Histograms with huge entries seems to be empty!

_ROOT Version: 5.34.36
_Platform: CentOS7
_Compiler: g++


I have a huge root files (in total 160 GB) containing the same informations. These files are used in a TChain to get the tree. The total entries are more than 1 800 000 000.

The problem is, when I fill TH1D histograms with these entries, I get empty histograms, while when I use half of the files I get the right results.

Can someone help in this issue.

Hi @mbouta ,
and welcome to the ROOT forum!

v5.34 is very old, could you verify whether the same problem exists in v6.24/06. If the problem is still present, can you please provide a minimal reproducer so we can check what’s going on?


Dear @eguiraud,
Thank you for your hospitality and for your replay.

For the time being I can’t change the root version since several jobs would be affected.

I will try leter and keep you informed.


“How” do you fill the histogram?

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