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https://issues.apache.org/jira/browse/FLINK-3849?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15878664#comment-15878664
]
ASF GitHub Bot commented on FLINK-3849:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3166#discussion_r102476247
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/calcite/RexNodeWrapper.scala
---
@@ -0,0 +1,106 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.table.calcite
+
+import org.apache.calcite.rex._
+import org.apache.calcite.sql._
+import org.apache.flink.table.api.TableException
+import org.apache.flink.table.expressions.{Expression, Literal,
ResolvedFieldReference}
+import org.apache.flink.table.validate.FunctionCatalog
+import org.apache.flink.table.calcite.RexNodeWrapper._
+
+abstract class RexNodeWrapper(rex: RexNode) {
+ def get: RexNode = rex
+ def toExpression(names: Map[RexInputRef, String]): Expression
+}
+
+case class RexLiteralWrapper(literal: RexLiteral) extends
RexNodeWrapper(literal) {
+ override def toExpression(names: Map[RexInputRef, String]): Expression =
{
+ val typeInfo = FlinkTypeFactory.toTypeInfo(literal.getType)
+ Literal(literal.getValue, typeInfo)
+ }
+}
+
+case class RexInputWrapper(input: RexInputRef) extends
RexNodeWrapper(input) {
+ override def toExpression(names: Map[RexInputRef, String]): Expression =
{
+ val typeInfo = FlinkTypeFactory.toTypeInfo(input.getType)
+ ResolvedFieldReference(names(input), typeInfo)
+ }
+}
+
+case class RexCallWrapper(
+ call: RexCall,
+ operands: Seq[RexNodeWrapper]) extends RexNodeWrapper(call) {
+
+ override def toExpression(names: Map[RexInputRef, String]): Expression =
{
+ val ops = operands.map(_.toExpression(names))
+ call.op match {
+ case function: SqlFunction =>
+ lookupFunction(replace(function.getName), ops)
+ case postfix: SqlPostfixOperator =>
+ lookupFunction(replace(postfix.getName), ops)
+ case operator@_ =>
+ val name = replace(s"${operator.kind}")
+ lookupFunction(name, ops)
+ }
+ }
+
+ def replace(str: String): String = {
+ str.replaceAll("\\s|_", "")
+ }
+}
+
+object RexNodeWrapper {
+
+ private var catalog: Option[FunctionCatalog] = None
+
+ def wrap(rex: RexNode, functionCatalog: FunctionCatalog): RexNodeWrapper
= {
+ catalog = Option(functionCatalog)
+ rex.accept(new WrapperVisitor)
+ }
+
+ private[table] def lookupFunction(name: String, operands:
Seq[Expression]): Expression = {
+ catalog.getOrElse(throw TableException("FunctionCatalog was not
defined"))
+ .lookupFunction(name, operands)
+ }
+}
+
+class WrapperVisitor extends RexVisitorImpl[RexNodeWrapper](true) {
--- End diff --
We have to make sure that we do not miss anything here.
IMO, we should try to translate as much as possible, but if something is
not possible, we should make sure that we recognize that and do not offer this
term to the `FilterableTableSource`.
> 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: Anton Solovev
>
> 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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