disk resident Ntuples, memory, etc....

From: GALYARDT@acdft1.fnal.gov
Date: Tue Jul 07 1998 - 16:52:23 MEST


Hello,

When I declared the Ntuple, at first I used the default buffer size (which , now
that I think about it must be 32000 _bytes_).  After getting the error in the
"new" operator (out of memory), I cut the buffer to 16000 bytes.  All of my
"new" operators have "delete"'s, but I'm still using a lot of system resources. 
I cut the buffer size again to 1600, and it seems to recover with no errors, but
the system is extremely sluggish afterword.  Also, I only count ~30 events
(which are printed to the screen before they're input to the Ntuple), when I
should be getting exactly what I asked for, 100.  Here is the result of the
ntuple->Print() command Rene asked for:

******************************************************************************
*Tree    :ntuple    : SVX3C DATA                                             *
*Entries :        0 : Total  Size =         0 bytes  File  Size =          0 *
*        :          : Tree compression factor =   1.00                       *
******************************************************************************
*Branch  :c000      : c000                                                   *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 *
*Baskets :        0 : Basket Size =      1600 bytes  Compression=   1.00     *
*............................................................................*
*Branch  :c001      : c001                                                   *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 *
*Baskets :        0 : Basket Size =      1600 bytes  Compression=   1.00     *
*............................................................................*
*Branch  :c002      : c002                                                   *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 *
*Baskets :        0 : Basket Size =      1600 bytes  Compression=   1.00     *
*............................................................................*
*Branch  :c003      : c003                                                   *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 *
*Baskets :        0 : Basket Size =      1600 bytes  Compression=   1.00     *
*............................................................................*
*Branch  :c004      : c004                                                   *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 *
*Baskets :        0 : Basket Size =      1600 bytes  Compression=   1.00     *


--- It continues identically to this for all 128 variables (c000 -- c127).

Thanks for the help,

Jason Galyardt



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