flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/logical/FlinkLogicalTableSourceScan.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
 * with the License.  You may obtain a copy of the License at
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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.api.TableException
import org.apache.flink.table.calcite.FlinkTypeFactory
import org.apache.flink.table.plan.metadata.FlinkRelMetadataQuery
import org.apache.flink.table.plan.nodes.FlinkConventions
import org.apache.flink.table.plan.nodes.logical.FlinkLogicalTableSourceScan.isLogicalTableSourceScan
import org.apache.flink.table.plan.schema.{FlinkRelOptTable, TableSourceTable}
import org.apache.flink.table.sources._

import com.google.common.collect.ImmutableList
import org.apache.calcite.plan._
import org.apache.calcite.rel.`type`.RelDataType
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, RelWriter}
import org.apache.calcite.schema.Table

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

class FlinkLogicalTableSourceScan(
    cluster: RelOptCluster,
    traitSet: RelTraitSet,
    relOptTable: FlinkRelOptTable)
  extends TableScan(cluster, traitSet, relOptTable)
  with FlinkLogicalRel {

  val tableSource: TableSource = relOptTable.unwrap(classOf[TableSourceTable]).tableSource

  def copy(
      traitSet: RelTraitSet,
      relOptTable: FlinkRelOptTable): FlinkLogicalTableSourceScan = {
    new FlinkLogicalTableSourceScan(cluster, traitSet, relOptTable)
  }

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

  override def deriveRowType(): RelDataType = {
    val flinkTypeFactory = cluster.getTypeFactory.asInstanceOf[FlinkTypeFactory]

    tableSource match {
      case s: StreamTableSource[_] =>
        TableSourceUtil.getRelDataType(s, None, streaming = true, flinkTypeFactory)
      case _: BatchTableSource[_] =>
        flinkTypeFactory.buildLogicalRowType(tableSource.getTableSchema, isStreaming = false)
      case _ => throw new TableException("Unknown TableSource type.")
    }
  }

  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 explainTerms(pw: RelWriter): RelWriter = {
    super.explainTerms(pw)
        .item("fields", tableSource.getTableSchema.getColumnNames.mkString(", "))
  }

  override def isDeterministic: Boolean = true
}

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

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

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

object FlinkLogicalTableSourceScan {
  val CONVERTER = new FlinkLogicalTableSourceScanConverter

  def isLogicalTableSourceScan(scan: TableScan): Boolean = {
    val tableSourceTable = scan.getTable.unwrap(classOf[TableSourceTable])
    tableSourceTable match {
      case _: TableSourceTable => true
      case _ => false
    }
  }

  def create(cluster: RelOptCluster, relOptTable: FlinkRelOptTable): FlinkLogicalTableSourceScan = {
    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 FlinkLogicalTableSourceScan to
    // calculate the distribution trait
    val scan = new FlinkLogicalTableSourceScan(cluster, traitSet, relOptTable)
    val newTraitSet = FlinkRelMetadataQuery.traitSet(scan)
      .replace(FlinkConventions.LOGICAL).simplify()
    scan.copy(newTraitSet, scan.getInputs).asInstanceOf[FlinkLogicalTableSourceScan]
  }
}