TChain: TBufferFile::WriteByteCount>: bytecount too large

[ramkrishna]

Dear experts,

I am getting the issue with the byte count too large. I checked there there are several post there on the ROOT forum like here. But, I am unable to get why I am getting this.

I am trying to add 4 files in a TChain like below (taken from my full macro here):

def reduceTree(inTree, cut):
  small = inTree.CopyTree(str(cut))
  return small

treeNames = [
  "DiPhotonJetsBox_MGG-80toInf_13TeV.root/DiPhotonJetsBox_MGG_80toInf_13TeV_Sherpa_13TeV_HHWWggTag_1",
  "datadrivenQCD_v2.root/Data_13TeV_HHWWggTag_1",
  "TTGG_0Jets_TuneCP5_13TeV.root/TTGG_0Jets_TuneCP5_13TeV_amcatnlo_madspin_pythia8_13TeV_HHWWggTag_1",
  "TTGJets_TuneCP5_13TeV.root/TTGJets_TuneCP5_13TeV_amcatnloFXFX_madspin_pythia8_13TeV_HHWWggTag_1"
 ]
histo_scale.Reset()
bkg_tree_2017 = ROOT.TChain()
for tree in treeNames:
   bkg_tree_2017.AddFile(inDir+'/'+tree)
bkg_tree_2017 = reduceTree(bkg_tree_2017,Cut_noMass)

sum of size of these 4 files is 711M. I am not sure why I am getting this error. If I run my macro with individual files or 2 at at time it works fine but not with all of them simultaneously.

Do you have any suggestion how I can fix this.

Thanks in advance for your help.

with regards,
Ram

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ROOT Version: 6.20/07
Platform: lxplus
Compiler: Not Provided

---

[Wile_E_Coyote]

Try:

file = ROOT.TFile('bkg_tree_2017.small.root', 'recreate')
bkg_tree_2017 = reduceTree(bkg_tree_2017, Cut_noMass)
file.Write # ... or ... bkg_tree_2017.Write()