Re: a problem with TTreeCache

From: Szymon Gadomski <szymon.gadomski_at_cern.ch>
Date: Mon, 6 Feb 2012 09:26:16 +0100


Thank you Philippe. We will be following the ROOT forum entry with great interest. The users of our DPM, at the Uni of Geneva, are working without the cache, which slows down the processing.

If we could setup a test, which would help you diagnose the problem, please let us know.
Best wishes
Simon

On 3/2/12 6:45 PM, Philippe Canal wrote:
> Hi Simon,
>
> See the similar report on the ROOT forum
> at <http://root.cern.ch/phpBB3/viewtopic.php?t=14082>
> for further update.
>
> Cheers,
> Philippe.
>
>
> On 1/18/12 10:58 AM, Szymon Gadomski wrote:
>> Dear ROOT Developers,
>> While reading data from our DPM Storage Element, using the
>> rfio protocol, we have seen errors that seem to come from
>> TTreeCache. Here is a report.
>>
>> The error message is:
>>
>> Error in <TRFIOFile::TRFIOFile>: error doing rfio_read
>> Error in <TBranch::GetBasket>: File:
>> rfio:///dpm/unige.ch/home/atlas/atlaslocalgroupdisk/user/wbell/data11_7TeV/user.wbell.data11_7TeV.00191239.physics_Muons.merge.NTUP_TOPMU.f413_m1019_p694_p722_thin0001_0001.111112032448/user.wbell.005705._00037.output.root
>> at byte:536958, branch:EF_e45_medium1, entry:459, badread=1,
>> nerrors=1, basketnumber=1
>> terminate called after throwing an instance of 'std::out_of_range'
>> what(): vector::_M_range_check
>> /var/spool/torque/mom_priv/jobs/1418590.grid07.unige.ch.SC: line 55:
>> 6815 Aborted
>>
>> This happens when the Storage Element is busy. An 'error doing
>> rfio_read' leads to 'std::out_of_range'. It looks like reading
>> is not blocked when the process should be waiting for more data.
>> Instead the process continues and crashes, printing errors due
>> to corrupted data.
>>
>> In the user code we have the lines (m_tree is a TTree*):
>>
>> m_tree->SetCacheSize(104857600);
>> TTreeCache::SetLearnEntries(1); // Stop learning after 1 entry is read.
>> m_tree->AddBranchToCache(branchName,true);
>>
>> Removing all these lines makes the errors disappear.
>> This is why we think there is a problem with the TTreeCache.
>> We are using ROOT 5.30/05.
>>
>> Please let us know if any more information would be useful.
>> Best regards,
>> Szymon Gadomski
>>

-- 
==================================================
Szymon GADOMSKI
Université de Genève, Section de physique
Département de physique nucléaire et corpusculaire
24, Quai Ernest-Ansermet, CH-1211 Genève 4

phone ++41 22 767 7935 (CERN)
or    ++41 22 379 6278 (DPNC)
==================================================
Received on Mon Feb 06 2012 - 09:26:25 CET

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