diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 5204b34..6ec041a 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -497,18 +497,24 @@
    <para>
     The sole disadvantage of increasing <varname>autovacuum_freeze_max_age</>
     (and <varname>vacuum_freeze_table_age</> along with it)
-    is that the <filename>pg_clog</> subdirectory of the database cluster
-    will take more space, because it must store the commit status of all
-    transactions back to the <varname>autovacuum_freeze_max_age</> horizon.
-    The commit status uses two bits per transaction, so if
-    <varname>autovacuum_freeze_max_age</> is set to its maximum allowed
-    value of two billion, <filename>pg_clog</> can be expected to
-    grow to about half a gigabyte.  If this is trivial compared to your
-    total database size, setting <varname>autovacuum_freeze_max_age</> to
-    its maximum allowed value is recommended.  Otherwise, set it depending
-    on what you are willing to allow for <filename>pg_clog</> storage.
-    (The default, 200 million transactions, translates to about 50MB of
-    <filename>pg_clog</> storage.)
+    is that the <filename>pg_clog</> and <filename>pg_commit_ts</>
+    subdirectories of the database cluster will take more space, because they
+    must store the commit status and (if <varname>track_commit_timestamp</> is
+    enabled) timestamp of all transactions back to
+    the <varname>autovacuum_freeze_max_age</> horizon.  The commit status uses
+    two bits per transaction, so if
+    <varname>autovacuum_freeze_max_age</> is set to its maximum allowed value
+    of two billion, <filename>pg_clog</> can be expected to grow to about half
+    a gigabyte.  If this is trivial compared to your total database size and
+    you are not using commit timestamps,
+    setting <varname>autovacuum_freeze_max_age</> to its maximum allowed value
+    is recommended.  Otherwise, set it depending on what you are willing to
+    allow for <filename>pg_clog</> and <filename>pg_commit_ts</> storage.
+    Commit timestamps occupy 10 bytes per transaction
+    if <varname>track_commit_timestamp</> is enabled.  (The default, 200
+    million transactions, translates to about 50MB of
+    <filename>pg_clog</> storage and about 2GB of
+    <filename>pg_commit_ts</filename>.)
    </para>
 
    <para>