Minor editorialization on CLUSTER reference page.

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index c038d387c819944fb73992705ff0c64cedb89a44..acb2468f7ba5d667406c9445a51dc7bcbd9dfc05 100644 (file)
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -1,5 +1,5 @@
 
 
@@ -20,7 +20,7 @@ PostgreSQL documentation
 
  
 
-CLUSTER tablename [ USING indexname ]
+CLUSTER tablename  USING indexname 
 CLUSTER
 
  
@@ -43,22 +43,24 @@ CLUSTER
    based on the index information. Clustering is a one-time operation:
    when the table is subsequently updated, the changes are
    not clustered.  That is, no attempt is made to store new or
-   updated rows according to their index order.  If one wishes, one can
-   periodically recluster by issuing the command again.
+   updated rows according to their index order.  (If one wishes, one can
+   periodically recluster by issuing the command again.  Also, setting
+   the table's FILLFACTOR storage parameter to less than 100% can aid
+   in preserving cluster ordering during updates, since updated rows
+   are preferentially kept on the same page.)
   
 
   
    When a table is clustered, PostgreSQL
-   remembers on which index it was clustered.  The form
+   remembers which index it was clustered by.  The form
    CLUSTER tablename
-   reclusters the table on the same index that it was clustered before.
+   reclusters the table using the same index as before.
   
 
   
-   CLUSTER without any parameter reclusters all the tables
-   in the
-   current database that the calling user owns, or all tables if called
-   by a superuser.  (Never-clustered tables are not included.)  This
+   CLUSTER without any parameter reclusters all the
+   previously-clustered tables in the current database that the calling user
+   owns, or all such tables if called by a superuser.  This
    form of CLUSTER cannot be executed inside a transaction
    block.
   
@@ -197,12 +199,16 @@ CLUSTER;
   Compatibility
 
   
-   The syntax:
+   There is no CLUSTER statement in the SQL standard.
+  
+
+  
+   The syntax
 
 CLUSTER indexname ON tablename
 
-  is also supported for compatibility with pre-8.3 PostgreSQL installations.
-  There is no CLUSTER statement in the SQL standard.
+  is also supported for compatibility with pre-8.3 PostgreSQL
+  versions.