Odd behaviour when using several TCuts


I noticed a quite odd behaviour in ROOT (5.13) when I use some TCut objects.
Everything goes well when I plot something from my ntuple using three TCut objects. But when I try to add another cut (as its own TCut as well as simply attaching >&&“cut-params”< to the other cuts) and plot it anew, ROOT returns

Error in <TBasket>: fNbytes = 6341, fKeylen = 77, fObjlen = 7920, noutot = 0, nout=0, nin=6264, nbuf=7920 file probably overwritten: stopping reporting error messages Error in <TBranch>: File:...

  • and sometimes with some unzip error -
    Strangely enough when I plot the variables used fit parameters no error appears (as well when using the fit parameters “raw” in Draw() ). Also I can use problematic fourth TCut with any two the other three cuts and nothing happens but not with all three?!

Is there some limitation of the number of TCut cuts?

Cheers & Thanks for any idea,

This sounds like it is related in a bug with the new prefetch cache. This bug has been fixed. A work-around is to disable the cache:



Hi Phillippe,

thanks for your answer.
Do you know in which version is this bug fixed? (I use ROOT V5.13).


This problem was fixed on October 19 at 21h42. see:
It is not part of 5.13/04. You must use the CVS head
or wait November 22 for the release of 5.13/06


Just wanted to add that this exhibits more than just error message type behaviour. I was getting constant segmentation faults when drawing histograms with large numbers of cuts.

The SetCacheSize(0) workaround has fixed all the problems for the present, however.