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From "Dale, Matt" <Matt.D...@beCogent.com>
Subject RE: [OT] - JVM Max Heap Size on Linux
Date Sun, 15 Aug 2004 09:24:02 GMT
Interesting idea and if it was my own code i'd certainly consider this. Although if it was
my own code I don't think i'd let the sessions get so big in the first place. Unfortunately
its now our code so we're stuck with what has been supplied.

Ta
Matt

-----Original Message-----
From: Wade Chandler [mailto:wchandler@redesetgrow.com]
Sent: 14 August 2004 23:38
To: Tomcat Users List
Subject: Re: [OT] - JVM Max Heap Size on Linux


Dale, Matt wrote:

> Hi,
> 
> Has anyone got around the maximum heap size of 2G on linux? We've got a 
> new server with 12G of ram which was going to be used for an uber tomcat 
> but this plan may have to be changed if we can't get more than 2G of 
> memory used for the JVM.
> 
> Ta
> Matt
> 
> 
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You could write some native code and use the apache apr package or 
something similar to create shared memory or memory mapped files.  Then 
use the object you wrap around this code and store it in your session.

This way you can have as much memory as you want stored in these 
objects.  Pull the memory from the mapped file only as you use it to 
keep from expanding it all back into the jvm process memory at one time. 
  The speed difference will probably not be noticeable if you have a 
good search algorithm setup.

That or you could tie your session information to a database and do the 
same thing you would do with the mapped memory.  The session would 
simply hold the id for the db session table.  Though this may be a bit 
slower.

Don't know if that would be possible for you or not.

Wade


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