Solaris doesn't ship with top or with a version of ps that shows updated process titles in the default PATH. You can use /usr/ucb/ps and /usr/ucb/top to get versions that are more likely to display this information. In general, getting the process titles to show under Solaris is more difficult, and there are some restrictions on when it happens. There are some additional notes on this subject in the Standard Unix Tools section of http://www.postgresql.org/docs/current/interactive/monitoring.html.
The standard Solaris monitoring tool recommended instead of top is prstat. This utility is fine for monitoring overall system activity, but without being able to display the process title updates it's much less useful than ...
