Re: ProcessWindowFunction中如何有效清除state呢

[Yun Tang]

Hi

从代码看 if(stateDate.equals("") || stateDate.equals(date)) 
无法判断究竟是从哪里获取到stateDate变量赋值，不清楚你这里里面的判断逻辑是否能生效。
其次，state.clear() 之后，再次获取时，返回值会是null，代码片段里面也没有看出来哪里有对这个的校验。

祝好
唐云
________________________________
From: 守护 <346531...@qq.com>
Sent: Tuesday, March 31, 2020 12:33
To: user-zh <user-zh@flink.apache.org>
Subject: ProcessWindowFunction中如何有效清除state呢

各位好：


--版本
FLINK 1.10.0 ON YARN


--过程
1.定义一个&nbsp; .window(TumblingProcessingTimeWindows.of(Time.days(1)))窗口
2.定义一个new 
Trigger(），.trigger(ContinuousProcessingTimeTrigger.of(Time.minutes(10)))
3.定义一个new ProcessWindowFunction(),每隔固定时间计算一次，业务是每天0点开始算这一天的数据，第二天清空从新计算，
--问题
&nbsp;在 new 
ProcessWindowFunction()中创建了ValueState，想在第二天0点的时候ValueState清空开始重新计算，但是返现ValueState并没有清空，而是叠加前一天的继续计算，这个.clear()方法应该在什么时候加，才能生效呢？



--部分代码


  .window(TumblingProcessingTimeWindows.of(Time.days(1)))   
.trigger(ContinuousProcessingTimeTrigger.of(Time.minutes(10)))
.process(new ProcessWindowFunction[(String,String,Long), String, Tuple, 
TimeWindow] {


&nbsp; &nbsp; &nbsp; &nbsp; private var pv_st: ValueState[Long] = _&nbsp; 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;


&nbsp; &nbsp; &nbsp; &nbsp; override def open(parameters: Configuration): Unit 
= {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;pv_st = getRuntimeContext.getState[Long](new 
ValueStateDescriptor[Long]("pv_stCount", classOf[Long]))
&nbsp; &nbsp; &nbsp; &nbsp; }


&nbsp; &nbsp; &nbsp; &nbsp;override def process(key: Tuple, context: Context, 
elements: Iterable[(String,String,Long)], out: Collector[String]): Unit = {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var c_st = 0
&nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; val elementsIterator = elements.iterator
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; // 遍历窗口数据，获取唯一word
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; while (elementsIterator.hasNext) {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; val ac_name = 
elementsIterator.next()._2
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(!ac_name.isEmpty &amp;&amp; 
ac_name.equals("listentime")){
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; c_st +=1
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; val time: Date = new Date()
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; val dateFormat: SimpleDateFormat = new 
SimpleDateFormat("yyyy-MM-dd")
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; val date = dateFormat.format(time)


&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; // add current
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;pv_st.update(pv_st.value() + c_st)


&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var jsonStr = 
""+key.getField(0)+"_"+date+"&amp;" // json格式开始
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; jsonStr += "{"+
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
"\"yesterday_foreground_play_pv\":\""+pv_st.value()+
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "\"}";




&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //判断逻辑，是否到第二天，如果到第二天状态数据全部清空，重新累加
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(stateDate.equals("") || 
stateDate.equals(date)){
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; stateDate=date
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; out.collect(jsonStr)
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }else{
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; out.collect(jsonStr)
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; pv_st.clear()
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; stateDate=date
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }


&nbsp; &nbsp; &nbsp; &nbsp; }


&nbsp; &nbsp; &nbsp; })