1 files changed, 44 insertions, 18 deletions

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 2a943f9c6a5..e5faf46a7a6 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2132,27 +2132,53 @@ static Query *
 transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 {
 	Query	   *result;
+	Query	   *query;
 
-	/*
-	 * Set relkind in IntoClause based on statement relkind.  These are
-	 * different types, because the parser users the ObjectType enumeration
-	 * and the executor uses RELKIND_* defines.
-	 */
-	switch (stmt->relkind)
+	/* transform contained query */
+	query = transformStmt(pstate, stmt->query);
+	stmt->query = (Node *) query;
+
+	/* additional work needed for CREATE MATERIALIZED VIEW */
+	if (stmt->relkind == OBJECT_MATVIEW)
 	{
-		case (OBJECT_TABLE):
-			stmt->into->relkind = RELKIND_RELATION;
-			break;
-		case (OBJECT_MATVIEW):
-			stmt->into->relkind = RELKIND_MATVIEW;
-			break;
-		default:
-			elog(ERROR, "unrecognized object relkind: %d",
-				 (int) stmt->relkind);
-	}
+		/*
+		 * Prohibit a data-modifying CTE in the query used to create a
+		 * materialized view. It's not sufficiently clear what the user would
+		 * want to happen if the MV is refreshed or incrementally maintained.
+		 */
+		if (query->hasModifyingCTE)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use data-modifying statements in WITH")));
 
-	/* transform contained query */
-	stmt->query = (Node *) transformStmt(pstate, stmt->query);
+		/*
+		 * Check whether any temporary database objects are used in the
+		 * creation query. It would be hard to refresh data or incrementally
+		 * maintain it if a source disappeared.
+		 */
+		if (isQueryUsingTempRelation(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use temporary tables or views")));
+
+		/*
+		 * A materialized view would either need to save parameters for use in
+		 * maintaining/loading the data or prohibit them entirely.  The latter
+		 * seems safer and more sane.
+		 */
+		if (query_contains_extern_params(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views may not be defined using bound parameters")));
+
+		/*
+		 * At runtime, we'll need a copy of the parsed-but-not-rewritten Query
+		 * for purposes of creating the view's ON SELECT rule.  We stash that
+		 * in the IntoClause because that's where intorel_startup() can
+		 * conveniently get it from.
+		 */
+		stmt->into->viewQuery = copyObject(query);
+	}
 
 	/* represent the command as a utility Query */
 	result = makeNode(Query);