Hi HP, For sure, this model must be very slow! You should be able to gain at least a factor 20. you import the full data in memory. I suggest a first trivial step that requires a minimal change in your program. Change the buffer size from 32000 to 2000. I expect a gain in time between 2 and 3 with this simple modification. Give me the result with and without compression. I will tell you more how to gain a bigger factor once I have the result of this first test. Rene Brun On Fri, 22 Nov 2002, HP Wei wrote: > root [3] IBM.Print() > ****************************************************************************** > *Tree :IBM : * > *Entries : 2369 : Total = 36708 bytes File Size = 36708 * > * : : Tree compression factor = 1.00 * > ****************************************************************************** > *Br 0 :Date : Date/I * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 1 :Time : Time/I * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 2 :Bid : Bid/D * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 3 :Ask : Ask/D * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 4 :Price : Price/D * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 5 :Bidsize : Bidsize/I * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 6 :Asksize : Asksize/I * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 7 :Size : Size/I * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 8 :Upsize : Upsize/I * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 9 :Upstate : Upstate/b * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 10 :HighSoFar : HighSoFar/D * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 11 :LowSoFar : LowSoFar/D * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > *Br 12 :Vwap : Vwap/D * > *Entries : 2369 : Total Size= 0 bytes File Size = 0 * > *Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 * > *............................................................................* > > ** when the root_file was generated, > I use all default settings for TFile(). > So the buffer size is the default 32000. > > btw, the version of ROOT I am using is 3.01/00 > running on Sun Solaris. > > --HP >
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