Re: [ROOT] Estimation of the size of a tree object in memory

From: Rene Brun (Rene.Brun@cern.ch)
Date: Sat Dec 14 2002 - 16:31:38 MET


Hi HP,

Please read the Users Guide about monitoring object statistics in memory.



On Fri, 13 Dec 2002, HP Wei wrote:

> 
> Hi rooters,
>   If we get a tree object into the memory,
>   how much memory does it occupy ??

A tree in memory requires the space for teh Tree header itself (class
TTree) + the branch definitions (classes TBranch, TBranchElement)
and one buffer per branch.

> 
>   How about one tree with, say five branches activated ??
>   (Assume the buffer_size for one branch is 1Kbytes.)
> 
>   Is there a difference in memory usage between
>   (1) one tree with 100 branches activated,
>   and
>   (2) 20 trees with 5 branches for each tree ?
> 

should be about the same

Rene Brun

>   If these are hard to know, just a rough
estimate will
>   be fine.
> 
> Thanks,
> HP
> 
> 
> 



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