diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..ff825b5b45f 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -70,13 +70,13 @@ typedef struct CompactAttribute
 	int32		attcacheoff;	/* fixed offset into tuple, if known, or -1 */
 	int16		attlen;			/* attr len in bytes or -1 = varlen, -2 =
 								 * cstring */
-	bool		attbyval;		/* as FormData_pg_attribute.attbyval */
-	bool		attispackable;	/* FormData_pg_attribute.attstorage !=
+	bool		attbyval:1;		/* as FormData_pg_attribute.attbyval */
+	bool		attispackable:1;	/* FormData_pg_attribute.attstorage !=
 								 * TYPSTORAGE_PLAIN */
-	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
-	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
-	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	bool		atthasmissing:1;	/* as FormData_pg_attribute.atthasmissing */
+	bool		attisdropped:1;	/* as FormData_pg_attribute.attisdropped */
+	bool		attgenerated:1;	/* FormData_pg_attribute.attgenerated != '\0' */
+	bool		attnotnull:1;		/* as FormData_pg_attribute.attnotnull */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;