Re:Re:Re:在自定义表聚合函数 TableAggregateFunction 使用 emitUpdateWithRetract 异常

Mon, 23 May 2022 03:24:28 -0700 

Flink 版本：1.13.5




函数完整代码如下：
```
public class Top2RetractTableAggregateFunction extends 
TableAggregateFunction<Tuple2<Long, Integer>, 
Top2RetractTableAggregateFunction.Top2RetractAccumulator> {
    private static final Logger LOG = 
LoggerFactory.getLogger(Top2RetractTableAggregateFunction.class);
    // Top2 聚合中间结果数据结构
    public static class Top2RetractAccumulator {
        public long beforeFirst = 0;
        public long beforeSecond = 0;
        public long afterFirst = 0;
        public long afterSecond = 0;
    }


    // 创建 Top2Accumulator 累加器并做初始化
    @Override
    public Top2RetractAccumulator createAccumulator() {
        LOG.info("[INFO] createAccumulator ...........................");
        Top2RetractAccumulator acc = new Top2RetractAccumulator();
        acc.beforeFirst = Integer.MIN_VALUE;
        acc.beforeSecond = Integer.MIN_VALUE;
        acc.afterFirst = Integer.MIN_VALUE;
        acc.afterSecond = Integer.MIN_VALUE;
        return acc;
    }


    // 接收输入元素并累加到 Accumulator 数据结构
    public void accumulate(Top2RetractAccumulator acc, Long value) {
        LOG.info("[INFO] accumulate ...........................");
        if (value > acc.afterFirst) {
            acc.afterSecond = acc.afterFirst;
            acc.afterFirst = value;
        } else if (value > acc.afterSecond) {
            acc.afterSecond = value;
        }
    }


    // 带撤回的输出
    public void emitUpdateWithRetract(Top2RetractAccumulator acc, 
RetractableCollector<Tuple2<Long, Integer>> out) {
        LOG.info("[INFO] emitUpdateWithRetract ...........................");
        if (!Objects.equals(acc.afterFirst, acc.beforeFirst)) {
            // 撤回旧记录
            if (acc.beforeFirst != Integer.MIN_VALUE) {
                out.retract(Tuple2.of(acc.beforeFirst, 1));
            }
            // 输出新记录
            out.collect(Tuple2.of(acc.afterFirst, 1));
            acc.beforeFirst = acc.afterFirst;
        }
        if (!Objects.equals(acc.afterSecond, acc.beforeSecond)) {
            // 撤回旧记录
            if (acc.beforeSecond != Integer.MIN_VALUE) {
                out.retract(Tuple2.of(acc.beforeSecond, 2));
            }
            // 输出新记录
            out.collect(Tuple2.of(acc.afterSecond, 2));
            acc.beforeSecond = acc.afterSecond;
        }
    }
}
```
调用完整代码如下：
```
// 执行环境
StreamExecutionEnvironment env = 
StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
EnvironmentSettings settings = EnvironmentSettings
        .newInstance()
        .useOldPlanner() // Blink Planner 异常 Old Planner 可以
        .inStreamingMode()
        .build();
StreamTableEnvironment tEnv = StreamTableEnvironment.create(env, settings);


DataStream<Row> sourceStream = env.fromElements(
        Row.of("李雷", "语文", 78),
        Row.of("韩梅梅", "语文", 50),
        Row.of("李雷", "语文", 99),
        Row.of("韩梅梅", "语文", 80),
        Row.of("李雷", "英语", 90),
        Row.of("韩梅梅", "英语", 40),
        Row.of("李雷", "英语", 98),
        Row.of("韩梅梅", "英语", 88)
);


// 注册虚拟表
tEnv.createTemporaryView("stu_score", sourceStream, $("name"), $("course"), 
$("score"));
// 注册临时i系统函数
tEnv.createTemporarySystemFunction("Top2", new 
Top2RetractTableAggregateFunction());
// 调用函数
tEnv.from("stu_score")
        .groupBy($("course"))
        .flatAggregate(call("Top2", $("score")).as("score", "rank"))
        .select($("course"), $("score"), $("rank"))
        .execute()
        .print();
```





















在 2022-05-23 18:21:42，"sjf0115" <si_ji_f...@163.com> 写道：
>函数代码如下：<br/>```<br/>public class Top2RetractTableAggregateFunction extends 
>TableAggregateFunction&lt;Tuple2&lt;Long, Integer&gt;, 
>Top2RetractTableAggregateFunction.Top2RetractAccumulator&gt; {<br/>    private 
>static final Logger LOG = 
>LoggerFactory.getLogger(Top2RetractTableAggregateFunction.class);<br/>    // 
>Top2 聚合中间结果数据结构<br/>    public static class Top2RetractAccumulator {<br/>      
>  public long beforeFirst = 0;<br/>        public long beforeSecond = 0;<br/>  
>      public long afterFirst = 0;<br/>        public long afterSecond = 
>0;<br/>    }<br/><br/>    // 创建 Top2Accumulator 累加器并做初始化<br/>    
>@Override<br/>    public Top2RetractAccumulator createAccumulator() {<br/>     
>   LOG.info("[INFO] createAccumulator ...........................");<br/>      
>  Top2RetractAccumulator acc = new Top2RetractAccumulator();<br/>        
>acc.beforeFirst = Integer.MIN_VALUE;<br/>        acc.beforeSecond = 
>Integer.MIN_VALUE;<br/>        acc.afterFirst = Integer.MIN_VALUE;<br/>        
>acc.afterSecond = Integer.MIN_VALUE;<br/>        return acc;<br/>    
>}<br/><br/>    // 接收输入元素并累加到 Accumulator 数据结构<br/>    public void 
>accumulate(Top2RetractAccumulator acc, Long value) {<br/>        
>LOG.info("[INFO] accumulate ...........................");<br/>        if 
>(value &gt; acc.afterFirst) {<br/>            acc.afterSecond = 
>acc.afterFirst;<br/>            acc.afterFirst = value;<br/>        } else if 
>(value &gt; acc.afterSecond) {<br/>            acc.afterSecond = value;<br/>   
>     }<br/>    }<br/><br/>    // 带撤回的输出<br/>    public void 
>emitUpdateWithRetract(Top2RetractAccumulator acc, 
>RetractableCollector&lt;Tuple2&lt;Long, Integer&gt;&gt; out) {<br/>        
>LOG.info("[INFO] emitUpdateWithRetract ...........................");<br/>     
>   if (!Objects.equals(acc.afterFirst, acc.beforeFirst)) {<br/>            // 
>撤回旧记录<br/>            if (acc.beforeFirst != Integer.MIN_VALUE) {<br/>         
>       out.retract(Tuple2.of(acc.beforeFirst, 1));<br/>            }<br/>      
>      // 输出新记录<br/>            out.collect(Tuple2.of(acc.afterFirst, 1));<br/> 
>           acc.beforeFirst = acc.afterFirst;<br/>        }<br/>        if 
>(!Objects.equals(acc.afterSecond, acc.beforeSecond)) {<br/>            // 
>撤回旧记录<br/>            if (acc.beforeSecond != Integer.MIN_VALUE) {<br/>        
>        out.retract(Tuple2.of(acc.beforeSecond, 2));<br/>            }<br/>    
>        // 输出新记录<br/>            out.collect(Tuple2.of(acc.afterSecond, 
>2));<br/>            acc.beforeSecond = acc.afterSecond;<br/>        }<br/>    
>}<br/>}<br/>```<br/>完整调用代码：<br/>```<br/>// 执行环境<br/>StreamExecutionEnvironment 
>env = 
>StreamExecutionEnvironment.getExecutionEnvironment();<br/>env.setParallelism(1);<br/>EnvironmentSettings
> settings = EnvironmentSettings<br/>        .newInstance()<br/>        
>.useOldPlanner() // Blink Planner 异常 Old Planner 可以<br/>        
>.inStreamingMode()<br/>        .build();<br/>StreamTableEnvironment tEnv = 
>StreamTableEnvironment.create(env, settings);<br/><br/>DataStream&lt;Row&gt; 
>sourceStream = env.fromElements(<br/>        Row.of("李雷", "语文", 78),<br/>      
>  Row.of("韩梅梅", "语文", 50),<br/>        Row.of("李雷", "语文", 99),<br/>        
>Row.of("韩梅梅", "语文", 80),<br/>        Row.of("李雷", "英语", 90),<br/>        
>Row.of("韩梅梅", "英语", 40),<br/>        Row.of("李雷", "英语", 98),<br/>        
>Row.of("韩梅梅", "英语", 88)<br/>);<br/><br/>// 
>注册虚拟表<br/>tEnv.createTemporaryView("stu_score", sourceStream, $("name"), 
>$("course"), $("score"));<br/>// 
>注册临时i系统函数<br/>tEnv.createTemporarySystemFunction("Top2", new 
>Top2RetractTableAggregateFunction());<br/>// 
>调用函数<br/>tEnv.from("stu_score")<br/>        .groupBy($("course"))<br/>        
>.flatAggregate(call("Top2", $("score")).as("score", "rank"))<br/>        
>.select($("course"), $("score"), $("rank"))<br/>        .execute()<br/>        
>.print();<br/>```<br/>Flink 版本：1.13.5
>在 2022-05-23 09:55:40，"Xuyang" <xyzhong...@163.com> 写道：
>>Hi， 可以将你的taf具体代码发出来吗？还有你的版本，也贴一下。
>>
>>
>>
>>
>>--
>>
>>    Best！
>>    Xuyang
>>
>>
>>
>>
>>
>>在 2022-05-22 22:35:46，"赢峰" <si_ji_f...@163.com> 写道：
>>>
>>>
>>>在自定义表聚合函数 TableAggregateFunction 时使用的是 emitUpdateWithRetract 
>>>输出数据。在调用的时候参考文档的使用方式：
>>>```
>>>tEnv.from("stu_score")
>>>    .groupBy($("course"))
>>>    .flatAggregate(call(Top2RetractTableAggregateFunction.class, $("score")))
>>>    .select($("course"), $("f0"), $("f1"))
>>>```
>>>使用默认 blink Planner，会抛出如下异常：
>>>```
>>>Exception in thread "main" org.apache.flink.table.api.ValidationException: 
>>>Could not find an implementation method 'emitValue' in class 
>>>'com.flink.example.table.function.custom.Top2RetractTableAggregateFunction' 
>>>for function 'Top2' that matches the following signature:
>>>void 
>>>emitValue(com.flink.example.table.function.custom.Top2RetractTableAggregateFunction.Top2RetractAccumulator,
>>> org.apache.flink.util.Collector)
>>>```
>>>但是使用 Old Planner，则会正常输出：
>>>```
>>>StreamExecutionEnvironment env = 
>>>StreamExecutionEnvironment.getExecutionEnvironment();
>>>env.setParallelism(1);
>>>EnvironmentSettings settings = EnvironmentSettings
>>>        .newInstance()
>>>        .useOldPlanner()
>>>        .inStreamingMode()
>>>        .build();
>>>StreamTableEnvironment tEnv = StreamTableEnvironment.create(env, settings);
>>>```
>>>这是什么地方使用有问题？
>>>
>>>
>>>
>>>
>>>

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