Hi, I'm facing issues with frequent young generation garbage collections in my task manager which happens approximately every few seconds. I have 3 task managers with 12GB heap allocated on each and I have set the config to use G1GC. My program ingests binary data from kafka source and the message rate is around 4.5k msgs/sec with around 400 bytes per msg. Below are the operators used in the program.
kafka src -> keyby -> CoProcess -> keyby -> Tumbling Window (5secs) -> FlatMap -> Sink I captured the below histograms at 5 second intervals and analyzed the heap as well. It looks like a lot InternalTimer and TimeWindow objects are created. Also, I see a high usage in org.apache.flink.streaming.api.operators.HeapInternalTimerService. *Window code:* dataStream.keyBy(new MessageKeySelector()) .window(TumblingEventTimeWindows.of(Time.seconds(5))) .apply(new Aggregate()); *Captured at time T:* num #instances #bytes class name ---------------------------------------------- 1: 2074427 481933816 [B 2: 357192 339368592 [D 3: 12759222 204147552 java.lang.Integer 4: 31416 85151832 [I 5: 900982 83872240 [C 6: 631888 20220416 java.util.HashMap$Node 7: 804203 19300872 java.lang.String 8: 541651 17332832 org.apache.flink.streaming.api.operators.InternalTimer 9: 540252 17288064 org.apache.flink.streaming.api.windowing.windows.TimeWindow *Captured at T1 (T + 5 seconds):* num #instances #bytes class name ---------------------------------------------- 1: 12084258 2282849264 [B 2: 1922018 1828760896 [D 3: 68261427 1092182832 java.lang.Integer 4: 2712099 291488736 [C 5: 54201 98798976 [I 6: 2028250 48678000 java.lang.String 7: 66080 43528136 [[B 8: 1401915 35580168 [Ljava.lang.Object; 9: 949062 30369984 java.util.HashMap$Node 10: 570832 18266624 org.apache.flink.streaming.api.operators.InternalTimer 11: 549979 17599328 org.apache.flink.streaming.api.windowing.windows.TimeWindow *Captured at T2 (T1+ 5 seconds):* num #instances #bytes class name ---------------------------------------------- 1: 9911982 2920384472 [B 2: 1584406 1510958520 [D 3: 56087337 897397392 java.lang.Integer 4: 26080337 834570784 java.util.HashMap$Node 5: 25756748 824215936 org.apache.flink.streaming.api.operators.InternalTimer 6: 25740086 823682752 org.apache.flink.streaming.api.windowing.windows.TimeWindow Thanks.