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From fhueske <...@git.apache.org>
Subject [GitHub] flink pull request #3714: [FLINK-6075] - Support Limit/Top(Sort) for Stream ...
Date Wed, 19 Apr 2017 15:02:23 GMT
Github user fhueske commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3714#discussion_r112217063
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/runtime/aggregate/SortUtil.scala
---
    @@ -0,0 +1,353 @@
    +/*
    + * 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.runtime.aggregate
    +
    +import org.apache.flink.table.calcite.FlinkTypeFactory
    +import org.apache.flink.api.java.typeutils.RowTypeInfo
    +import org.apache.flink.types.Row
    +import org.apache.calcite.rel.`type`._
    +import org.apache.calcite.rel.logical.LogicalSort
    +import org.apache.flink.streaming.api.functions.ProcessFunction
    +import org.apache.flink.table.functions.AggregateFunction
    +import org.apache.calcite.sql.`type`.SqlTypeName
    +import org.apache.flink.table.api.TableException
    +import org.apache.calcite.sql.`type`.SqlTypeName
    +import org.apache.calcite.sql.`type`.SqlTypeName._
    +import org.apache.flink.table.functions.Accumulator
    +import java.util.{ List => JList, ArrayList }
    +import org.apache.flink.api.common.typeinfo.{ SqlTimeTypeInfo, TypeInformation }
    +import org.apache.flink.api.java.typeutils.RowTypeInfo
    +import java.sql.Timestamp
    +import org.apache.calcite.rel.RelFieldCollation
    +import org.apache.calcite.rel.RelFieldCollation.Direction
    +import java.util.Comparator
    +import org.apache.flink.api.common.typeutils.TypeComparator
    +import org.apache.flink.api.common.typeinfo.BasicTypeInfo._
    +import java.lang.{Byte=>JByte,Integer=>JInt,Long=>JLong,Double=>JDouble,Short=>JShort,String=>JString,Float=>JFloat}
    +import java.math.{BigDecimal=>JBigDecimal}
    +import org.apache.flink.api.common.functions.MapFunction
    +
    +/**
    + * Class represents a collection of helper methods to build the sort logic.
    + * It encapsulates as well the implementation for ordering and generic interfaces
    + */
    +
    +object SortUtil {
    +
    +  /**
    +   * Function creates [org.apache.flink.streaming.api.functions.ProcessFunction] for
sorting 
    +   * elements based on proctime and potentially other fields
    +   * @param calcSort Sort logical object
    +   * @param inputType input row type
    +   * @return org.apache.flink.streaming.api.functions.ProcessFunction
    +   */
    +  private[flink] def createProcTimeSortFunction(
    +    calcSort: LogicalSort,
    +    inputType: RelDataType): ProcessFunction[Row, Row] = {
    +
    +    val keySortFields = getSortFieldIndexList(calcSort)
    +    val keySortDirections = getSortFieldDirectionList(calcSort)
    +
    +    val inputRowType = FlinkTypeFactory.toInternalRowTypeInfo(inputType).asInstanceOf[RowTypeInfo]
    +    
    +    val orderings = createOrderingComparison(inputType, keySortFields, keySortDirections)
    +    
    +    //drop time from comparison
    +    val keyIndexesNoTime = keySortFields.slice(1, keySortFields.size)
    +    val orderingsNoTime = orderings.slice(1, keySortFields.size)
    +    
    +    val rowComparator = createRowSortComparator(keyIndexesNoTime,orderingsNoTime)
    +    
    +    new ProcTimeBoundedSortProcessFunction(
    +      inputType.getFieldCount,
    +      inputRowType,
    +      rowComparator)
    +
    +  }
    +
    +   /**
    +   * Function creates a row comparator for the sorting fields based on
    +   * [java.util.Comparator] objects derived from [org.apache.flink.api.common.TypeInfo]
    +   * @param keyIndex the indexes of the fields on which the sorting is done. 
    +   * First is expected to be the time  
    +   * @param orderings the [UntypedOrdering] objects 
    +   * @return Array of ordering objects
    +   */
    +  def createRowSortComparator(keyIndex: Array[Int],
    --- End diff --
    
    We can use the `RowComparator` and don't need to implement own comparators:
    
    ```
    def createRowComparator(
        inputRowType: RelDataType,
        fieldIdxs: Array[Int],
        fieldComps: Array[TypeComparator[AnyRef]],
        fieldOrders: Array[Boolean]): TypeComparator[Row] = {
    
      val rowComp = new RowComparator(
        inputRowType.getFieldCount,
        fieldIdxs,
        fieldComps,
        new Array[TypeSerializer[AnyRef]](0), // serializers can be empty. Are only used for
serialized comparisons
        fieldOrders)
    
      rowComp
    }
    ```


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