diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 85f7c75c99..833753aede 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -1,5 +1,5 @@
@@ -689,8 +689,8 @@ ALTER TABLE name
Adding a column with a non-null default or changing the type of an
- existing column will require the entire table to be rewritten. This
- might take a significant amount of time for a large table; and it will
+ existing column will require the entire table and indexes to be rewritten.
+ This might take a significant amount of time for a large table; and it will
temporarily require double the disk space. Adding or removing a system
oid> column likewise requires rewriting the entire table.