[ROOT] TTree modification

From: Anton Fokin (anton.fokin@smartquant.com)
Date: Sun Feb 25 2001 - 11:24:28 MET


Hi Rene and rooters,

I saw another message on the roottalk about TTree modification. Rene, is
"one write - many read" policy your final answer? I still do not understand
why you do not want to provide (optional) insert/delete/modify entry
mechanism if you told once it is simple from technical point of view.

Here is a simple example of an application where ROOT fits data warehousing
needs but can not be efficiently used without TTree modifocation. Trade and
quote real time data from Reuters/Bloomberg and other providers are quite
similar to experimental on-line data. Every day you get a plane stream of
thousands of records ordered in time. Thus you can write them in a root tree
and beat any other RDBMS with the speed when you analyse this data
warehouse. One small detail breaks down this idyllic picture: after some
time you can get a signal saying that a record #xxx was not correct and the
next record is corrected #xxx.

The same happens when you want to mark certain events in the warehouse as
outliers. Etc. etc.

I would say that in general this feature prevents ROOT from spreading out in
the other than hep communities. One of such applications I have mentioned
above.

Should we discuss this tree modification topic within ROOT community and
formulate the final decision?

Regards,
Anton

http://www.smartquant.com



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