[jira] [Commented] (FLINK-7426) Table API does not support null values in keys

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-7426?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16188420#comment-16188420 ] 

ASF GitHub Bot commented on FLINK-7426:
---------------------------------------

Github user fhueske commented on a diff in the pull request:

    https://github.com/apache/flink/pull/4732#discussion_r142165496
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/runtime/CRowKeySelector.scala ---
    @@ -0,0 +1,51 @@
    +/*
    + * 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
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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.runtime
    +
    +import org.apache.flink.api.common.typeinfo.TypeInformation
    +import org.apache.flink.api.java.functions.KeySelector
    +import org.apache.flink.api.java.typeutils.ResultTypeQueryable
    +import org.apache.flink.table.runtime.types.CRow
    +import org.apache.flink.types.Row
    +
    +/**
    +  * Null-aware key selector.
    +  */
    +class CRowKeySelector(
    +    val keyFields: Array[Int],
    +    @transient var returnType: TypeInformation[Row])
    +  extends KeySelector[CRow, Row]
    +  with ResultTypeQueryable[Row] {
    +
    +  override def getKey(value: CRow): Row = {
    +    val row = value.row
    +    val fields = keyFields
    +
    +    val newKey = new Row(fields.length)
    +    var i = 0
    +    while (i < fields.length) {
    +      newKey.setField(i, row.getField(fields(i)))
    --- End diff --
    
    should we add a `project(int[])` method to `Row` similar to `Row.copy()` to reduce the number of method calls?


> Table API does not support null values in keys
> ----------------------------------------------
>
>                 Key: FLINK-7426
>                 URL: https://issues.apache.org/jira/browse/FLINK-7426
>             Project: Flink
>          Issue Type: Bug
>          Components: Table API & SQL
>    Affects Versions: 1.3.2
>            Reporter: Timo Walther
>            Assignee: Timo Walther
>
> The Table API uses {{keyBy}} internally, however, the generated {{KeySelector}} uses instances of {{Tuple}}. The {{TupleSerializer}} is not able to serialize null values. This causes issues during checkpointing or when using the RocksDB state backend. We need to replace all {{keyBy}} calls with a custom {{RowKeySelector}}.
> {code}
> class AggregateITCase extends StreamingWithStateTestBase {
>   private val queryConfig = new StreamQueryConfig()
>   queryConfig.withIdleStateRetentionTime(Time.hours(1), Time.hours(2))
>   @Test
>   def testDistinct(): Unit = {
>     val env = StreamExecutionEnvironment.getExecutionEnvironment
>     env.setStateBackend(getStateBackend)
>     val tEnv = TableEnvironment.getTableEnvironment(env)
>     StreamITCase.clear
>     val t = StreamTestData.get3TupleDataStream(env).toTable(tEnv, 'a, 'b, 'c)
>       .select('b, Null(Types.LONG)).distinct()
>     val results = t.toRetractStream[Row](queryConfig)
>     results.addSink(new StreamITCase.RetractingSink).setParallelism(1)
>     env.execute()
>     val expected = mutable.MutableList("1,null", "2,null", "3,null", "4,null", "5,null", "6,null")
>     assertEquals(expected.sorted, StreamITCase.retractedResults.sorted)
>   }
> {code}



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