Thanks Fabian but for 1.5k messages per second per TM there are several million Internal & TimerWindow objects created within a period of 5 seconds. Is there a way to get debug this issue?
Regards, Navneeth On Tue, Jan 23, 2018 at 2:09 AM, Fabian Hueske <fhue...@gmail.com> wrote: > Hi, > > TimeWindows and Timers are created for each window, i.e., every 5 seconds > for every distinct key that a task is processing. > Event-time windows are completed and cleaned up when a watermark is > received that passes the window end timestamp. > Therefore, there might be more than one window per key depending on the > watermarks. > > Hope this helps, > Fabian > > 2018-01-21 6:48 GMT+01:00 Navneeth Krishnan <reachnavnee...@gmail.com>: > >> 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$Node >> 7: 804203 19300872 java.lang.String >> 8: 541651 17332832 org.apache.flink.streaming.api >> .operators.InternalTimer >> 9: 540252 17288064 org.apache.flink.streaming.api >> .windowing.windows.TimeWindow >> >> >> *Captured at T1 (T + 5 seconds):* >> >> num #instances #bytes class name >> ---------------------------------------------- >> 1: 12084258 2282849264 <(228)%20284-9264> [B >> 2: 1922018 1828760896 [D >> 3: 68261427 1092182832 java.lang.Integer >> 4: 2712099 291488736 [C >> 5: 54201 98798976 [I >> 6: 2028250 48678000 java.lang.String >> 7: 66080 43528136 [[B >> 8: 1401915 35580168 [Ljava.lang.Object; >> 9: 949062 30369984 java.util.HashMap$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. >> >> >
