Re: I'm new to prevayler: will Prevayler ever be able to share an object across 2 or more computers?

If you just run a little over your limit, you will be saved by the
magic of virtual memory.   Almost all operating systems today will
store parts of your data on the disk.  They try to predict which parts
are not being used and save it to disk, allowing you to run programs
bigger them memory.  This usually works OK if you are just a little
over your limit, but disk is much slower than memory so as it stores
more and more on disk, your performance gets worse and worse.  But it
allows your program to keep working while you are waiting to install
the new memory.

Twenty years ago I worked with a virtual memory system that would
allow you to store part of your data in the memory of another
computer, not just on the disk.   I don't know of any modern operating
systems that allow you to do this, but maybe they do.  The performance
really isn't that great; the network is just as slow as the disk.

If you want good performance, you need to partition your application
so that some of the objects are in one Prevayler image and the others
are in another.   This is a lot of work.  But you would get much
better performance doing this than you would just sharing memory over
the network.

Virtual memory works, and gives you the time you need to make a memory
upgrade, which is the real solution.

-Ralph Johnson

On Wed, Oct 12, 2011 at 7:28 AM, Naveen Chawla <[email protected]> wrote:
> This may be a stupid question, but - Say I'm close to running out of
> memory... I'll have to shut down the computer and install more memory
> modules, right?
>
> So I thought of a dream feature - having no knowledge about how Prevayler
> (or even Java) really works on the inside - which is just to plug in one or
> more other computers while the first one is still on - and Prevayler
> automatically starts "sharing" the object if memory is running low, treating
> it as one object, so you never run out of memory and you never have to
> switch off your computers.
>
> This may sound really wacky, but will this ever be possible with Prevayler?
>
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> definitive record of customers, application performance, security
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> sense of it. Business sense. IT sense. Common sense.
> http://p.sf.net/sfu/splunk-d2d-oct
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------------------------------------------------------------------------------
All the data continuously generated in your IT infrastructure contains a
definitive record of customers, application performance, security
threats, fraudulent activity and more. Splunk takes this data and makes
sense of it. Business sense. IT sense. Common sense.
http://p.sf.net/sfu/splunk-d2d-oct
_______________________________________________
To unsubscribe go to the end of this page: http://lists.sourceforge.net/lists/listinfo/prevayler-discussion
_______________________________________________
"Databases in Memoriam" -- http://www.prevayler.org