I was reviving an old test program which hasn't been used since 9.1 and found that "SET search_path = xyzzy" no longer fails if the schema "xyzzy" doesn't exist.
Is there an approved or recommended way to tell if a schema exists? I can think of lots of ways, but none as easy as the 9.1 search_path. I suppose I shouldn't rely on undocumented features ...
How about:
SELECT TRUE FROM information_schema.schemata WHERE schema_name = 'xyzzy'
? (Though I notice this table only seems to show the schemas owned by the user if the user is not a superuser).