Need Help Understanding Storm UI (0.8.1) for Trident Topology

[Ryan Ebanks]

Hi,

I have attached a small .png file of part of my StormUI display that I need help understand.  Under the header "Spouts", there is a row with the id "$mastercoord-bg0".  My understanding is that this is the coordinator that determines if an entire batch failed, is this correct?

Under the header "Bolts", there is a row with the id "$spoutcoord-spout0".  What is this, and what is emitted, transfered, and acked from this?

When looking at the numbers acked and emitted notice that no counts for failed have appeared under the Bolts heading, but only counts for failed appear under the "Spouts" heading.  Is this an indicator that all functions/filters/etc. are probably working correctly but are timing out?  What other causes would show that all emits are being Acked in the Bolts but all emitts are failing in the Spouts.  

I am running storm 0.8.1.  Thank you for the help.

-Ryan

[Beck Chen]

I have the exact same question.

[Flip Kromer]

the MasterBatchCoordinator is generic for all trident topologies; the spout coordinator is specific to your type of spout. For example, the kafka spout coordinator knows what offset and partitions should be read next.

A trident "spout" is actually a bolt, as is the spout coordinator -- all their tuples belong to the tupletree of the seed tuple the MBCoordinator dispenses. 

In the screenshot, that spout has emitted 200k tuples, but only 69k tuples were acked; batches are timing out.

flip