flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/logical/FlinkLogicalNativeTableScan.scala

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 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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 *     http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.flink.table.plan.nodes.logical

import org.apache.flink.table.plan.metadata.FlinkRelMetadataQuery
import org.apache.flink.table.plan.nodes.FlinkConventions
import org.apache.flink.table.plan.schema.DataStreamTable

import com.google.common.collect.ImmutableList
import org.apache.calcite.plan._
import org.apache.calcite.rel.convert.ConverterRule
import org.apache.calcite.rel.core.TableScan
import org.apache.calcite.rel.logical.LogicalTableScan
import org.apache.calcite.rel.metadata.RelMetadataQuery
import org.apache.calcite.rel.{RelCollation, RelCollationTraitDef, RelNode}
import org.apache.calcite.schema.Table

import java.util
import java.util.function.Supplier

class FlinkLogicalNativeTableScan (
    cluster: RelOptCluster,
    traitSet: RelTraitSet,
    table: RelOptTable)
  extends TableScan(cluster, traitSet, table)
  with FlinkLogicalRel {

  override def copy(traitSet: RelTraitSet, inputs: util.List[RelNode]): RelNode = {
    new FlinkLogicalNativeTableScan(cluster, traitSet, getTable)
  }

  override def computeSelfCost(planner: RelOptPlanner, mq: RelMetadataQuery): RelOptCost = {
    val rowCnt = mq.getRowCount(this)
    val rowSize = mq.getAverageRowSize(this)
    planner.getCostFactory.makeCost(rowCnt, rowCnt, rowCnt * rowSize)
  }

  override def isDeterministic: Boolean = true
}

class FlinkLogicalNativeTableScanConverter
  extends ConverterRule(
    classOf[LogicalTableScan],
    Convention.NONE,
    FlinkConventions.LOGICAL,
    "FlinkLogicalNativeTableScanConverter") {

  override def matches(call: RelOptRuleCall): Boolean = {
    val scan = call.rel[TableScan](0)
    FlinkLogicalNativeTableScan.isLogicalNativeTableScan(scan)
  }

  def convert(rel: RelNode): RelNode = {
    val scan = rel.asInstanceOf[TableScan]
    FlinkLogicalNativeTableScan.create(rel.getCluster, scan.getTable)
  }
}

object FlinkLogicalNativeTableScan {
  val CONVERTER = new FlinkLogicalNativeTableScanConverter

  def isLogicalNativeTableScan(scan: TableScan): Boolean = {
    val dataStreamTable = scan.getTable.unwrap(classOf[DataStreamTable[_]])
    dataStreamTable != null
  }

  def create(cluster: RelOptCluster, relOptTable: RelOptTable): FlinkLogicalNativeTableScan = {
    val table = relOptTable.unwrap(classOf[Table])
    val traitSet = cluster.traitSetOf(Convention.NONE).replaceIfs(
      RelCollationTraitDef.INSTANCE, new Supplier[util.List[RelCollation]]() {
        def get: util.List[RelCollation] = {
          if (table != null) {
            table.getStatistic.getCollations
          } else {
            ImmutableList.of[RelCollation]
          }
        }
      })
    // FIXME: FlinkRelMdDistribution requires the current RelNode to compute
    // the distribution trait, so we have to create FlinkLogicalNativeTableScan to
    // calculate the distribution trait
    val scan = new FlinkLogicalNativeTableScan(cluster, traitSet, relOptTable)
    val newTraitSet = FlinkRelMetadataQuery.traitSet(scan)
      .replace(FlinkConventions.LOGICAL).simplify()
    scan.copy(newTraitSet, scan.getInputs).asInstanceOf[FlinkLogicalNativeTableScan]
  }
}