Scaling PostgreSQL TRIGGER(s)

How PSQL TRIGGER(s) mechanism scales ?

We have a large PostgreSQL installation and we are trying to implement an event based system using log tables and TRIGGER(s).

Basically we would like to create a TRIGGER for each table we want to be notified for an UPDATE/INSERT/DELETE operation. Once this trigger fires it will execute a function that will simply append a new row (encoding the event) to a log table that we will then poll from an external service.

Before going all in with Psql TRIGGER(s) we would like to know how they scale: how many triggers can we create on a single PSQL installation? Does they affect query performance? Did anyone before tried this ?