How triggers behave wrt concurrent visibility of transactions?

I'm working 开发者_如何学Con PostgreSQL 8.4 in read committed mode. I know that for each query, the server makes a snapshot of db state so that the query behaves consistently. Does it include triggers that are called in response to this query? Or is there a new snapshot created for each query called from within a trigger?

Triggers work in the same transaction as the outer query, it will see the same snapshot.