Re: is TTreeSQL dumping the whole table ?

From: Tristan Beau <beau_at_in2p3.fr>
Date: Thu, 2 Feb 2006 09:18:07 +0100

Hi,

   I tried the latest version of ROOT (I got it from the CVS repository), version 5.09/01 16 December 2005, compiled with gcc 3.4.3.

   The TTreeSQL constructor works on the machine used (the first test with root 5.08.00 was on my laptop), but it takes a lot of time and requires a lot of network data transfer.

   Then, I tried some plots with some t->Draw("onefield") statements. And it seemed to me that each time the whole table is copied. After 5 or 6 plots, my machine (SL 4.1) killed the root.exe process which fullfilled the memory ( 1 GB + 2 GB of swap). Then I got no stack trace on stdout / stderr.

   The table has roughly 1 millions of rows with 400 columns each...                 

                                        Tristan

On 1 Feb 2006, at 17:38, Philippe Canal wrote:

> Hi Tristan,
>
> The size of the database should not cause a crash.
> However there was a bug recently fixed (in the CVS repository)
> that provoked a crash if the table contain any character string
> columns.
>
> Please try with ROOT from the head of the repository. If it
> still does not work, please send me a stack trace of where it
> crashed.
>
> Cheers,
> Philippe.
>
> -----Original Message-----
> From: owner-roottalk_at_pcroot.cern.ch [mailto:owner-
> roottalk_at_pcroot.cern.ch]
> On Behalf Of Tristan Beau
> Sent: Wednesday, February 01, 2006 9:31 AM
> To: roottalk_at_pcroot.cern.ch
> Subject: [ROOT] is TTreeSQL dumping the whole table ?
>
>
> Hello,
>
> I just discovered the new classe TTreeSQL. I tried to use it with
> a code such as :
>
> TSQLServer *s = TSQLServer::Connect("mysql://dbserv/db","user","pwd");
> TTreeSQL *t = new TTreeSQL(s,"db","atable");
>
> But then it crashes my session probably because the "atable" table
> is too big. Is TTreeSQL dumping the whole table with the constructor
> TTreeSQL ? This is a problem while accessing to very big tables ( > 1
> Go ). Which way should I use in such a case ?
>
> Thank's in advance,
>
> Tristan
>
> ---
> Tristan Beau http://www.apc.univ-paris7.fr/~beau/
> AstroParticules et Cosmologie
> 11 pl. M. Berthelot, 75231 Paris cedex 05
> tel: +33 1 44 27 14 46 , fax: +33 1 43 54 69 89
>
>
>

                                Tristan

---
Tristan Beau       http://www.apc.univ-paris7.fr/~beau/
AstroParticules et Cosmologie
11 pl. M. Berthelot, 75231 Paris cedex 05 tel: +33 1 44 27 14 46 , fax: +33 1 43 54 69 89 Received on Thu Feb 02 2006 - 09:18:24 MET

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