Github user zentol commented on a diff in the pull request:
https://github.com/apache/flink/pull/4826#discussion_r145114263
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/util/latency/LatencyStats.java
---
@@ -0,0 +1,67 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.streaming.util.latency;
+
+import org.apache.flink.metrics.MetricGroup;
+import org.apache.flink.streaming.runtime.streamrecord.LatencyMarker;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * The {@link LatencyStats} objects are used to track and report on the
behavior of latencies across measurements.
+ */
+public class LatencyStats {
+ private final Map<String, LatencyHistogram> latencyStats = new
HashMap<>();
+ private final MetricGroup metricGroup;
+ private final int historySize;
+
+ public LatencyStats(MetricGroup metricGroup, int historySize) {
+ this.metricGroup = metricGroup;
+ this.historySize = historySize;
+ }
+
+ public void reportLatency(LatencyMarker marker, boolean isSink) {
+ String latencyMetricName = identifyLatencySource(marker,
!isSink);
+ LatencyHistogram latencyHistogram =
this.latencyStats.get(latencyMetricName);
+ if (latencyHistogram == null) {
+ latencyHistogram = new
LatencyHistogram(this.historySize);
+ this.latencyStats.put(latencyMetricName,
latencyHistogram);
+ this.metricGroup.histogram(latencyMetricName,
latencyHistogram);
+ }
+
+ long now = System.currentTimeMillis();
+ latencyHistogram.update(now - marker.getMarkedTime());
+ }
+
+ /**
+ * Creates a Identifier for a latency source. from a given {@code
LatencyMarker}.
--- End diff --
"an identifier"
---
