Re: Recovering badly closed file?

Hi Bret,

Do you get the same error with 'BeamMon;2161' (which is a priori newer than ;1) ?

Cheers,
Philippe.

Brett Viren wrote:
> Hi RootTalk,
>
> I have a data file that is corrupted. This probably occurred due to an
> unclean shutdown of the process writing the file. Is there a way to
> recover any of the data?
>
> Here is what I have tried:
>
> I can open it with our ROOT based application ("loon" = ROOT + our
> libraries and data dictionaries). I then create a TFile object with it
> and call TFile::Recover(). This gives me:
>
>
> ----------------------------------------------------------------------
> loon [0] TFile* f = new TFile("/home/bviren/B100112_080001.mbeam.root")
> loon [1] f->Recover()
> Info in <TFile::Recover>: /home/bviren/B100112_080001.mbeam.root, recovered key TTree:BeamMon at address 167327993
> (Int_t)(1)
> loon [2] f->ls()
> TFile** /home/bviren/B100112_080001.mbeam.root Persistency file
> TFile* /home/bviren/B100112_080001.mbeam.root Persistency file
> KEY: TTree BeamMon;1 Persistency stream tree
> KEY: TTree BeamMon;2161 Persistency stream tree
> ----------------------------------------------------------------------
>
>
> Recover() produced tree "BeamMon;1". Using a TBrowser to browse either
> of these trees give errors of the type:
>
>
> ----------------------------------------------------------------------
> Error in <TExMap::Remove>: key 256 not found at 257
> Warning in <TBufferFile::CheckObject>: reference to object of unavailable class TObject, offset=256 pointer will be 0
> Error in <TExMap::Remove>: key 1356857360 not found at 274
> Warning in <TBufferFile::CheckObject>: reference to object of unavailable class TObject, offset=1356857360 pointer will be 0
> Error in <TExMap::Remove>: key 64 not found at 65
> ...[snip]
> Error in <TExMap::Remove>: key 65536000 not found at 131
> Warning in <TBufferFile::CheckObject>: reference to object of unavailable class TObject, offset=65536000 pointer will be 0
> Error in <TExMap::Remove>: key 1708311296 not found at 62
> Warning in <TBufferFile::CheckObject>: reference to unavailable class TObject, pointers of this type will be 0
> Error in <TBufferFile::CheckByteCount>: Byte count probably corrupted around buffer position 282800:
> 603979859 for a possible maximum of 108
> Error in <TBufferFile::CheckByteCount>: object of class TObjArray read too many bytes: 21 instead of -1471902456
> Warning in <TBufferFile::CheckByteCount>: TObjArray::Streamer() not in sync with data on file /home/bviren/B100112_080001.mbeam.root, fix Streamer()
> Error in <TBufferFile::CheckByteCount>: Byte count probably corrupted around buffer position 282920:
> -1471902456 for a possible maximum of -29
> Error in <TBufferFile::CheckByteCount>: object of class TBranch read too many bytes: 282626 instead of 282487
> Warning in <TBufferFile::CheckByteCount>: TBranch::Streamer() not in sync with data on file /home/bviren/B100112_080001.mbeam.root, fix Streamer()
> Error in <TClass::New>: cannot create object of class TIter
> Segmentation fault
> ----------------------------------------------------------------------
>
>
> If it is of any use, the file is here (160 MB):
>
> http://www.phy.bnl.gov/~bviren/root/corrupt-file/B100112_080001.mbeam.root
>
>
> Thanks for any help!
> -Brett.
>
>
Received on Wed Jan 20 2010 - 22:26:06 CET