Re: Next event size in a tree

Please do not submit your mails to two different places. I already answered your mail at the Forum. See: http://root.cern.ch/phpBB2/viewtopic.php?t=3251

Rene Brun

On Thu, 30 Mar
2006, Alessandro Thea wrote:

> Dear Rooters,
> I'm facing some memory problem due to some really _big_ events which came out
> from our simulation.
> After a quite large production we realized that some of this simulated events
> required ~1Gb of RAM just to be read from file.
> It turns out, from the event size returned by TTree::GetEntry() that only
> half of the memory is taken by the event.
> I suppose the rest is used in the reading operations (baskets? buffers?).
> I've also seen that the memory is released when the tree is deleted (and the
> file is closed?).
> Now is too late to re-organize the branches to reduce the memory usage, so I
> was wondering if there is a way to know
> in advance which is the size of the next event to be read to decide whether
> to skip it or not.
> Or if there is a way to force the tree to drop some meory after the event has
> been read. I tried with TTree::DropBaskets(), but it crashes during the next
> call of TTree::GetEntry().
> Thanks in advance for any suggestion,
> Alessandro
>
>
>
Received on Thu Mar 30 2006 - 11:58:33 MEST