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From Tim Bain <tb...@alumni.duke.edu>
Subject Re: Out of memory exception
Date Fri, 06 Apr 2018 13:14:10 GMT
Sorry, I quoted you as saying "unresponsive" but your actual word was
"hung."

On Fri, Apr 6, 2018, 7:13 AM Tim Bain <tbain@alumni.duke.edu> wrote:

> 1GB sounds a little small for that volume, especially if there is any
> danger of some consumers of durable topics being offline for a while, or of
> all consumers on a given queue being offline. Either way, you've proven
> that 1GB isn't enough, by hitting an OOM. The fact that you haven't hit it
> till now probably means you could get away with using 2GB, but if your host
> has the memory available, I'm never going to argue against using it.
>
> In your test environment, I'm confused about how you can limit the JVM to
> 4GB of heap, and then have it take 5GB. Unless the 5GB number is total
> memory as measured by something like top? If so, that just means that the
> JVM made the heap 4GB, but it doesn't mean that there's actually 4GB of
> data in it. Too can't tell you that, so you'd want to use JConsole or
> JVisualVM to get an understanding of how much heap is actually used and how
> much time is being spent GCing.
>
> Also, can you more clearly describe what you mean by "unresponsive"?
>
> Tim
>
> On Fri, Apr 6, 2018, 12:22 AM Lionel van den Berg <lionelv@gmail.com>
> wrote:
>
>> Hi,
>>
>> We're still investigating, turning up logging etc. but we've come across
>> two issues:
>>
>> 1. At our site deployment with default memory usage (1gb) AMQ threw an
>> out of memory exception. We couldn't determine exactly why, whether it was
>> cumulative memory use of a peak memory use. We have around 50 connections
>> and perhaps a few thousand topics with quite a lot of data, perhaps
>> 4GB/hour going in and 15 x that much going out.
>>
>> 2. In our lab we increased memory available to 4Gb by modifying env (see
>> attached) and turn up logging (also see attached), within about 5 hours AMQ
>> had reach 5Gb and hung without an exception. Unfortunately the system
>> wasn't being monitored and apparently the logs weren't any good because
>> they'd rolled over too many times.
>>
>> I realise the information is a little vague at this stage so I'm only
>> looking for pointers on where to look.
>>
>

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