From d76a149c955a6525c8d42425c57e32d74d2c2eed Mon Sep 17 00:00:00 2001
From: Magnus Hagander <magnus@hagander.net>
Date: Thu, 5 May 2011 21:47:42 +0200
Subject: [PATCH] Clarify error message when attempting to create index on
 foreign table

Instead of just saying "is not a table", specifically state that
indexes aren't supported on *foreign* tables.
---
 src/backend/commands/indexcmds.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index ff84045d4f..b91e4a4bd2 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -183,10 +183,22 @@ DefineIndex(RangeVar *heapRelation,
 	/* Note: during bootstrap may see uncataloged relation */
 	if (rel->rd_rel->relkind != RELKIND_RELATION &&
 		rel->rd_rel->relkind != RELKIND_UNCATALOGED)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table",
-						heapRelation->relname)));
+	{
+		if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
+			/*
+			 * Custom error message for FOREIGN TABLE since the term is
+			 * close to a regular table and can confuse the user.
+			 */
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot create index on foreign table \"%s\"",
+						 heapRelation->relname)));
+		else
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("\"%s\" is not a table",
+							heapRelation->relname)));
+	}
 
 	/*
 	 * Don't try to CREATE INDEX on temp tables of other backends.