Replace functional-index facility with expressional indexes. Any column

of an index can now be a computed expression instead of a simple variable.
Restrictions on expressions are the same as for predicates (only immutable
functions, no sub-selects).  This fixes problems recently introduced with
inlining SQL functions, because the inlining transformation is applied to
both expression trees so the planner can still match them up.  Along the
way, improve efficiency of handling index predicates (both predicates and
index expressions are now cached by the relcache) and fix 7.3 oversight
that didn't record dependencies of predicate expressions.

src/tutorial/syscat.source

@@ -7,7 +7,7 @@
 -- Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
 -- Portions Copyright (c) 1994, Regents of the University of California
 --
--- $Id: syscat.source,v 1.7 2002/06/20 20:29:54 momjian Exp $
+-- $Id: syscat.source,v 1.8 2003/05/28 16:04:02 tgl Exp $
 --
 ---------------------------------------------------------------------------
 
@@ -31,8 +31,8 @@ SELECT relname
 
 
 --
--- lists all simple indices (ie. those that are not defined over a function
--- of several attributes)
+-- lists all simple indices (ie. those that are defined over one simple
+-- column reference)
 --
 SELECT bc.relname AS class_name, 
        ic.relname AS index_name, 
@@ -44,8 +44,8 @@ SELECT bc.relname AS class_name,
   WHERE i.indrelid = bc.oid
      and i.indexrelid = ic.oid
      and i.indkey[0] = a.attnum
+     and i.indnatts = 1
      and a.attrelid = bc.oid
-     and i.indproc = '0'::oid   -- no functional indices
   ORDER BY class_name, index_name, attname;