/browse/FLINK-3849?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15927277#comment-15927277
]
ASF GitHub Bot commented on FLINK-3849:
---------------------------------------
Github user KurtYoung commented on a diff in the pull request:
https://github.com/apache/flink/pull/3520#discussion_r106321885
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/sources/ProjectableTableSource.scala
---
@@ -24,7 +24,7 @@ package org.apache.flink.table.sources
*
* @tparam T The return type of the [[ProjectableTableSource]].
*/
-trait ProjectableTableSource[T] {
+trait ProjectableTableSource[T] extends TableSource[T] {
--- End diff --
It's because i want to unify the PushProjectIntoScan rule codes for both
batch and stream mode. And once we push down project into table source, we not
only should create a new TableScan instance, but also a new TableSource
instance. The codes are like:
```
val newTableSource = originTableSource.projectFields(usedFields)
// create a new scan with the new TableSource instance
val newScan = scan.copy(scan.getTraitSet, newTableSource)
```
At first the `projectFields` method returned `ProjectableTableSource` which
is not a `TableSource`, so i let `ProjectableTableSource` inherit from
`TableSource`. But i just noticed we can just let `projectFields` return one
`TableSource`, and problem resolved.
Will change this.
> Add FilterableTableSource interface and translation rule
> --------------------------------------------------------
>
> Key: FLINK-3849
> URL: https://issues.apache.org/jira/browse/FLINK-3849
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: Fabian Hueske
> Assignee: Kurt Young
>
> Add a {{FilterableTableSource}} interface for {{TableSource}} implementations
> which support filter push-down.
> The interface could look as follows
> {code}
> def trait FilterableTableSource {
> // returns unsupported predicate expression
> def setPredicate(predicate: Expression): Expression
> }
> {code}
> In addition we need Calcite rules to push a predicate (or parts of it) into a
> TableScan that refers to a {{FilterableTableSource}}. We might need to tweak
> the cost model as well to push the optimizer in the right direction.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
