diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index bf27c6f70d..9524d2810a 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -1781,8 +1781,16 @@ addRangeTableEntryForFunction(ParseState *pstate,
 
 			/*
 			 * Use the column definition list to construct a tupdesc and fill
-			 * in the RangeTblFunction's lists.
+			 * in the RangeTblFunction's lists.  Limit number of columns to
+			 * MaxHeapAttributeNumber, because CheckAttributeNamesTypes will.
 			 */
+			if (list_length(coldeflist) > MaxHeapAttributeNumber)
+				ereport(ERROR,
+						(errcode(ERRCODE_TOO_MANY_COLUMNS),
+						 errmsg("column definition lists can have at most %d entries",
+								MaxHeapAttributeNumber),
+						 parser_errposition(pstate,
+											exprLocation((Node *) coldeflist))));
 			tupdesc = CreateTemplateTupleDesc(list_length(coldeflist));
 			i = 1;
 			foreach(col, coldeflist)
@@ -1862,6 +1870,15 @@ addRangeTableEntryForFunction(ParseState *pstate,
 		if (rangefunc->ordinality)
 			totalatts++;
 
+		/* Disallow more columns than will fit in a tuple */
+		if (totalatts > MaxTupleAttributeNumber)
+			ereport(ERROR,
+					(errcode(ERRCODE_TOO_MANY_COLUMNS),
+					 errmsg("functions in FROM can return at most %d columns",
+							MaxTupleAttributeNumber),
+					 parser_errposition(pstate,
+										exprLocation((Node *) funcexprs))));
+
 		/* Merge the tuple descs of each function into a composite one */
 		tupdesc = CreateTemplateTupleDesc(totalatts);
 		natts = 0;
@@ -1946,6 +1963,18 @@ addRangeTableEntryForTableFunc(ParseState *pstate,
 
 	Assert(pstate != NULL);
 
+	/* Disallow more columns than will fit in a tuple */
+	if (list_length(tf->colnames) > MaxTupleAttributeNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_TOO_MANY_COLUMNS),
+				 errmsg("functions in FROM can return at most %d columns",
+						MaxTupleAttributeNumber),
+				 parser_errposition(pstate,
+									exprLocation((Node *) tf))));
+	Assert(list_length(tf->coltypes) == list_length(tf->colnames));
+	Assert(list_length(tf->coltypmods) == list_length(tf->colnames));
+	Assert(list_length(tf->colcollations) == list_length(tf->colnames));
+
 	rte->rtekind = RTE_TABLEFUNC;
 	rte->relid = InvalidOid;
 	rte->subquery = NULL;