[R] Suspected memory leak with R v.2.5.x and large matrices with dimnames set

Peter Waltman waltman at cs.nyu.edu
Sat Aug 18 23:13:46 CEST 2007

Hi Seth -

Thanks for the follow up.  I'll definitely check out the devel version 
at some point since while I've come up with a workaround, this is 
causing problems for me as it uses up so much memory on some systems 
that R starts throwing malloc errors and has to be killed from the 
command line.  The machine I'm thinking of in particular is a MacOS 
machine with 8 gigs of memory.

Also, having the row and column names set to alphanumeric names causes 
the processing to slow down significantly - as much as by a power of 10 
(or more).

As for you speculation that the memory released by R may not be 
recognized as being free'd by the OS, as a further test, I re-ran my 
code snippet three consecutive times w/in the same R interpreter 
window.  In theory, if there were a memory leak, after the first run 
(resulting in a memory stamp of 2 gig), the subsequent runs would 
further increase R's memory stamp, i.e. up to 4 after the second, and 6 
for the 3rd.

This didn't happen, and R's stamp remained at 2 gig, so I can only 
assume that you're correct and I was wrong about a leak. 

Still, it's quite the memory hog when using dimnames, so I'll have to 
avoid those for now and will try the devel version you mentioned.

Thanks and have a good weekend,


Seth Falcon wrote:
> Hi Peter,
> Peter Waltman <waltman at cs.nyu.edu> writes:
>>    Admittedly,  this  may  not be the most sophisticated memory profiling
>>    performed,  but  when using unix's top command, I'm noticing a notable
>>    memory leak when using R with a large matrix that has dimnames
>>    set.
> I'm not sure I understand what you are reporting.  One thing to keep
> in mind is that how memory released by R is handled is OS dependent
> and one will often observe that after R frees some memory, the OS does
> not report that amount as now free.
> Is what you are observing preventing you from getting things done, or
> just a concern that there is a leak that needs fixing?  It is worth
> noting that the internal handling of character vectors has changed in
> R-devel and so IMO testing there would make sense before persuing this
> further, I suspect your results will be different.
> + seth

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