Re: Unexpected TTree cycle numbers

Hi Brett,

When AutoSave is called, the current buffers are flushed and the current version of the TTree header written to the file. I am not sure what you mean by "Both trees hold identical data". The Tree header contains only the metadata describing the Tree, not the data itself. If your Tree headers are identical, it means that you save it twice. A typical scenario reproducing this case is when doing

    tree.Write()
    file.Write()

Rene Brun

Brett Viren wrote:
> Hi Rene,
>
> Rene Brun <Rene.Brun_at_cern.ch> writes:
>
>
>> see TTree::AutoSave
>>
>
> Thanks, this looks like it may be implicated in what I see as the higher
> cycles only occur in the largest TTree and only after a sufficiently
> large number of events have been run.
>
> Let me ask another question. When I open the file in a TBrowser I see
> two copies of my tree (with cycle numbers ";3" and ";4"). Both trees
> hold identical data. The AutoSave documentation says:
>
> Once the key with the tree header has been written, the previous cycle
> (if any) is deleted.
>
> This seems to say I should not see two trees. Any ideas as to what
> might be keeping the older ";3" cycle around?
>
> BTW, this is with ROOT 5.22.00a.
>
> Thanks,
> -Brett.
>
Received on Tue Apr 27 2010 - 09:35:55 CEST