本地调试报错

Caused by: java.io.IOException: Insufficient number of network buffers: required 9, but only 0 available. The total number of network buffers is currently set to 2048 of 32768 bytes each. You can increase this number by setting the configuration keys 'taskmanager.memory.network.fraction', 'taskmanager.memory.network.min', and 'taskmanager.memory.network.max'.
    at org.apache.flink.runtime.io.network.buffer.NetworkBufferPool.internalCreateBufferPool(NetworkBufferPool.java:357)
    at org.apache.flink.runtime.io.network.buffer.NetworkBufferPool.createBufferPool(NetworkBufferPool.java:332)
    at org.apache.flink.runtime.io.network.partition.ResultPartitionFactory.lambda$createBufferPoolFactory$0(ResultPartitionFactory.java:224)
    at org.apache.flink.runtime.io.network.partition.ResultPartition.setup(ResultPartition.java:146)
    at org.apache.flink.runtime.taskmanager.Task.setupPartitionsAndGates(Task.java:869)
    at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:635)
    at org.apache.flink.runtime.taskmanager.Task.run(Task.java:546)
    at java.lang.Thread.run(Thread.java:748)

原因： 系统自动分配并行度，test模式下无法申请足够的slot 无法运行，
env.setParallelism(1); 即可解决问题