[rules-users] memory issue when listening to market data

Mon Sep 29 14:57:37 EDT 2008

Ping,
I  think you should focus on the content of your heap and not on the  
specific size.

So here are my 0.02EUR:
1. get a working heap dump (google is your friend)
2. Inspect the heap (dont focus on measuring it too much)

#2 should give you an idea what is consuming the memory and thus  
should give you a starting point.

By the way: top reports the amount of memory the VM has allocated  and  
the amount of physical memory consumed.
Due to Java heap dynamics this is only somewhat coupled to the actual  
memory consumption of the VM.
But unless you start the VM with weird -X/-XX switches  the memory  
allocated / consumed should come down a while as the VM shrinks the  
heap.
So if it's not doing this the app is not releasing the objects.

This is probably an application and not a Drools issue.

-I

Am 29.09.2008 um 19:06 schrieb Cheng, Ping:

> Ingomar,
>
> I tried jmap -heap:format=b, but got some errors and jhat could not
> parse the dump file.
> Then I tried jmap -histo and I added up all objects' memory and it
> pretty much matched what I saw from jconsole.
>
> Is there any chance that jmap -histo and -heap return different  
> result?
>
> Thanks.
> -Ping
>
> -----Original Message-----
> From: rules-users-bounces at lists.jboss.org
> [mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Ingomar  
> Otter
> Sent: Monday, September 29, 2008 12:47 PM
> To: Rules Users List
> Subject: Re: [rules-users] memory issue when listening to market data
>
> Given the information remote diagnosis is not feasible.
> I would suggest to have a look at the heap ... to see where things are
> going.
> See
> http://weblogs.java.net/blog/kellyohair/archive/2005/09/heap_dump_snaps 
> .
> html
>
> --Ingomar
>
> Am 29.09.2008 um 17:30 schrieb Cheng, Ping:
>
>> All,
>>
>> I wrote a server which listens to the market data and generates  
>> alerts
>> based on some conditions.
>> It listens to about 300 symbols and contains  30 simple rules. It
>> works
>> fine when the market is quiet. It uses about 500 M in memory and  
>> there
>> is no big difference between reports from top and jconsole.  When
>> market
>> is busy, memory displayed in jconsole is still ok, but top reports
>> much
>> more memory and it did not come down at all. Sometimes it could reach
>> 50G when it's a crazy day.
>>
>> I used jmap to check the memory map  and it looks fine from java
>> view, I
>> wonder if drools hold something when it's very busy? What is
>> supposed to
>> happen if drools could not handle the work load?
>>
>> Thanks for your help.
>>
>> -Ping
>>
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