warnings.print() 以相反的顺序打印事件（最后一个事件在前）除了 Apache Flink CEP 中的第一个事件

Question

我正在尝试使用以下模式过滤 Flink 中大于 10 的所有临时事件，

Pattern<MonitoringEvent, ?> warningPattern = Pattern.<MonitoringEvent>begin("first")
                .subtype(TemperatureEvent.class)
                .where(new FilterFunction<TemperatureEvent>() {
                    @Override
                    public boolean filter(TemperatureEvent temperatureEvent) throws Exception {
                        return temperatureEvent.getTemperature() > 50;
                    }
                });

输入是文本文件，通过输入函数解析为流，输入文件内容为：-

1,98
2,33
3,44
4,55
5,66
6,88
7,99
8,76

这里的第一个值是 Rack_id，第二个是温度

我已经在输入流和 WarnigsStream 上发出了 print() ，如下所示

inputEventStream.print();
warnings.print();

问题来了，Flink CEP的输出如下图

08/10/2017 23:43:15 Job execution switched to status RUNNING.
08/10/2017 23:43:15 Source: Custom Source -> Sink: Unnamed(1/1) switched to SCHEDULED 
08/10/2017 23:43:15 Source: Custom Source -> Sink: Unnamed(1/1) switched to DEPLOYING 
08/10/2017 23:43:15 AbstractCEPPatternOperator -> Map -> Sink: Unnamed(1/1) switched to SCHEDULED 
08/10/2017 23:43:15 AbstractCEPPatternOperator -> Map -> Sink: Unnamed(1/1) switched to DEPLOYING 
08/10/2017 23:43:15 AbstractCEPPatternOperator -> Map -> Sink: Unnamed(1/1) switched to RUNNING 
08/10/2017 23:43:15 Source: Custom Source -> Sink: Unnamed(1/1) switched to RUNNING 
Rack id = 1 and temprature = 98.0)
Rack id = 2 and temprature = 33.0)
Rack id = 3 and temprature = 44.0)
Rack id = 4 and temprature = 55.0)
Rack id = 5 and temprature = 66.0)
Rack id = 6 and temprature = 88.0)
Rack id = 7 and temprature = 99.0)
Rack id = 8 and temprature = 76.0)
08/10/2017 23:43:16 Source: Custom Source -> Sink: Unnamed(1/1) switched to FINISHED 
Rack id = 1 and temprature = 98.0)
Rack id = 8 and temprature = 76.0)
Rack id = 7 and temprature = 99.0)
Rack id = 6 and temprature = 88.0)
Rack id = 5 and temprature = 66.0)
Rack id = 4 and temprature = 55.0)
08/10/2017 23:43:16 AbstractCEPPatternOperator -> Map -> Sink: Unnamed(1/1) switched to FINISHED 
08/10/2017 23:43:16 Job execution switched to status FINISHED.

Process finished with exit code 0

正如我们所见，第一个复杂事件（Rack id = 1 and temperature = 98.0））以相同的顺序打印，但在此之后，所有其他具有 temp > 50 的复杂事件都以相反的顺序打印关于输入流。

My questions are :-

1. Any idea why events are getting printed in reverse order?
2. Is there a custom way to print values{w/o using warnings.print()} of 
   warning stream, like can I print only temperature, rather than rack-id ?

提前致谢

Answer 1

此问题已通过将时间戳和水印分配给 inputStream 解决，如下所示

// Input stream of monitoring events
        DataStream<MonitoringEvent> inputEventStream = env
                .addSource(new InputStreamAGenerator()).assignTimestampsAndWatermarks(new IngestionTimeExtractor<>());

生成的输出如下所示

 08/11/2017 00:45:09    Job execution switched to status RUNNING.
    08/11/2017 00:45:09 Source: Custom Source -> Timestamps/Watermarks(1/1) switched to SCHEDULED 
    08/11/2017 00:45:09 Source: Custom Source -> Timestamps/Watermarks(1/1) switched to DEPLOYING 
    08/11/2017 00:45:09 AbstractCEPPatternOperator -> Map -> Sink: Unnamed(1/1) switched to SCHEDULED 
    08/11/2017 00:45:09 AbstractCEPPatternOperator -> Map -> Sink: Unnamed(1/1) switched to DEPLOYING 
    08/11/2017 00:45:09 Source: Custom Source -> Timestamps/Watermarks(1/1) switched to RUNNING 
    08/11/2017 00:45:09 AbstractCEPPatternOperator -> Map -> Sink: Unnamed(1/1) switched to RUNNING 
    Rack id = 1 and temprature = 98.0)
    Rack id = 4 and temprature = 55.0)
    Rack id = 5 and temprature = 66.0)
    Rack id = 6 and temprature = 88.0)
    Rack id = 7 and temprature = 99.0)
    Rack id = 8 and temprature = 76.0)
    08/11/2017 00:45:10 Source: Custom Source -> Timestamps/Watermarks(1/1) switched to FINISHED 
    08/11/2017 00:45:10 AbstractCEPPatternOperator -> Map -> Sink: Unnamed(1/1) switched to FINISHED 
    08/11/2017 00:45:10 Job execution switched to status FINISHED.

warnings.print() 以相反的顺序打印事件（最后一个事件在前）除了 Apache Flink CEP 中的第一个事件

warnings.print() prints events in reverse order(last event first ) excepts first event in Apache Flink CEP

complex-event-processing

apache-flink

flink-streaming

flink-cep