[
https://issues.apache.org/jira/browse/FLINK-3848?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15725772#comment-15725772
]
ASF GitHub Bot commented on FLINK-3848:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/2810#discussion_r91058536
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/plan/rules/util/CalcConverter.scala
---
@@ -0,0 +1,111 @@
+/*
+ * 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.api.table.plan.rules.util
+
+import org.apache.calcite.rex.{RexCall, RexInputRef, RexLocalRef, RexNode,
RexShuttle, RexSlot, RexVisitorImpl}
+import org.apache.flink.api.table.plan.nodes.dataset.DataSetCalc
+
+import scala.collection.JavaConversions._
+import scala.collection.mutable
+
+object CalcConverter {
+
+ /**
+ * extract used input fields index of DataSetCalc RelNode
+ *
+ * @param calc the DataSetCalc which to analyze
+ * @return used input fields indices
+ */
+ def extractRefInputFields(calc: DataSetCalc): Array[Int] = {
+ val visitor = new RefFieldsVisitor
+ val calcProgram = calc.calcProgram
+ // extract input fields from project expressions
+ calcProgram.getProjectList.foreach(exp =>
calcProgram.expandLocalRef(exp).accept(visitor))
+ val condition = calcProgram.getCondition
+ // extract input fields from condition expression
+ if (condition != null) {
+ calcProgram.expandLocalRef(condition).accept(visitor)
+ }
+ visitor.getFields
+ }
+
+ /**
+ * rewrite DataSetCal project expressions and condition expression
based on new input fields
+ *
+ * @param calc the DataSetCalc which to rewrite
+ * @param usedInputFields input fields index of DataSetCalc RelNode
+ * @return a tuple which contain 2 elements, the first one is rewritten
project expressions;
+ * the second one is rewritten condition expression,
+ * Note: if origin condition expression is null, the second
value is None
+ */
+ def rewriteCalcExprs(
+ calc: DataSetCalc,
+ usedInputFields: Array[Int]): (List[RexNode], Option[RexNode]) = {
--- End diff --
How about directly generating an adapted `RexProgram`?
> Add ProjectableTableSource interface and translation rule
> ---------------------------------------------------------
>
> Key: FLINK-3848
> URL: https://issues.apache.org/jira/browse/FLINK-3848
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: Fabian Hueske
> Assignee: Anton Solovev
>
> Add a {{ProjectableTableSource}} interface for {{TableSource}} implementation
> that support projection push-down.
> The interface could look as follows
> {code}
> def trait ProjectableTableSource {
> def setProjection(fields: Array[String]): Unit
> }
> {code}
> In addition we need Calcite rules to push a projection into a TableScan that
> refers to a {{ProjectableTableSource}}. We might need to tweak the cost model
> as well to push the optimizer in the right direction.
> Moreover, the {{CsvTableSource}} could be extended to implement
> {{ProjectableTableSource}}.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
