[
https://issues.apache.org/jira/browse/FLINK-3848?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15725770#comment-15725770
]
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_r91056853
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/plan/rules/dataSet/BatchProjectableTableSourceScanRule.scala
---
@@ -0,0 +1,109 @@
+/*
+ * 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.dataSet
+
+
+import org.apache.calcite.plan.RelOptRule._
+import org.apache.calcite.plan.{RelOptRule, RelOptRuleCall}
+import org.apache.calcite.rel.logical.{LogicalCalc, LogicalProject,
LogicalTableScan}
+import org.apache.calcite.rex._
+import org.apache.flink.api.table.plan.rules.util.CalcConverter._
+import
org.apache.flink.api.table.plan.nodes.dataset.{BatchTableSourceScan,
DataSetCalc}
+import org.apache.flink.api.table.plan.schema.TableSourceTable
+import org.apache.flink.api.table.sources.{BatchTableSource,
ProjectableTableSource}
+
+import scala.collection.JavaConverters._
+
+/** Rule to convert a couple of [[LogicalCalc]] <- [[LogicalTableScan]]
with [[LogicalProject]]
+ * into a [[LogicalCalc]] <- [[BatchTableSourceScan]].
+ */
+class BatchProjectableTableSourceScanRule
+ extends RelOptRule(
+ operand(classOf[DataSetCalc],
+ operand(classOf[BatchTableSourceScan], none())),
+ "BatchProjectableTableSourceScanRule") {
+
+ /** Rule must only match if TableScan targets a [[BatchTableSource]],
+ * LogicalProject targets a [[ProjectableTableSource]]
+ */
+ override def matches(call: RelOptRuleCall): Boolean = {
+ val scan: BatchTableSourceScan =
call.rel(1).asInstanceOf[BatchTableSourceScan]
+ val dataSetTable = scan.getTable.unwrap(classOf[TableSourceTable])
+ dataSetTable match {
+ case tst: TableSourceTable =>
+ tst.tableSource match {
+ case s: BatchTableSource[_] =>
+ s.isInstanceOf[ProjectableTableSource[_]]
+ case _ =>
+ false
+ }
+ case _ =>
+ false
+ }
+ }
+
+ override def onMatch(call: RelOptRuleCall): Unit = {
+ val calc: DataSetCalc = call.rel(0).asInstanceOf[DataSetCalc]
+ val scan: BatchTableSourceScan =
call.rel(1).asInstanceOf[BatchTableSourceScan]
+
+ val tableSource =
scan.getTable.unwrap(classOf[TableSourceTable]).tableSource
+ val usedFields: Array[Int] = extractRefInputFields(calc)
+ if (tableSource.getNumberOfFields == usedFields.length) {
+ return
+ }
+
+ val projectableSource =
tableSource.asInstanceOf[ProjectableTableSource[_]]
+
+ val newTableSource = projectableSource.setProjection(usedFields)
+ val (newProjectExprs, newConditionExpr) = rewriteCalcExprs(calc,
usedFields)
--- End diff --
Let the `rewriteCalcExprs` generate a new `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)
