Problems with large ROOT files?

Hi Root Talkers,

For reasons that are irrelevant to this question I have managed to produce a ROOT file with two TTrees, with a file size of 7.1 GB! Should I expect any problems from dealing with ROOT files of this size? The file opens without a hassle and I seem to be able to read all the data from the TTrees. My impression from reading through related posts on this forum is that there is no real danger in big root files. Is this right?



Indeed ROOT should have no problem dealing with a file this size (or any size that can be described by a 64 bit integer for that matter).


I am wondering what is the earliest ROOT version which should not have such a file-size problem? Or any version of ROOT doesn’t have such a problem? The Fermilab D0 framework root version is: v4_04_02b_fbits_trefarray7_eh-GCC_3_4_3-opt. Due to my experience, this version is affected.

Files bigger than 2 Gigabytes are supported since ROOT version 4.00.

Trees bigger than 2 Gigabytes are supported since version 4.02/00