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From Keith Turner <>
Subject Re: cached connector
Date Fri, 26 Feb 2016 18:15:08 GMT
On Fri, Feb 26, 2016 at 11:56 AM, Josh Elser <> wrote:

> z11373 wrote:
>> My questions:
>> 1. Since I haven't killed that service instance yet, is it possible to
>> debug
>> and find out the culprit? 100x slower is too much. Is that expected? What
>> could be causing the slowness?
> No, definitely not expected.
> 2. This makes me think caching Accumulo connector may not be a good idea.
>> Current implementation is the cache got refreshed if there's exception.
>> Slow
>> read won't trigger exception, so it stays in the cache. Is it recommended
>> to
>> not caching the Accumulo connector?
> I don't think we have the means to tell you what went wrong, but perhaps
> we can help you find some clues. The Connector has some internal
> synchronization, but I would not have thought caching a Connector would
> have such negative impact -- sounds like a bug.
> * Try attaching a profiler to your service (e.g. Java Mission Control,
> YourKit). These can help you connect to your running service and figure out
> what is taking a long time.
> * You can also go the "low-tech" route and take a few stackdumps (e.g.
> `kill -3 <pid>` or `jstack`) on your service to see get an idea of where it
> is spending time.
> * Take a heap dump of the service (e.g. `jmap`). Perhaps there is a lot of
> garbage sitting on the heap not being collected or there's a memory leak.

There is also jstat, it can help you determine if the process is spending a
lot of time on GC.

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