When I try to merge root files with the same structure using $ROOTSYS/bin/hadd I get the following response:
hadd Opening the next 77 files. No idea what does it mean. But the size of merged file is less than I would expect. Therefore I suspect that not all files are merged. Using ROOT 6.06/00.
How many files are you trying to merge?
Does it work if you merge 2 or a small number of files?
On what is your expected merged file size based?
I encountered it first when I tried to merge 1000 files.
With the file size everything seems to be ok, after I have checked the average number of events per file.
That means all files were merged.
Still puzzled what means 77 files.
So, if I understand correctly, the result is not anymore wrong or unexpected.
The only problem is the message, which is a verbosity message normally printed if you run hadd in verbose mode, i.e. with the switch ‘-v [verbosity]’: is this your case?
Yes the result seems to be as expected.
I do not run hadd with the switch -v but simply like hadd outputfile inputfiles.
Ok, good to read that the result is ok.
The verbosity is actually on by default, so the message is normal when merging a large number of files.
Passing ‘-v 0’ should silence it.