Re: [ROOT] Multiple access to a file

From: Rene Brun (Rene.Brun@cern.ch)
Date: Fri Apr 26 2002 - 09:30:28 MEST


Since the beginning of the ROOT project, we have deliberatly rejected
the option of concurrent writers in the same Root file.
You can ,however, do this with multiple writers communicating
via sockets with a central writer.
When concurrent write is required, we recommend an hybrid model
using Root for the event data storage and an RDBMS (MySQL, Oracle, etc)
for meta data like run/file catalogs.

Rene Brun

Veysi E. Ozcan wrote:
> 
> Hi ROOTers,
> 
> I have a simple question. I want to run multiple different proccesses that
> use ROOT 2.25-03 (yes I know it is ultra old) libraries, and these
> processes will write into one single ROOT file at the same time. There are
> subdirectories in the file and the processes just write into histos in
> their respective subdirectories. Is this possible? Is this dangerous? If
> so, why?
> 
> Thanks for all the help. If the answer turns out to be complicated, you
> can point me to any other source as well.
> 
> Cheers,
> Veysi Erkcan Ozcan
> Stanford University



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