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From Jun Wu <>
Subject RE: How to get information of each read/write request?
Date Tue, 30 Aug 2016 21:27:20 GMT
Hi Chris,
      Thank you so much for the reply.  For the tracing on in cqlsh, it gives a very high-level
information. I do need more other detailed information.
      For the ticket, that's exactly what I want: the waiting time for the thread pool queue.
Actually I do want to the waiting time for each stage for each query. That could be awesome.
      Again, your information is quite useful. Thanks!

Date: Tue, 30 Aug 2016 14:31:17 -0500
Subject: Re: How to get information of each read/write request?

Running a query with trace (`TRACING ON` in cqlsh) can give you a lot of the information for
an individual request. There has been a ticket to track time in queue (
but no ones worked on it yet.
On Tue, Aug 30, 2016 at 12:20 PM, Jun Wu <> wrote:

Hi there,
     I'm very interested in the read/write path of Cassandra. Specifically, I'd like to know
the whole process when a read/write request comes in. 
    I noticed that for reach request it could go through multiple stages. For example, for
read request, it could be in ReadStage, RequestResponseStage, ReadRepairStage. For each stage,
actually it's a queue and thread pool to serve the request. 
   First question is how to track each request in which stage.    Also I'm very interested
int the waiting time for each request to be in the queue, also the total queue in each stage.
I noticed that in nodetool tpstats will have this information. However, I may want to get
the real-time information of this, like print it out in the terminal. 
    I'm wondering  whether someone has hints on this. 
   Thanks in advance!

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