Merging with 'hadd' results in 'std::bad_alloc'

From: Ida Häggström <ida.haggstrom_at_radfys.umu.se>
Date: Tue, 11 Oct 2011 15:21:11 +0200

Hello!

I'll start with some info:
Root version: 5.28/00a (21 February 2011) OS: Ubuntu version 10.10 (as a guest via VirtualBox4.0.4 on host Windows 7) Memory: 10082 MB base memory, 6 processors allocated by VirtualBox (total 16384 MB, 8 processors on machine).

I'm experiencing some problems when trying to merge some root files. I have six files (around 1.1 GB each) that I want to merge. The files contain the same structure (four different trees + some histograms each). I'm trying to use the 'hadd' method, but after a couple of hours it crashes with the message "terminate called after throwing an instance of 'std::bad_alloc'" (see below).
I've googled the issue and figured I run out of memory (I'm not so skilled with root or C++!).

I found a thread addressing a similar issue as mine ( http://root.cern.ch/phpBB3/viewtopic.php?t=9008) where it was suggested to flush the baskets of each root file, then use hadd. I've tried this according to:

   TFile f(fileName.c_str(),"update");
   TTree *T1 = (TTree*)f.Get("finalCoinci");    T1->FlushBaskets();
   T1->Write();

on all trees of every root-file, but I still get the same error. Can anyone help me with some ideas?
Thanks!
Ida

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hadd test.root rootOutput*
Target file: test.root

Source file 1: rootOutput_Prompts_t0-1.root
Source file 2: rootOutput_Prompts_t0-2.root
Source file 3: rootOutput_Prompts_t0-3.root
Source file 4: rootOutput_Prompts_t0-4.root
Source file 5: rootOutput_Prompts_t0-5.root
Source file 6: rootOutput_Prompts_t0-6.root

Target path: test.root:/

rootOutput_Prompts_t0-1.root tree:finalCoinci entries=1234567890
rootOutput_Prompts_t0-2.root tree:finalCoinci entries=1234567890
rootOutput_Prompts_t0-3.root tree:finalCoinci entries=1234567890
rootOutput_Prompts_t0-4.root tree:finalCoinci entries=1234567890
rootOutput_Prompts_t0-5.root tree:finalCoinci entries=1234567890
rootOutput_Prompts_t0-6.root tree:finalCoinci entries=1234567890

terminate called after throwing an instance of 'std::bad_alloc'   what(): std::bad_alloc
Aborted

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Received on Tue Oct 11 2011 - 15:21:18 CEST