insert fail gracefully if primary key already exists - Mailing list pgsql-novice

I have a situation where I am gradually filling in a table from another database as the need requires. As it currently is, whenever a record comes up, it tries to insert it into my database. If the row is already there, the primary key collides and the insert fails. And that's fine except that it makes for a really cluttered log (making it hard to find errors that I really do need to pay attention to). I'm wondering if there's a better (i.e. cleaner, but possibly also more efficient) way to do this.