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Test set shows that optimal configuration is 2 containers with 2 KAFKA NUMBER_OF_PARTITIONS. 3 containers with 2 nodes shows higher response times than even one container with one partition. (same for 3 nodes with 3 partitions).

Partitioning logic depends on event types. It means that with "one call test" in any case we'll use only one partition of mod-pubsub. As for CheckIn-CheckOut test we might use one partition more than other (or other two) that can explain differences in CPU usages on different nodes. So bigger partition number can help with complex workflows or with real users. 

Version

mod-pubsub:1.3.3

Tests

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