Lagom event latency

Lagom
1

Hi folks
Can anyone provide any information on the factors affecting event processing latency between Lagom producers and consumers?
In my tests with the sample Greeting app latency seems to be around the 10-12 second mark.

I found a reference in an old (c. 2 years) Google Groups topic to the cassandra-query-journal.eventual-consistency-delay setting which seems to be relevant: if I set this to 0 the latency decreases consistently to exactly (within a few ms) 3 seconds. That level of precision feels like a configuration setting rather than an accident, but I can’t find any reference configurations settings that seem related.

Can anyone share any info on what else is contributing to this delay?

2

@acgray check this topic

3

The 3 seconds is probably the poll interval https://github.com/akka/akka-persistence-cassandra/blob/release-0.50/core/src/main/resources/reference.conf#L548

You can also enable pub-sub notifications https://github.com/akka/akka-persistence-cassandra/blob/release-0.50/core/src/main/resources/reference.conf#L273

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