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From jmmec <jmmec2...@gmail.com>
Subject Re: ZK 3.4.5: Very Strange Write Latency Problem?
Date Fri, 21 Feb 2014 01:50:40 GMT
I should also mention:

During the 20 minute test run, I confirmed that NOTHING was written to the
"zookeeper.out" file.  So snapshots weren't written, and nothing else was
written, nothing at all.  It was a very clean run.


On Thu, Feb 20, 2014 at 7:44 PM, jmmec <jmmec2009@gmail.com> wrote:

> Hi everyone,
> I'm new to the list and especially ZooKeeper.  I'm exploring ZK 3.4.5 with
> a dummy application (hacked up & simple) that is using the C API with async
> calls.   It creates 100,000 znodes, slowly, where each znode has 133 bytes
> of data.  Simple.  :)
> Although my tool creates znodes slowly (about 84 per second) and CPU / RAM
> / Network / etc is not at all stressed, I am seeing periodically very long
> "write" latency times (76ms+) reported by ZooKeeper.  My independent
> analysis confirms what ZooKeeper is reporting.  Wow.
> The one-page PDF file below explains the problem in more detail and
> includes a chart that shows the periodic write latency delays:
> https://docs.google.com/file/d/0Bww02z29xbYyUFEtbXQzOG9GVDA/edit?usp=sharing&pli=1
> I don't know much about JAVA and haven't started poking into ZooKeeper,
> but since ZooKeeper is reporting the latency, then it seems to be coming
> from ZooKeeper itself.
> Any idea what might be causing this, or how better to diagnose what might
> be happening?
> Thanks so much!

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