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https://issues.apache.org/jira/browse/FLINK-3849?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15929614#comment-15929614
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ASF GitHub Bot commented on FLINK-3849:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3520#discussion_r106609749
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/rules/common/PushFilterIntoTableSourceScanRuleBase.scala
---
@@ -36,36 +43,34 @@ trait PushFilterIntoTableSourceScanRuleBase {
filterableSource: FilterableTableSource[_],
description: String): Unit = {
- if (filterableSource.isFilterPushedDown) {
- // The rule can get triggered again due to the transformed "scan =>
filter"
- // sequence created by the earlier execution of this rule when we
could not
- // push all the conditions into the scan
- return
- }
+ Preconditions.checkArgument(!filterableSource.isFilterPushedDown)
val program = calc.getProgram
+ val functionCatalog = FunctionCatalog.withBuiltIns
val (predicates, unconvertedRexNodes) =
RexProgramExtractor.extractConjunctiveConditions(
program,
call.builder().getRexBuilder,
- tableSourceTable.tableEnv.getFunctionCatalog)
+ functionCatalog)
if (predicates.isEmpty) {
// no condition can be translated to expression
return
}
- val (newTableSource, remainingPredicates) =
filterableSource.applyPredicate(predicates)
- // trying to apply filter push down, set the flag to true no matter
whether
- // we actually push any filters down.
- newTableSource.setFilterPushedDown(true)
+ val remainingPredicates = new util.LinkedList[Expression]()
+ predicates.foreach(e => remainingPredicates.add(e))
+
+ val newTableSource =
filterableSource.applyPredicate(remainingPredicates)
--- End diff --
OK, you're right. Thanks for the example.
> 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.
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