diff --git a/doc/src/sgml/perform.sgml b/doc/src/sgml/perform.sgml
index bd93cb0dd2ed58b072dd189310e7dd1fcaa7951e..a2f7e0629f7eabb6ce638948f2f372e1ad5b6b32 100644
--- a/doc/src/sgml/perform.sgml
+++ b/doc/src/sgml/perform.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/perform.sgml,v 1.77 2010/04/28 16:10:40 heikki Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/perform.sgml,v 1.78 2010/04/28 16:48:21 alvherre Exp $ -->
<chapter id="performance-tips">
<title>Performance Tips</title>
@@ -554,16 +554,31 @@ WHERE relname LIKE 'tenk1%';
For example, we might do:
<screen>
-SELECT attname, n_distinct, most_common_vals
+SELECT attname, inherited, n_distinct,
+ array_to_string(most_common_vals, E'\n') as most_common_vals
FROM pg_stats
WHERE tablename = 'road';
- attname | n_distinct | most_common_vals
----------+------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
- name | -0.467008 | {"I- 580 Ramp","I- 880 Ramp","Sp Railroad ","I- 580 ","I- 680 Ramp","I- 80 Ramp","14th St ","5th St ","Mission Blvd","I- 880 "}
- thepath | 20 | {"[(-122.089,37.71),(-122.0886,37.711)]"}
+ attname | inherited | n_distinct | most_common_vals
+---------+-----------+------------+------------------------------------
+ name | f | -0.363388 | I- 580 Ramp+
+ | | | I- 880 Ramp+
+ | | | Sp Railroad +
+ | | | I- 580 +
+ | | | I- 680 Ramp
+ name | t | -0.284859 | I- 880 Ramp+
+ | | | I- 580 Ramp+
+ | | | I- 680 Ramp+
+ | | | I- 580 +
+ | | | State Hwy 13 Ramp
(2 rows)
</screen>
+
+ Note that two rows are displayed for the same column, one corresponding
+ to the complete inheritance hierarchy starting at the
+ <literal>road</literal> table (<literal>inherited</>=<literal>t</>),
+ and another one including only the <literal>road</literal> table itself
+ (<literal>inherited</>=<literal>f</>).
</para>
<para>