diff --git a/storage/innodb_plugin/include/row0ins.h b/storage/innodb_plugin/include/row0ins.h
index c780d228a45..810973e61a7 100644
--- a/storage/innodb_plugin/include/row0ins.h
+++ b/storage/innodb_plugin/include/row0ins.h
@@ -86,7 +86,8 @@ row_ins_index_entry(
 	dict_index_t*	index,	/*!< in: index */
 	dtuple_t*	entry,	/*!< in/out: index entry to insert */
 	ulint		n_ext,	/*!< in: number of externally stored columns */
-	ibool		foreign,/*!< in: TRUE=check foreign key constraints */
+	ibool		foreign,/*!< in: TRUE=check foreign key constraints
+				(foreign=FALSE only during CREATE INDEX) */
 	que_thr_t*	thr);	/*!< in: query thread */
 /***********************************************************//**
 Inserts a row to a table. This is a high-level function used in
diff --git a/storage/innodb_plugin/row/row0ins.c b/storage/innodb_plugin/row/row0ins.c
index 81b58465e11..298c601c7e3 100644
--- a/storage/innodb_plugin/row/row0ins.c
+++ b/storage/innodb_plugin/row/row0ins.c
@@ -2160,7 +2160,8 @@ row_ins_index_entry(
 	dict_index_t*	index,	/*!< in: index */
 	dtuple_t*	entry,	/*!< in/out: index entry to insert */
 	ulint		n_ext,	/*!< in: number of externally stored columns */
-	ibool		foreign,/*!< in: TRUE=check foreign key constraints */
+	ibool		foreign,/*!< in: TRUE=check foreign key constraints
+				(foreign=FALSE only during CREATE INDEX) */
 	que_thr_t*	thr)	/*!< in: query thread */
 {
 	ulint	err;