Hi,

Are the latency and throughput metrics of a topology available in Nimbus?
I'm working on a dynamic load-balancer running within Nimbus. To make
intelligent decisions, I need these two metrics along with a few others.

>From digging into the code, I found "SpoutStats" made available through
TopologyInfo. I would like to know if my understanding about the fields in
SpoutStats is correct.

acked - This is an aggregate number of the spout-tuples that completed the
tuple-tree.

failed - This is an aggregate number of the spout-tuples that failed to
complete the tuple-tree

complete_ms_avg - The avg time from when the tuple was emitted by the spout
to the time when the tuple-tree is completed.

1. By periodically getting the acked value I can calculate the throughput
of the topology for that period.
2. complete_ms_avg gives an accurate representation of the latency.

It will be great if someone can validate my understanding.

Thanks,
Anirudh

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