No. PSQL autocommits unless you wrap your commands in BEGIN/END. Which, BTW, is something I do by habit having been bit in the ass myself by this once.
This may be something we should document since the PG people don't seem to really understand how easy it is for folks used to other database engines to assume that PSQL isn't autocommitting commands that are executed.
SQL*Plus, for instance, doesn't commit until you do an explicit COMMIT or exit the session.
