[talk] Python

Edward Capriolo edlinuxguru at gmail.com
Wed Apr 27 18:35:54 EDT 2016


Correct. The Java garbage collections use system threads to navigate mark
the objects in the heap. If you can not finish the sweep fast enough you
get a pause.

I never set a JVM higher than 12 GB heap.

If you really need large off heap structures you can use one of several off
heap libraries http://www.mapdb.org/.

Anecdotal. Keep in mind I have tested this and you can create 'a lot more
objects' given the same RAM than many other popular non java languages. :)

On Wed, Apr 27, 2016 at 4:13 PM, Pete Wright <pete at nomadlogic.org> wrote:

>
>
> On 04/26/2016 03:56 AM, Brian Coca wrote:
>
>> As many a Java dev has told me: "the only problem is that you did not
>> install enough RAM, just add it, it's cheap!"
>>
>>
>>
> and therein is the issue - in practice i've found that by adding more
> memory to a JVM heap will tend to worsen GC pauses, especially for latency
> sensitive operations.  then you get to do all sorts of fun stuff like
> storing cached objects outside of the JVM or lord knows what.
>
> i spent about 3 months trying to help a team tune their java app when they
> noticed it would periodically show latencies of several seconds. they kept
> adding more memory to the heap, which made things worse.  once we turned on
> debugging metrics for GC it became painfully apparent that due to the huge
> heap that they had allocated GC was taking ages to complete and stopping to
> world in the process.  good times :)
>
> -pete
>
> --
> Pete Wright
> pete at nomadlogic.org
>
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