flink job正常运行了好久，突然一天发生的异常，查看据异常信息，发现是内存模型出现了问题，根据日志提示修改了几个值，从而解决了问题
报错信息
java.io.IOException: Timeout triggered when requesting exclusive buffers: The total number of network buffers is currently set to 22773 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', or you may increase the timeout which is 30000ms by setting the key 'taskmanager.network.memory.exclusive-buffers-request-t imeout-ms'
解决办法
StreamExecutionEnvironment environment = StreamExecutionEnvironment.getExecutionEnvironment();
Configuration conf = new Configuration();
conf.setString("taskmanager.memory.network.min", "128MB");
conf.setString("taskmanager.memory.network.max", "2GB");
conf.setString("taskmanager.network.memory.exclusive-buffers-request-timeout-ms", "30000ms");
environment.getConfig().setGlobalJobParameters(conf);
taskmanager.memory.network.min：网络缓存的最小值，默认64MB；
taskmanager.memory.network.max：网络缓存的最大值，默认1GB；
taskmanager.memory.network.fraction：网络缓存占Flink总内存taskmanager.memory.flink.size的比例，默认值0.1。上面两个设置过了，本项会被覆盖，两者设置其一即可。
分别给它提高了一倍
并设置了超时时间为30000ms
