org.apache.flink.table.planner.plan.nodes.common.CommonCalc.scala Maven / Gradle / Ivy

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This module bridges Table/SQL API and runtime. It contains all resources that are required during pre-flight and runtime phase. The content of this module is work-in-progress. It will replace flink-table-planner once it is stable. See FLINK-11439 and FLIP-32 for more details.

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/*
 * 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.planner.plan.nodes.common

import org.apache.flink.table.planner.plan.nodes.ExpressionFormat.ExpressionFormat
import org.apache.flink.table.planner.plan.nodes.{ExpressionFormat, FlinkRelNode}
import org.apache.flink.table.planner.plan.utils.RelExplainUtil.{conditionToString, preferExpressionFormat}

import org.apache.calcite.plan.{RelOptCluster, RelOptCost, RelOptPlanner, RelTraitSet}
import org.apache.calcite.rel.core.Calc
import org.apache.calcite.rel.hint.RelHint
import org.apache.calcite.rel.metadata.RelMetadataQuery
import org.apache.calcite.rel.{RelNode, RelWriter}
import org.apache.calcite.rex.{RexCall, RexInputRef, RexLiteral, RexProgram}

import java.util.Collections

import scala.collection.JavaConversions._

/**
  * Base class for flink [[Calc]].
  */
abstract class CommonCalc(
    cluster: RelOptCluster,
    traitSet: RelTraitSet,
    input: RelNode,
    calcProgram: RexProgram)
  extends Calc(cluster, traitSet, Collections.emptyList[RelHint](), input, calcProgram)
  with FlinkRelNode {

  override def computeSelfCost(planner: RelOptPlanner, mq: RelMetadataQuery): RelOptCost = {
    val calcProgram = getProgram
    // compute number of expressions that do not access a field or literal, i.e. computations,
    // conditions, etc. We only want to account for computations, not for simple projections.
    // CASTs in RexProgram are reduced as far as possible by ReduceExpressionsRule
    // in normalization stage. So we should ignore CASTs here in optimization stage.
    val compCnt = calcProgram.getProjectList.map(calcProgram.expandLocalRef).toList.count {
      case _: RexInputRef => false
      case _: RexLiteral => false
      case c: RexCall if c.getOperator.getName.equals("CAST") => false
      case _ => true
    }
    val newRowCnt = mq.getRowCount(this)
    // TODO use inputRowCnt to compute cpu cost
    planner.getCostFactory.makeCost(newRowCnt, newRowCnt * compCnt, 0)
  }

  override def explainTerms(pw: RelWriter): RelWriter = {
    pw.input("input", getInput)
      .item("select", projectionToString(preferExpressionFormat(pw)))
      .itemIf("where",
        conditionToString(calcProgram, getExpressionString, preferExpressionFormat(pw)),
        calcProgram.getCondition != null)
  }

  protected def projectionToString(
      expressionFormat: ExpressionFormat = ExpressionFormat.Prefix): String = {
    val projectList = calcProgram.getProjectList.toList
    val inputFieldNames = calcProgram.getInputRowType.getFieldNames.toList
    val localExprs = calcProgram.getExprList.toList
    val outputFieldNames = calcProgram.getOutputRowType.getFieldNames.toList

    projectList
      .map(getExpressionString(_, inputFieldNames, Some(localExprs), expressionFormat))
      .zip(outputFieldNames).map { case (e, o) =>
      if (e != o) {
        e + " AS " + o
      } else {
        e
      }
    }.mkString(", ")
  }

}