Unusable resultset

I just did a query that would have returned impossible amounts of data,
eg: select * from BIGtable.  I am porting from Informix to Postgresql,
and I guess I have been spoiled by the IFX JDBC drivers, which return
only as much data, relatively speaking, as is needed.  When the IFX JDBC
driver runs out of data, it asks the backend for more data.  Apparently
the backend caches the results instead of shoving it all down the socket
to the JDBC driver all at once.  (Oh, how I wish PG JDBC did that.)

Anyway, when I did the above, I got back a null resultset.  I don't even
think it threw an exception (but I will try to check on that).  All of
that is fine and can be dealt with.  My real problem is that the
connection is no longer usable, as ANY query I perform throws a
"postgresql.con.type" exception.

Why does it do that, and what is a "type" exception?

I now catch this specific exception as an indication that the connection
is bad, after which I close it, but it sure is annoying to have to put
driver-specific code in my java codebase.  :(

--
Matt Mello