flink算子类在多个subtask中是各自初始化1个实例对象吗？

Sun, 15 Nov 2020 21:56:02 -0800 

Hi，all：
flink算子在多个并行度的job中，每个算子（假如1个算子都有一个对应的java类）在多个subtask中会共享1个java类实例吗？还是每个subtask都会各自的实例？
我做了一个简单测试，写了一个flatmap类，在构造方法和open方法中打印类的toString方法，发现输出都不同，是否可以证明每个subtask都初始化了自己的类实例？
希望有朋友能解释下算子在job运行中初始化的过程。

测试相关代码如下：
// flink 1.10.2版本，并行度为3
@Slf4j
public class PersonFlatMap extends RichFlatMapFunction<Tuple2<String, String>, 
Person> {
    private transient ValueState<Integer> state;

    public PersonFlatMap(){
        log.info(String.format("PersonFlatMap【%s】: 创建实例",this.toString()));
    }

    @Override
    public void open(Configuration parameters) throws IOException {
        //略去无关代码...
        log.info(String.format("PersonFlatMap【%s】:初始化状态!", this.toString()));
    }

    @Override
    public void flatMap(Tuple2<String, String> t, Collector<Person> collector) 
throws Exception {
        Person p = JSONUtil.toObject(t.f1,Person.class);
        collector.collect(p);
        if(state.value() == null){state.update(0);}
        state.update(state.value() + 1);
        log.info("state: "+state.value());
    }
}

//测试日志输出
...
flink-10.2 - [2020-11-16 13:41:54.360] - INFO  [main] 
com.toonyoo.operator.PersonFlatMap  - 
PersonFlatMap【com.toonyoo.operator.PersonFlatMap@ba8d91c】: 创建实例
//此处略去无关日志...
flink-10.2 - [2020-11-16 13:42:00.326] - INFO  [Flat Map -> Sink: Print to Std. 
Out (1/3)] org.apache.flink.runtime.state.heap.HeapKeyedStateBackend  - 
Initializing heap keyed state backend with stream factory.
flink-10.2 - [2020-11-16 13:42:00.351] - INFO  [Flat Map -> Sink: Print to Std. 
Out (1/3)] com.toonyoo.operator.PersonFlatMap  - 
PersonFlatMap【com.toonyoo.operator.PersonFlatMap@5c9d895d】:初始化状态!
flink-10.2 - [2020-11-16 13:42:00.354] - INFO  [Flat Map -> Sink: Print to Std. 
Out (3/3)] com.toonyoo.operator.PersonFlatMap  - 
PersonFlatMap【com.toonyoo.operator.PersonFlatMap@5c489c40】:初始化状态!
flink-10.2 - [2020-11-16 13:42:00.356] - INFO  [Flat Map -> Sink: Print to Std. 
Out (2/3)] com.toonyoo.operator.PersonFlatMap  - 
PersonFlatMap【com.toonyoo.operator.PersonFlatMap@1cd4f5c9】:初始化状态!
...




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