[Mulgara-general] Spanning multiple disks

[Life is hard, and then you die]

On Mon, Jun 30, 2008 at 10:44:38AM -0500, Paul Gearon wrote:
> On Mon, Jun 30, 2008 at 10:28 AM, Chuck Borromeo <cborromeo3 at yahoo.com> wrote:
[snip]
> > I have a second question (and this is probably a simple one), how do I start Mulgara to use more java virtual memory?  I try running Mulgara from the command line with these parameters:
> >
> > java -Xmx1024m -jar mulgara-2.0-alpha.jar -p 4567

Unless you're doing explicit I/O (see below), you do _not_ want to
increase the heap size, as it just takes away memory that can
otherwise be used for mmap'ing the files. Mulgara's heap usage is
reasonably moderate, such that 128M should be sufficient and 256M is
more than enough.

> > I get java.IO.FileException: Cannot Allocate memory error at MappedIntFile.mapFile.  I have been trying to load a fairly large set of data into Mulgara and I get java heap memory errors.  I was hoping to extend the heap memory of Mulgara to avoid the errors while loading.   Any suggestions?
> 
> The issue here is that you are using the 32 bit JVM, and the system is
> hitting the 2GB limit with memory mapping.
> 
> There are 2 solutions, depending on your system.
> 
> If you have a 32 bit system, then you'll need to add the following to
> your command line:
>   java -Xmx1024m -Dmulgara.xa.forceIOType=explicit -jar
> mulgara-2.0-alpha.jar -p 4567
> 
> This will tell the system to NOT use memory mapping for the index
> files, meaning that that you can have greater than 2GB in these files.
> 
> If you have a 64 bit system, then just turn that option on:
>   java -d64 -Xmx1024m -jar mulgara-2.0-alpha.jar -p 4567

AFAIK the -d64 is only usable on Solaris; on Linux you get 32 or 64
bit depending on which jdk/jre you downloaded.


  Cheers,

  Ronald