triggers and actions tree

Hello all,

I am new to postgreSQL.
When I perform an action on a psql database (e.g. insert into a table),
some more action could be induced, via trigger firing:
  - is it possible to know at any time the exact action chain?
  - is it possible to know at any time if the control is inside a
trigger (and which one)?
Sorry, I tried to search in www.postgresql.org  but I wasn't able to
find anything useful.

These questions arise because I'm trying to keep in sync two identical
psql databases; I have audited tables and an audit trail. I'm facing the
problem of recognising which actions in the trail were due to a trigger
firing, rather than explicitly commanded.

Thank you in advance
Fabio