You might already be aware that Postgres updates the process title of all its running processes. For example, this is a Debian Linux ps display for an idle Postgres server:
postgres 2544 2543 0 10:47 ? 00:00:00 /u/pgsql/bin/postmaster -i postgres 2546 2544 0 10:47 ? 00:00:00 postgres: checkpointer process postgres 2547 2544 0 10:47 ? 00:00:00 postgres: writer process postgres 2548 2544 0 10:47 ? 00:00:00 postgres: wal writer process postgres 2558 2544 0 10:47 ? 00:00:01 postgres: autovacuum launcher process postgres 2575 2544 0 10:47 ? 00:00:02 postgres: stats collector process