maximum number of fills in TH3 ?

Dear rooters,

  I am experiencing a problem with the TH3 class. I have written a simple Monte-Carlo to investigate the PID capabilities of our detector. It takes few hours to process the simulated events, but because I do not need the full information, I prefer to generate a TH3 and not a tree. I am experiencing a memory leak with root when I try to open the file containing the generated TH3 histograms and plot them (essentially root tries to use all the available memory on the machine up to 7-8 GB).

  In the beginning I thought it was connected to the number of channels and so I reduced the dimensions to 100*100*100 channels. The problem remained.

  I noticed that everything works well if I use a reduced statistics (1/10). So I started to experiment with the TH3 class and I believe I found a problem when a channel is filled more than 2**31 times. I tried to use a TH1 and it works without problems. I attach a small simple macro I used to do my checks. I have used root 5.22 and 5.26, both have the problem. (Note that the file is written, root only stalls after).

  Is this a known limitation ? Can it be removed or avoided somehow? If not, the limit is in the number of fills for a single channel or for all the histogram (then I could add a check in my program)?

Thank you for any assistance,
Alessio Mangiarotti.