diff --git a/doc/src/sgml/ref/do.sgml b/doc/src/sgml/ref/do.sgml
index a85d598c6a..f9e06ca092 100644
--- a/doc/src/sgml/ref/do.sgml
+++ b/doc/src/sgml/ref/do.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/do.sgml,v 1.3 2010/01/26 16:33:40 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/do.sgml,v 1.4 2010/02/15 02:55:01 itagaki Exp $
 PostgreSQL documentation
 -->
 
@@ -25,7 +25,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-DO <replaceable class="PARAMETER">code</replaceable> [ LANGUAGE <replaceable class="PARAMETER">lang_name</replaceable> ]
+DO { [ LANGUAGE <replaceable class="PARAMETER">lang_name</replaceable> ] | <replaceable class="PARAMETER">code</replaceable> } ...
 </synopsis>
  </refsynopsisdiv>
 
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index cecd88d522..19b9b1f3ef 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 1.192 2010/01/25 18:23:09 heikki Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/tab-complete.c,v 1.193 2010/02/15 02:55:01 itagaki Exp $
  */
 
 /*----------------------------------------------------------------------
@@ -618,7 +618,7 @@ psql_completion(char *text, int start, int end)
 	static const char *const sql_commands[] = {
 		"ABORT", "ALTER", "ANALYZE", "BEGIN", "CHECKPOINT", "CLOSE", "CLUSTER",
 		"COMMENT", "COMMIT", "COPY", "CREATE", "DEALLOCATE", "DECLARE",
-		"DELETE FROM", "DISCARD", "DROP", "END", "EXECUTE", "EXPLAIN", "FETCH",
+		"DELETE FROM", "DISCARD", "DO", "DROP", "END", "EXECUTE", "EXPLAIN", "FETCH",
 		"GRANT", "INSERT", "LISTEN", "LOAD", "LOCK", "MOVE", "NOTIFY", "PREPARE",
 		"REASSIGN", "REINDEX", "RELEASE", "RESET", "REVOKE", "ROLLBACK",
 		"SAVEPOINT", "SELECT", "SET", "SHOW", "START", "TABLE", "TRUNCATE", "UNLISTEN",
@@ -1532,6 +1532,18 @@ psql_completion(char *text, int start, int end)
 		COMPLETE_WITH_LIST(list_DISCARD);
 	}
 
+/* DO */
+	/*
+	 * Complete DO with LANGUAGE.
+	 */
+	else if (pg_strcasecmp(prev_wd, "DO") == 0)
+	{
+		static const char *const list_DO[] =
+		{"LANGUAGE", NULL};
+
+		COMPLETE_WITH_LIST(list_DO);
+	}
+
 /* DROP (when not the previous word) */
 	/* DROP AGGREGATE */
 	else if (pg_strcasecmp(prev3_wd, "DROP") == 0 &&