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From Gagan Agrawal <agrawalga...@gmail.com>
Subject Buffer stats when Back Pressure is high
Date Mon, 07 Jan 2019 04:05:50 GMT
Hi,
I want to understand does any of buffer stats help in debugging /
validating that downstream operator is performing slow when Back Pressure
is high? Say I have A -> B operators and A shows High Back Pressure which
indicates something wrong or not performing well on B side which is slowing
down operator A. However when I look at buffers.inputQueueLength for
operator B, it's 0. My understanding is that when B is processing slow,
it's input buffer will be full of incoming messages which ultimately
blocks/slows down upstream operator A. However it doesn't seem to be
happening in my case. Can someone throw some light on how should different
stats around buffers (e.g buffers.inPoolUsage, buffers.inputQueueLength,
numBuffersInLocalPerSecond, numBuffersInRemotePerSecond) look like when
downstream operator is performing slow?

Gagan

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