Adding many root-files to one

ROOT
1

Dear Rootes,

I have the following problem (macro attached). When trying to add many files (approx. 2000) with my macro I receive the following error message:

SysError in TFile::TFile: file File_156.root can not be opened for reading (Too many open files)
SysError in TFile::TFile: file File_157.root can not be opened for reading (Too many open files)
aso

Is there a better way to solve this problem? Thanks a lot in advance.

Best regards,

Michael
MergeFiles.C (1.58 KB)

2

Hi,

The operating has a limit (cutomizable) of the number of files you can open at the same time. To work around the issue, you are going to have to merge fewer files at a time.

Cheers,
Philippe.

3

Hi Philipp,

Thanks a lot for your answer.

Is there no easier way or a workaround for that instead adding first a small bunch and then add the fewer ones together?

Thanks.

Cheers,

Michael

4

Hi Michael,

Unfortunately, this currently the only solution (If you happen to improve TFileMerger to support this case, we will be happy to incorporate your patch :slight_smile: ).

Cheers,
Philippe.

5

Hi Philippe,

Let’s see maybe I will find a workaround.

Cheers,

Michael