Hi, So, I simplified the topology by making sure we have only 1 source topic. Now I have 1 source topic, 8 partitions, 2 instances. And here’s how the topology looks like:
instance 1: KafkaStreams processID: 48b58bc0-f600-4ec8-bc92-8cb3ea081aac StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-1 Active tasks: StreamsTask taskId: 0_3 ProcessorTopology: KSTREAM-SOURCE-0000000000: topics: [activities-avro-or] children: [KSTREAM-FILTER-0000000001] KSTREAM-FILTER-0000000001: children: [KSTREAM-MAP-0000000002] KSTREAM-MAP-0000000002: children: [KSTREAM-BRANCH-0000000003] KSTREAM-BRANCH-0000000003: children: [KSTREAM-BRANCHCHILD-0000000004, KSTREAM-BRANCHCHILD-0000000005] KSTREAM-BRANCHCHILD-0000000004: children: [KSTREAM-MAPVALUES-0000000006] KSTREAM-MAPVALUES-0000000006: children: [KSTREAM-FLATMAPVALUES-0000000007] KSTREAM-FLATMAPVALUES-0000000007: children: [KSTREAM-MAP-0000000008] KSTREAM-MAP-0000000008: children: [KSTREAM-FILTER-0000000011] KSTREAM-FILTER-0000000011: children: [KSTREAM-SINK-0000000010] KSTREAM-SINK-0000000010: topic: activities-by-phone-store-or-repartition KSTREAM-BRANCHCHILD-0000000005: Partitions [activities-avro-or-3] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-2 Active tasks: StreamsTask taskId: 1_2 ProcessorTopology: KSTREAM-SOURCE-0000000012: topics: [activities-by-phone-store-or-repartition] children: [KSTREAM-AGGREGATE-0000000009] KSTREAM-AGGREGATE-0000000009: states: [activities-by-phone-store-or] children: [KTABLE-TOSTREAM-0000000013] KTABLE-TOSTREAM-0000000013: children: [KSTREAM-FILTER-0000000014] KSTREAM-FILTER-0000000014: children: [KSTREAM-FILTER-0000000015] KSTREAM-FILTER-0000000015: children: [KSTREAM-MAP-0000000016] KSTREAM-MAP-0000000016: children: [KSTREAM-MAP-0000000017] KSTREAM-MAP-0000000017: children: [KSTREAM-SINK-0000000018] KSTREAM-SINK-0000000018: topic: ml-features-avro-or Partitions [activities-by-phone-store-or-repartition-2] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-3 Active tasks: StreamsTask taskId: 1_1 ProcessorTopology: KSTREAM-SOURCE-0000000012: topics: [activities-by-phone-store-or-repartition] children: [KSTREAM-AGGREGATE-0000000009] KSTREAM-AGGREGATE-0000000009: states: [activities-by-phone-store-or] children: [KTABLE-TOSTREAM-0000000013] KTABLE-TOSTREAM-0000000013: children: [KSTREAM-FILTER-0000000014] KSTREAM-FILTER-0000000014: children: [KSTREAM-FILTER-0000000015] KSTREAM-FILTER-0000000015: children: [KSTREAM-MAP-0000000016] KSTREAM-MAP-0000000016: children: [KSTREAM-MAP-0000000017] KSTREAM-MAP-0000000017: children: [KSTREAM-SINK-0000000018] KSTREAM-SINK-0000000018: topic: ml-features-avro-or Partitions [activities-by-phone-store-or-repartition-1] StreamsTask taskId: 2_7 ProcessorTopology: KSTREAM-SOURCE-0000000019: topics: [ml-features-avro-or] Partitions [ml-features-avro-or-7] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-4 Active tasks: StreamsTask taskId: 2_0 ProcessorTopology: KSTREAM-SOURCE-0000000019: topics: [ml-features-avro-or] Partitions [ml-features-avro-or-0] StreamsTask taskId: 2_6 ProcessorTopology: KSTREAM-SOURCE-0000000019: topics: [ml-features-avro-or] Partitions [ml-features-avro-or-6] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-5 Active tasks: StreamsTask taskId: 0_0 ProcessorTopology: KSTREAM-SOURCE-0000000000: topics: [activities-avro-or] children: [KSTREAM-FILTER-0000000001] KSTREAM-FILTER-0000000001: children: [KSTREAM-MAP-0000000002] KSTREAM-MAP-0000000002: children: [KSTREAM-BRANCH-0000000003] KSTREAM-BRANCH-0000000003: children: [KSTREAM-BRANCHCHILD-0000000004, KSTREAM-BRANCHCHILD-0000000005] KSTREAM-BRANCHCHILD-0000000004: children: [KSTREAM-MAPVALUES-0000000006] KSTREAM-MAPVALUES-0000000006: children: [KSTREAM-FLATMAPVALUES-0000000007] KSTREAM-FLATMAPVALUES-0000000007: children: [KSTREAM-MAP-0000000008] KSTREAM-MAP-0000000008: children: [KSTREAM-FILTER-0000000011] KSTREAM-FILTER-0000000011: children: [KSTREAM-SINK-0000000010] KSTREAM-SINK-0000000010: topic: activities-by-phone-store-or-repartition KSTREAM-BRANCHCHILD-0000000005: Partitions [activities-avro-or-0] StreamsTask taskId: 1_6 ProcessorTopology: KSTREAM-SOURCE-0000000012: topics: [activities-by-phone-store-or-repartition] children: [KSTREAM-AGGREGATE-0000000009] KSTREAM-AGGREGATE-0000000009: states: [activities-by-phone-store-or] children: [KTABLE-TOSTREAM-0000000013] KTABLE-TOSTREAM-0000000013: children: [KSTREAM-FILTER-0000000014] KSTREAM-FILTER-0000000014: children: [KSTREAM-FILTER-0000000015] KSTREAM-FILTER-0000000015: children: [KSTREAM-MAP-0000000016] KSTREAM-MAP-0000000016: children: [KSTREAM-MAP-0000000017] KSTREAM-MAP-0000000017: children: [KSTREAM-SINK-0000000018] KSTREAM-SINK-0000000018: topic: ml-features-avro-or Partitions [activities-by-phone-store-or-repartition-6] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-6 Active tasks: StreamsTask taskId: 1_0 ProcessorTopology: KSTREAM-SOURCE-0000000012: topics: [activities-by-phone-store-or-repartition] children: [KSTREAM-AGGREGATE-0000000009] KSTREAM-AGGREGATE-0000000009: states: [activities-by-phone-store-or] children: [KTABLE-TOSTREAM-0000000013] KTABLE-TOSTREAM-0000000013: children: [KSTREAM-FILTER-0000000014] KSTREAM-FILTER-0000000014: children: [KSTREAM-FILTER-0000000015] KSTREAM-FILTER-0000000015: children: [KSTREAM-MAP-0000000016] KSTREAM-MAP-0000000016: children: [KSTREAM-MAP-0000000017] KSTREAM-MAP-0000000017: children: [KSTREAM-SINK-0000000018] KSTREAM-SINK-0000000018: topic: ml-features-avro-or Partitions [activities-by-phone-store-or-repartition-0] StreamsTask taskId: 0_7 ProcessorTopology: KSTREAM-SOURCE-0000000000: topics: [activities-avro-or] children: [KSTREAM-FILTER-0000000001] KSTREAM-FILTER-0000000001: children: [KSTREAM-MAP-0000000002] KSTREAM-MAP-0000000002: children: [KSTREAM-BRANCH-0000000003] KSTREAM-BRANCH-0000000003: children: [KSTREAM-BRANCHCHILD-0000000004, KSTREAM-BRANCHCHILD-0000000005] KSTREAM-BRANCHCHILD-0000000004: children: [KSTREAM-MAPVALUES-0000000006] KSTREAM-MAPVALUES-0000000006: children: [KSTREAM-FLATMAPVALUES-0000000007] KSTREAM-FLATMAPVALUES-0000000007: children: [KSTREAM-MAP-0000000008] KSTREAM-MAP-0000000008: children: [KSTREAM-FILTER-0000000011] KSTREAM-FILTER-0000000011: children: [KSTREAM-SINK-0000000010] KSTREAM-SINK-0000000010: topic: activities-by-phone-store-or-repartition KSTREAM-BRANCHCHILD-0000000005: Partitions [activities-avro-or-7] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-7 Active tasks: StreamsTask taskId: 2_4 ProcessorTopology: KSTREAM-SOURCE-0000000019: topics: [ml-features-avro-or] Partitions [ml-features-avro-or-4] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-8 Active tasks: StreamsTask taskId: 1_3 ProcessorTopology: KSTREAM-SOURCE-0000000012: topics: [activities-by-phone-store-or-repartition] children: [KSTREAM-AGGREGATE-0000000009] KSTREAM-AGGREGATE-0000000009: states: [activities-by-phone-store-or] children: [KTABLE-TOSTREAM-0000000013] KTABLE-TOSTREAM-0000000013: children: [KSTREAM-FILTER-0000000014] KSTREAM-FILTER-0000000014: children: [KSTREAM-FILTER-0000000015] KSTREAM-FILTER-0000000015: children: [KSTREAM-MAP-0000000016] KSTREAM-MAP-0000000016: children: [KSTREAM-MAP-0000000017] KSTREAM-MAP-0000000017: children: [KSTREAM-SINK-0000000018] KSTREAM-SINK-0000000018: topic: ml-features-avro-or Partitions [activities-by-phone-store-or-repartition-3] Standby tasks: instance 2: KafkaStreams processID: 092072f8-87be-4989-a94f-0ed544f5ca44 StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-1 Active tasks: StreamsTask taskId: 2_1 ProcessorTopology: KSTREAM-SOURCE-0000000019: topics: [ml-features-avro-or] Partitions [ml-features-avro-or-1] StreamsTask taskId: 2_5 ProcessorTopology: KSTREAM-SOURCE-0000000019: topics: [ml-features-avro-or] Partitions [ml-features-avro-or-5] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-2 Active tasks: StreamsTask taskId: 0_4 ProcessorTopology: KSTREAM-SOURCE-0000000000: topics: [activities-avro-or] children: [KSTREAM-FILTER-0000000001] KSTREAM-FILTER-0000000001: children: [KSTREAM-MAP-0000000002] KSTREAM-MAP-0000000002: children: [KSTREAM-BRANCH-0000000003] KSTREAM-BRANCH-0000000003: children: [KSTREAM-BRANCHCHILD-0000000004, KSTREAM-BRANCHCHILD-0000000005] KSTREAM-BRANCHCHILD-0000000004: children: [KSTREAM-MAPVALUES-0000000006] KSTREAM-MAPVALUES-0000000006: children: [KSTREAM-FLATMAPVALUES-0000000007] KSTREAM-FLATMAPVALUES-0000000007: children: [KSTREAM-MAP-0000000008] KSTREAM-MAP-0000000008: children: [KSTREAM-FILTER-0000000011] KSTREAM-FILTER-0000000011: children: [KSTREAM-SINK-0000000010] KSTREAM-SINK-0000000010: topic: activities-by-phone-store-or-repartition KSTREAM-BRANCHCHILD-0000000005: Partitions [activities-avro-or-4] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-3 Active tasks: StreamsTask taskId: 2_2 ProcessorTopology: KSTREAM-SOURCE-0000000019: topics: [ml-features-avro-or] Partitions [ml-features-avro-or-2] StreamsTask taskId: 1_7 ProcessorTopology: KSTREAM-SOURCE-0000000012: topics: [activities-by-phone-store-or-repartition] children: [KSTREAM-AGGREGATE-0000000009] KSTREAM-AGGREGATE-0000000009: states: [activities-by-phone-store-or] children: [KTABLE-TOSTREAM-0000000013] KTABLE-TOSTREAM-0000000013: children: [KSTREAM-FILTER-0000000014] KSTREAM-FILTER-0000000014: children: [KSTREAM-FILTER-0000000015] KSTREAM-FILTER-0000000015: children: [KSTREAM-MAP-0000000016] KSTREAM-MAP-0000000016: children: [KSTREAM-MAP-0000000017] KSTREAM-MAP-0000000017: children: [KSTREAM-SINK-0000000018] KSTREAM-SINK-0000000018: topic: ml-features-avro-or Partitions [activities-by-phone-store-or-repartition-7] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-4 Active tasks: StreamsTask taskId: 2_3 ProcessorTopology: KSTREAM-SOURCE-0000000019: topics: [ml-features-avro-or] Partitions [ml-features-avro-or-3] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-5 Active tasks: StreamsTask taskId: 0_1 ProcessorTopology: KSTREAM-SOURCE-0000000000: topics: [activities-avro-or] children: [KSTREAM-FILTER-0000000001] KSTREAM-FILTER-0000000001: children: [KSTREAM-MAP-0000000002] KSTREAM-MAP-0000000002: children: [KSTREAM-BRANCH-0000000003] KSTREAM-BRANCH-0000000003: children: [KSTREAM-BRANCHCHILD-0000000004, KSTREAM-BRANCHCHILD-0000000005] KSTREAM-BRANCHCHILD-0000000004: children: [KSTREAM-MAPVALUES-0000000006] KSTREAM-MAPVALUES-0000000006: children: [KSTREAM-FLATMAPVALUES-0000000007] KSTREAM-FLATMAPVALUES-0000000007: children: [KSTREAM-MAP-0000000008] KSTREAM-MAP-0000000008: children: [KSTREAM-FILTER-0000000011] KSTREAM-FILTER-0000000011: children: [KSTREAM-SINK-0000000010] KSTREAM-SINK-0000000010: topic: activities-by-phone-store-or-repartition KSTREAM-BRANCHCHILD-0000000005: Partitions [activities-avro-or-1] StreamsTask taskId: 1_5 ProcessorTopology: KSTREAM-SOURCE-0000000012: topics: [activities-by-phone-store-or-repartition] children: [KSTREAM-AGGREGATE-0000000009] KSTREAM-AGGREGATE-0000000009: states: [activities-by-phone-store-or] children: [KTABLE-TOSTREAM-0000000013] KTABLE-TOSTREAM-0000000013: children: [KSTREAM-FILTER-0000000014] KSTREAM-FILTER-0000000014: children: [KSTREAM-FILTER-0000000015] KSTREAM-FILTER-0000000015: children: [KSTREAM-MAP-0000000016] KSTREAM-MAP-0000000016: children: [KSTREAM-MAP-0000000017] KSTREAM-MAP-0000000017: children: [KSTREAM-SINK-0000000018] KSTREAM-SINK-0000000018: topic: ml-features-avro-or Partitions [activities-by-phone-store-or-repartition-5] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-6 Active tasks: StreamsTask taskId: 1_4 ProcessorTopology: KSTREAM-SOURCE-0000000012: topics: [activities-by-phone-store-or-repartition] children: [KSTREAM-AGGREGATE-0000000009] KSTREAM-AGGREGATE-0000000009: states: [activities-by-phone-store-or] children: [KTABLE-TOSTREAM-0000000013] KTABLE-TOSTREAM-0000000013: children: [KSTREAM-FILTER-0000000014] KSTREAM-FILTER-0000000014: children: [KSTREAM-FILTER-0000000015] KSTREAM-FILTER-0000000015: children: [KSTREAM-MAP-0000000016] KSTREAM-MAP-0000000016: children: [KSTREAM-MAP-0000000017] KSTREAM-MAP-0000000017: children: [KSTREAM-SINK-0000000018] KSTREAM-SINK-0000000018: topic: ml-features-avro-or Partitions [activities-by-phone-store-or-repartition-4] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-7 Active tasks: StreamsTask taskId: 0_2 ProcessorTopology: KSTREAM-SOURCE-0000000000: topics: [activities-avro-or] children: [KSTREAM-FILTER-0000000001] KSTREAM-FILTER-0000000001: children: [KSTREAM-MAP-0000000002] KSTREAM-MAP-0000000002: children: [KSTREAM-BRANCH-0000000003] KSTREAM-BRANCH-0000000003: children: [KSTREAM-BRANCHCHILD-0000000004, KSTREAM-BRANCHCHILD-0000000005] KSTREAM-BRANCHCHILD-0000000004: children: [KSTREAM-MAPVALUES-0000000006] KSTREAM-MAPVALUES-0000000006: children: [KSTREAM-FLATMAPVALUES-0000000007] KSTREAM-FLATMAPVALUES-0000000007: children: [KSTREAM-MAP-0000000008] KSTREAM-MAP-0000000008: children: [KSTREAM-FILTER-0000000011] KSTREAM-FILTER-0000000011: children: [KSTREAM-SINK-0000000010] KSTREAM-SINK-0000000010: topic: activities-by-phone-store-or-repartition KSTREAM-BRANCHCHILD-0000000005: Partitions [activities-avro-or-2] StreamsTask taskId: 0_6 ProcessorTopology: KSTREAM-SOURCE-0000000000: topics: [activities-avro-or] children: [KSTREAM-FILTER-0000000001] KSTREAM-FILTER-0000000001: children: [KSTREAM-MAP-0000000002] KSTREAM-MAP-0000000002: children: [KSTREAM-BRANCH-0000000003] KSTREAM-BRANCH-0000000003: children: [KSTREAM-BRANCHCHILD-0000000004, KSTREAM-BRANCHCHILD-0000000005] KSTREAM-BRANCHCHILD-0000000004: children: [KSTREAM-MAPVALUES-0000000006] KSTREAM-MAPVALUES-0000000006: children: [KSTREAM-FLATMAPVALUES-0000000007] KSTREAM-FLATMAPVALUES-0000000007: children: [KSTREAM-MAP-0000000008] KSTREAM-MAP-0000000008: children: [KSTREAM-FILTER-0000000011] KSTREAM-FILTER-0000000011: children: [KSTREAM-SINK-0000000010] KSTREAM-SINK-0000000010: topic: activities-by-phone-store-or-repartition KSTREAM-BRANCHCHILD-0000000005: Partitions [activities-avro-or-6] Standby tasks: StreamsThread appId: mar-23-modular StreamsThread clientId: mar-23-modular StreamsThread threadId: StreamThread-8 Active tasks: StreamsTask taskId: 0_5 ProcessorTopology: KSTREAM-SOURCE-0000000000: topics: [activities-avro-or] children: [KSTREAM-FILTER-0000000001] KSTREAM-FILTER-0000000001: children: [KSTREAM-MAP-0000000002] KSTREAM-MAP-0000000002: children: [KSTREAM-BRANCH-0000000003] KSTREAM-BRANCH-0000000003: children: [KSTREAM-BRANCHCHILD-0000000004, KSTREAM-BRANCHCHILD-0000000005] KSTREAM-BRANCHCHILD-0000000004: children: [KSTREAM-MAPVALUES-0000000006] KSTREAM-MAPVALUES-0000000006: children: [KSTREAM-FLATMAPVALUES-0000000007] KSTREAM-FLATMAPVALUES-0000000007: children: [KSTREAM-MAP-0000000008] KSTREAM-MAP-0000000008: children: [KSTREAM-FILTER-0000000011] KSTREAM-FILTER-0000000011: children: [KSTREAM-SINK-0000000010] KSTREAM-SINK-0000000010: topic: activities-by-phone-store-or-repartition KSTREAM-BRANCHCHILD-0000000005: Partitions [activities-avro-or-5] Standby tasks: activities-avro-or is input topic. ml-features-avro-or is output topic. In the middle we have an aggregate (activities-by-phone-store-or-repartition). On instance 1 I see 3 tasks for activities-avro-or and on instance 2 I see 5. Bad. On instance 1 see 4 tasks for ml-features-avro-or. And 4 on instance 2. Good. On instance 1 see 5 tasks for activities-by-phone-store-or-repartition. And 3 on instance 2. Bad. As I said in terms of offsets for all these partitions I see uniform distribution, so we’re not dealing with a bad key scenario. Ara. On Mar 25, 2017, at 6:43 PM, Matthias J. Sax <matth...@confluent.io<mailto:matth...@confluent.io>> wrote: ________________________________ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the e-mail by you is prohibited. Thank you in advance for your cooperation. ________________________________ From: "Matthias J. Sax" <matth...@confluent.io<mailto:matth...@confluent.io>> Subject: Re: more uniform task assignment across kafka stream nodes Date: March 25, 2017 at 6:43:12 PM PDT To: users@kafka.apache.org<mailto:users@kafka.apache.org> Reply-To: <users@kafka.apache.org<mailto:users@kafka.apache.org>> Please share the rest of your topology code (without any UDFs / business logic). Otherwise, I cannot give further advice. -Matthias On 3/25/17 6:08 PM, Ara Ebrahimi wrote: Via: builder.stream("topic1"); builder.stream("topic2"); builder.stream("topic3”); These are different kinds of topics consuming different avro objects. Ara. On Mar 25, 2017, at 6:04 PM, Matthias J. Sax <matth...@confluent.io<mailto:matth...@confluent.io><mailto:matth...@confluent.io>> wrote: ________________________________ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the e-mail by you is prohibited. Thank you in advance for your cooperation. ________________________________ From: "Matthias J. Sax" <matth...@confluent.io<mailto:matth...@confluent.io><mailto:matth...@confluent.io>> Subject: Re: more uniform task assignment across kafka stream nodes Date: March 25, 2017 at 6:04:30 PM PDT To: users@kafka.apache.org<mailto:users@kafka.apache.org><mailto:users@kafka.apache.org> Reply-To: <users@kafka.apache.org<mailto:users@kafka.apache.org><mailto:users@kafka.apache.org>> Ara, How do you consume your topics? Via builder.stream("topic1", "topic2", "topic3); or via builder.stream("topic1"); builder.stream("topic2"); builder.stream("topic3"); Both and handled differently with regard to creating tasks (partition to task assignment also depends on you downstream code though). If this does not help, can you maybe share the structure of processing? To dig deeper, we would need to know the topology DAG. -Matthias On 3/25/17 5:56 PM, Ara Ebrahimi wrote: Mathias, This apparently happens because we have more than 1 source topic. We have 3 source topics in the same application. So it seems like the task assignment algorithm creates topologies not for one specific topic at a time but the total partitions across all source topics consumed in an application instance. Because we have some code dependencies between these 3 source topics we can’t separate them into 3 applications at this time. Hence the reason I want to get the task assignment algorithm basically do a uniform and simple task assignment PER source topic. Ara. On Mar 25, 2017, at 5:21 PM, Matthias J. Sax <matth...@confluent.io<mailto:matth...@confluent.io><mailto:matth...@confluent.io><mailto:matth...@confluent.io>> wrote: ________________________________ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the e-mail by you is prohibited. Thank you in advance for your cooperation. ________________________________ From: "Matthias J. Sax" <matth...@confluent.io<mailto:matth...@confluent.io><mailto:matth...@confluent.io><mailto:matth...@confluent.io>> Subject: Re: more uniform task assignment across kafka stream nodes Date: March 25, 2017 at 5:21:47 PM PDT To: users@kafka.apache.org<mailto:users@kafka.apache.org><mailto:users@kafka.apache.org><mailto:users@kafka.apache.org> Reply-To: <users@kafka.apache.org<mailto:users@kafka.apache.org><mailto:users@kafka.apache.org><mailto:users@kafka.apache.org>> Hi, I am wondering why this happens in the first place. Streams, load-balanced over all running instances, and each instance should be the same number of tasks (and thus partitions) assigned. What is the overall assignment? Do you have StandyBy tasks configured? What version do you use? -Matthias On 3/24/17 8:09 PM, Ara Ebrahimi wrote: Hi, Is there a way to tell kafka streams to uniformly assign partitions across instances? If I have n kafka streams instances running, I want each to handle EXACTLY 1/nth number of partitions. No dynamic task assignment logic. Just dumb 1/n assignment. Here’s our scenario. Lets say we have an “source" topic with 8 partitions. We also have 2 kafka streams instances. Each instances get assigned to handle 4 “source" topic partitions. BUT then we do a few maps and an aggregate. So data gets shuffled around. The map function uniformly distributes these across all partitions (I can verify that by looking at the partition offsets). After the map what I notice by looking at the topology is that one kafka streams instance get assigned to handle say 2 aggregate repartition topics and the other one gets assigned 6. Even worse, on bigger clusters (say 4 instances) we see say 2 nodes gets assigned downstream aggregate repartition topics and 2 other nodes assigned NOTHING to handle. Ara. ________________________________ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the e-mail by you is prohibited. Thank you in advance for your cooperation. ________________________________ ________________________________ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the e-mail by you is prohibited. Thank you in advance for your cooperation. ________________________________ ________________________________ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the e-mail by you is prohibited. Thank you in advance for your cooperation. ________________________________ ________________________________ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the e-mail by you is prohibited. Thank you in advance for your cooperation. ________________________________
