[R] R memory usage and size limits

[Prof Brian Ripley]

Please read ?"Memory-limits" and the R-admin manual for basic 
information.

On Thu, 5 Feb 2009, Tom Quarendon wrote:

> I have a general question about R's usage or memory and what limits exist on 
> the size of datasets it can deal with.
> My understanding was that all object in a session are held in memory. This 
> implies that you're limited in the size of datasets that you can process by 
> the amount of memory you've got access to (be it physical or paging). Is this 
> true? Or does R store objects on disk and page them in as parts are needed in 
> the way that SAS does?

That's rather a false dichotomy: paging uses the disk, so the 
distinction is if R implemented its own virtual memory system or uses 
the OS's one (the latter).

There are also interfaces to DBMSs for use with large datasets: see 
the R-data manual and also look at the package list in the FAQ.

> Are there 64 bit versions of R that can therefore deal with much larger 
> objects?

Yes, there have been 64-bit versions of R for many years, and they are 
in routine use on very large problems.


> Many thanks.
>
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>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595