Re: [Gnumed-devel] Where to start with gnumed

[Horst Herb]

Hilmar Berger wrote:

> What is the expected performance tradeoff when using XML-RPC vs. direct
> backend access ? After all , XML-RPC means
> GUI->XML-Layer->Socket->XML-Layer->Business-objects->Backend, that is at
> least 3 levels more while accessing the backend.

Since the GUI accesses these objects at the highest possible level, the 
performance tradeoff is minimal. All heavy database interaction happens 
between the service and the backend directly via the SQL backend protocol.

Example: the GUI client needs a list of all patients "starting with 'H* 
He*' living in Australia"
The client sends this search string to the service. The service marshals 
the request into a backend query, fetches the results, and forwards the 
digested results to the client in the format the client needs them.

Then, the clients wants all demographic data of a selected person. It 
sends the request to the service. The service then does all neccessary 
queries *which might be quite complex*) and again send the digested 
information back to the client.

Furthermore, the services can acively cache information or even 
heuristically "read ahead": query in a background procesinformation that 
is likely to be needed next, and cache it.

And on top of all this, you can easily load balance if performance is an 
issue: if your GUI desktop workstation is to weak, run one or more of 
these services on an old GUI-less machine for which their processing 
power is adequate.

Horst