FlinkToMySql两阶段提交

Posted 2022-06-01 今天好好洗头了嘛

版本

Flink1.10

实现

1. 继承TwoPhaseCommitSinkFunction
2. 实现invoke()、beginTransaction()、preCommit()、commit()、abort()等方法

流程

beginTransaction---->preCommit，同时开启下一次beginTransaction---->commit---->preCommit，同时开启下一次beginTransaction---->commit。。。。。。
大概理解是下边这个流程
beginTransaction，invoke，preCommit，commit(第一次checkpoint)
---------------------------------------------------->beginTransaction，invoke，preCommit，commit(第二次checkpoint)
---------------------------------------------------------------------------------------------------------->beginTransaction，invoke，preCommit，commit(第三次checkpoint)

注意：
1、如果commit期间有异常，则重试commit方法。
2、如果invoke期间有异常，则回滚到上一个checkpoint，执行一下上一个checkpoint的commit方法(很奇怪，没理解这里)，然后进行重试后续的数据。

代码测试

public abstract class MyTwoPhaseCommitSinkFunction<IN> extends TwoPhaseCommitSinkFunction<IN, List<IN>, Void> 
    public MyTwoPhaseCommitSinkFunction() 
        super((TypeSerializer<List<IN>>) new KryoSerializer<IN>((Class<IN>) List.class, new ExecutionConfig()), VoidSerializer.INSTANCE);
    


    @Override
    protected void invoke(List<IN> list, IN value, Context context) throws Exception 
        System.err.println("invoke开始......"+list);
        list.add(value);
        System.err.println("invoke结束......"+list);
    

    @Override
    protected List<IN> beginTransaction() throws Exception 
        System.err.println("beginTransaction......");
        return new ArrayList<>();
    

    @Override
    protected void preCommit(List<IN> list) throws Exception 
        System.err.println("preCommit......"+list);
    



    @Override
    protected void abort(List<IN> list) 
        System.err.println("abort......"+list);
    

public class App 
    public static void main(String[] args) throws Exception 
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);
        env.enableCheckpointing( 5000, CheckpointingMode.EXACTLY_ONCE);
        env.setStateBackend(new FsStateBackend("file:///C:/Jian_Coding/Flink/Study/checkpoint"));
        SingleOutputStreamOperator<String> sourceDS = env.addSource(MyKafkaUtil.getKafkaSource()).name("kafkaSourceFun");
        sourceDS.addSink(new MyTwoPhaseCommitSinkFunction<String>() 
            @Override
            protected void commit(List<String> list) 
/*                long l = System.currentTimeMillis();
                if(l%2==0)
                    int i = 1/0;
                */
                System.err.println("commit......"+list);
            
        );
        env.execute();