diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index f5f2079..13c8c81 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -3933,20 +3933,19 @@ SELECT * FROM sales_summary_bytime;
    <title>Triggers on commands</title>
 
    <para>
-    <application>PL/pgSQL</application> can be used to define trigger
-    procedures. A trigger procedure is created with the
+    <application>PL/pgSQL</application> can be used to define command 
+    trigger procedures. A command trigger procedure is created with the
     <command>CREATE FUNCTION</> command, declaring it as a function with
     no arguments and a return type of <type>command trigger</type>.
    </para>
 
   <para>
    When a <application>PL/pgSQL</application> function is called as a
-   trigger, several special variables are created automatically in the
-   top-level block. They are:
+   command trigger, several special variables are created automatically
+   in the top-level block. They are:
 
    <variablelist>
     <varlistentry>
-    <varlistentry>
      <term><varname>TG_TAG</varname></term>
      <listitem>
       <para>
@@ -4002,7 +4001,7 @@ SELECT * FROM sales_summary_bytime;
   </para>
 
   <para>
-   The command trigger function return's value is not used.
+   The command trigger function's return value is not used.
   </para>
 
    <para>
@@ -4014,23 +4013,20 @@ SELECT * FROM sales_summary_bytime;
     <title>A <application>PL/pgSQL</application> Command Trigger Procedure</title>
 
     <para>
-     This example trigger just raise a <literal>NOTICE</literal> message
+     This example trigger simply raises a <literal>NOTICE</literal> message
      each time a supported command is executed.
     </para>
 
 <programlisting>
-create or replace function snitch()
- returns command trigger
- language plpgsql
-as $$
-begin
-  raise notice 'snitch: % % %.% [%]',
+CREATE OR REPLACE FUNCTION snitch() RETURNS command trigger AS $$
+BEGIN
+    RAISE NOTICE 'snitch: % % %.% [%]',
                tg_when, tg_tag, tg_schemaname, tg_objectname, tg_objectid;
-end;
-$$;
+END;
+$$ LANGUAGE plpgsql;
 
-create command trigger snitch_before before any command execute procedure any_snitch();
-create command trigger snitch_after after any command execute procedure any_snitch();
+CREATE COMMAND TRIGGER snitch_before BEFORE ANY COMMAND EXECUTE PROCEDURE snitch();
+CREATE COMMAND TRIGGER snitch_after AFTER ANY COMMAND EXECUTE PROCEDURE snitch();
 </programlisting>
    </example>
   </sect2>
diff --git a/doc/src/sgml/ref/create_command_trigger.sgml b/doc/src/sgml/ref/create_command_trigger.sgml
index fc12d2e..01c7826 100644
--- a/doc/src/sgml/ref/create_command_trigger.sgml
+++ b/doc/src/sgml/ref/create_command_trigger.sgml
@@ -30,7 +30,6 @@ CREATE COMMAND TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFOR
 <phrase>where <replaceable class="parameter">command</replaceable> can be one of:</phrase>
 
     ALTER AGGREGATE
-    ALTER CAST
     ALTER COLLATION
     ALTER CONVERSION
     ALTER DOMAIN
@@ -56,6 +55,7 @@ CREATE COMMAND TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFOR
     ALTER VIEW
     CLUSTER
     CREATE AGGREGATE
+    CREATE CAST
     CREATE COLLATION
     CREATE CONVERSION
     CREATE DOMAIN
@@ -186,14 +186,12 @@ CREATE COMMAND TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFOR
       That leaves out the following list of non supported commands.
      </para>
      <para>
-      Commands that refers to global objects, such as databases, tablespaces
-      and roles are not supported. As command triggers are per-database, it
-      would be weird to affect e.g. a tablespace depending on which database
-      you are connected to.
+      Commands that refer to global objects, such as databases, tablespaces
+      and roles, are not supported.
      </para>
      <para>
       Commands that exercise their own transaction control are only
-      supported in <literal>BEFORE</literal> command triggers, that's the
+      supported in <literal>BEFORE</literal> command triggers.  This is the
       case for <literal>VACUUM</literal>, <literal>CLUSTER</literal>,
       <literal>CREATE INDEX CONCURRENTLY</literal>, and <literal>REINDEX
       DATABASE</literal>.
@@ -220,11 +218,6 @@ CREATE COMMAND TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFOR
       not to be able to take over control from a superuser.
      </para>
      <para>
-      Triggers on ANY command support more commands than just this list, and
-      will provide NULL values for every argument except for the argument
-      that determines whether the trigger was before or after the command
-      event, and the command tag.
-
       Triggers on <literal>ANY</literal> command support more commands than
       just this list, and will only provide the <literal>command
       tag</literal> argument as <literal>NOT NULL</literal>. Supporting more
@@ -238,12 +231,12 @@ CREATE COMMAND TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFOR
     <term><replaceable class="parameter">function_name</replaceable></term>
     <listitem>
      <para>
-      A user-supplied function that is declared as taking 5 arguments of
-      type text, text, oid, text, text and returning void.
+      A user-supplied function that is declared as taking no argument and
+      returning type <literal>command trigger</literal>.
      </para>
      <para>
       If your command trigger is implemented in <literal>C</literal> then it
-      will be called with yet another argument, of
+      will be called with an argument, of
       type <literal>internal</literal>, which is a pointer to
       the <literal>Node *</literal> parse tree.
      </para>
@@ -275,7 +268,7 @@ CREATE COMMAND TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFOR
 CREATE OR REPLACE FUNCTION abort_any_command()
  RETURNS command trigger LANGUAGE plpgsql AS $$
 BEGIN
-  RAISE EXCEPTION 'command % is disabled' % tg_tag;
+  RAISE EXCEPTION 'command % is disabled', tg_tag;
 END;
 $$;
 
diff --git a/src/backend/commands/cmdtrigger.c b/src/backend/commands/cmdtrigger.c
index 6f134d5..f06f6b9 100644
--- a/src/backend/commands/cmdtrigger.c
+++ b/src/backend/commands/cmdtrigger.c
@@ -191,7 +191,7 @@ CreateCmdTrigger(CreateCmdTrigStmt *stmt, const char *queryString)
 	if (funcrettype != CMDTRIGGEROID)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
-				 errmsg("function \"%s\" must return type \"trigger\"",
+				 errmsg("function \"%s\" must return type \"command trigger\"",
 						NameListToString(stmt->funcname))));
 
 	trigoid = InsertCmdTriggerTuple(tgrel, stmt->command, stmt->trigname,