Hi Bobby, I am running a simple word count topology. I have 2 worker nodes and a nimbus/zookeeper node. The latency between the nodes is < 1ms.
I have synched the clocks of all 3 nodes using NTP. Is this not sufficient ? Thanks, Preethini On Mon, Jul 24, 2017 at 5:22 PM, Bobby Evans <[email protected]> wrote: > It is really hard to tell without more information. Off the top of my > head it might have something to do with the system time on different > hosts. Getting the current time in milliseconds is full of issues, > especially with leap seconds etc, but it is even more problematic between > machines because the time is not guaranteed to be synced very closely. > That would be my first guess. If they are all on the same machine (you are > not switching hosts), then my next guess would be a bug in the code some > where, or a misinterpretation of the results. > > Do you have a reproducible use case that you can share? > > - Bobby > > > > On Monday, July 24, 2017, 10:13:59 AM CDT, preethini v < > [email protected]> wrote: > > > Hi, > > I measure the latency of a storm topology in the below two ways. And I see > a huge difference in the values. > > *Approach 1*: attach a start time with every tuple. Note the end time for > that tuple in ack(). Calculate the time delta of start and end times. > > Latency value is ~ 104 ms. > > *Approach 2*: Using Storm UI parameter "complete Latency" to measure > latency. > > Latency value is ~ 2-3 ms. > > Could someone please explain why is there a huge difference in Latency > calculations? > If not on timestamp basis, how does storm internal metrics system > calculate the complete latency? > > Thanks, > Preethini >
