Re: [ROOT] slow reading files

From: Matthew D. Langston (langston@SLAC.stanford.edu)
Date: Tue Sep 26 2000 - 18:01:57 MEST

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In reply to: Haitao Liu: "[ROOT] slow reading files"
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Hi Haitao,

I uncovered a ROOT bug in 2.25.03 when TChain::Process processes a user
defined TSelector  (see
http://root.cern.ch/root/roottalk/roottalk00/2583.html).  One of the
symptoms of the bug was that TFile I/O slowed to a crawl.  You didn't give
enough details in your email to really understand what was causing your
problem.  If you are you using TChains and TSelectors, then you may have run
into the same problem that I did.

Regards, Matt

----- Original Message -----
From: "Haitao Liu" <liuht@particle.phys.ethz.ch>
To: <roottalk@pcroot.cern.ch>
Sent: Tuesday, September 26, 2000 7:52 AM
Subject: [ROOT] slow reading files


> Dear rooters,
>
> I am quite confused now. It takes me  hours to read a small root file,
only
> 4MegaByte, it does not issue any warning.
> I can process ten GigaBytes data in root files on the same machine in the
> same time.
> So, what going wrong, I use the latest version 2.25/03
>
> With regards                                 Haitao
>

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