[Asterisk-Dev] How does Asterisk choose the CDr backend to use?

[David Filion]

Hi,

I'm trying to understand how Asterisk chooses the backend it's going to 
use for storing CDRs.
For example, if PostgreSQL, MySQL, and FreeTDS are installed, how does 
Asterisk know
which one to choose? Does it choose which ever one is configured are 
forget about the rest
or will it send a CDR to each configured backend?

The reason I'm asking is because I've been asked to put in logic that 
will write CDRs to a local
file if the CDR engine cannot send the CDR to the DB being used.

Thanks,

David Filion