diff --git a/doc/src/sgml/ref/prepare_transaction.sgml b/doc/src/sgml/ref/prepare_transaction.sgml
index b8b8d8aca83149f23c3451bd938f5e264c75c396..da304c72550adbaeb0deabd0767cf12e873d2b16 100644
--- a/doc/src/sgml/ref/prepare_transaction.sgml
+++ b/doc/src/sgml/ref/prepare_transaction.sgml
@@ -1,5 +1,5 @@
@@ -82,6 +82,15 @@ PREPARE TRANSACTION transaction_id
Notes
+
+ PREPARE TRANSACTION> is not intended for use in applications
+ or interactive sessions. It's purpose is to allow an external
+ transaction manager to perform atomic global transactions across multiple
+ databases or other transactional resources. Unless you're writing a
+ transaction manager, you probably shouldn't be using PREPARE
+ TRANSACTION>.
+
+
This command must be used inside a transaction block. Use to start one.
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index da2011074ba2a8034cc29a1067d787e38c092fbf..cecd88d522ad6bcc13e3ea460611963328e8a03e 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -3,7 +3,7 @@
*
* Copyright (c) 2000-2010, PostgreSQL Global Development Group
*
- * $PostgreSQL: pgsql/src/bin/psql/tab-complete.c,v 1.191 2010/01/22 16:40:19 rhaas Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/tab-complete.c,v 1.192 2010/01/25 18:23:09 heikki Exp $
*/
/*----------------------------------------------------------------------
@@ -1882,6 +1882,11 @@ psql_completion(char *text, int start, int end)
COMPLETE_WITH_LIST(list_PREPARE);
}
+/*
+ * PREPARE TRANSACTION is missing on purpose. It's intended for transaction
+ * managers, not for manual use in interactive sessions.
+ */
+
/* REASSIGN OWNED BY xxx TO yyy */
else if (pg_strcasecmp(prev_wd, "REASSIGN") == 0)
COMPLETE_WITH_CONST("OWNED");