Document permissions needed for pg_database_size and pg_tablespace_size.

Back in 8.3, we installed permissions checks in these functions (see
commits 8bc225e7990a and cc26599b7206).  But we forgot to document that
anywhere in the user-facing docs; it did get mentioned in the 8.3 release
notes, but nobody's looking at that any more.  Per gripe from Suya Huang.

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d04dd747af8631c80160ce5871d4f63e36575360..5126f14eb6a4f63ed7360a985e7496da8160ff57 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -16946,7 +16946,11 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
    
     pg_database_size and pg_tablespace_size
     accept the OID or name of a database or tablespace, and return the total
-    disk space used therein.
+    disk space used therein.  To use pg_database_size,
+    you must have CONNECT permission on the specified database
+    (which is granted by default).  To use pg_tablespace_size,
+    you must have CREATE permission on the specified tablespace,
+    unless it is the default tablespace for the current database.