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input-output-hk / cardano-rt-view

RTView: real-time watching for Cardano nodes (ARCHIVED)
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Question About Missed Slots Displayed at the Turn of the Epoch #137

Open rickymac68 opened 3 years ago

rickymac68 commented 3 years ago

Hi, I have a question about the missed slots at the turn of the epoch displayed in RTView. Are the missed slots actually missed by the block producer? Or are the logged missed slots by RTView, where RTView did not see the reports from the block producers.

The reason I ask is that I only see missed slots at the turn of the epoch, and it varies by block producer. Picture attached of block producers to show what I am saying.

To be clear, I am not missing slots during the course of the epoch. These 27 to 31 missed slots showing ONLY showed up during the turn of the current epoch.

I guess another question is... What does "missed slot" even mean on RTView? Because we are hitting our assigned blocks.

Thanks!

Screenshot from 2021-01-02 11-43-17

denisshevchenko commented 3 years ago

What does "missed slot" even mean on RTView?

@rickymac68 This is the value received from the node. This is where that value comes from: https://github.com/input-output-hk/cardano-node/blob/master/cardano-node/src/Cardano/Tracing/Tracers.hs#L668. So, RTView doesn't make any calculations on it - no, it just receives a number and displays it. And if this number is calculated somehow improperly - it should be fixed in cardano-node repository, not here...

deepfire commented 3 years ago

@rickymac68, missed slots are different from missed blocks -- those are slots, where the node was unable to timely determine if it was a leader or not.

deepfire commented 3 years ago

@rickymac68, so, to expand further -- given that we know that the system is sometimes subject to load spikes, it's natural for those to happen.

IOW, it's normal behavior, from standpoint of tracing.

Now, the question of load spikes that cause this situation is entirely separate, and a longer story..

denisshevchenko commented 3 years ago

So, @deepfire, does it mean that this issue can be closed?

cyanitol commented 3 years ago

I also have questions on this as well. What is an acceptable amount of slots to miss for a producer?