diff --git a/db/pf-schema-X.Y.sql b/db/pf-schema-X.Y.sql
index 7c642f31c81..96b2ba4fd66 100644
--- a/db/pf-schema-X.Y.sql
+++ b/db/pf-schema-X.Y.sql
@@ -1507,7 +1507,7 @@ CREATE TABLE `pki_certs` (
   `alert` tinyint(1) DEFAULT 0,
   `subject` longtext DEFAULT NULL,
   PRIMARY KEY (`id`),
-  UNIQUE KEY `cn_serial` (`cn`,`serial_number`) USING HASH,
+  UNIQUE KEY `cn_serial` (`cn`(127),`serial_number`(127)) USING HASH,
   KEY `ca_id` (`ca_id`),
   KEY `ca_name` (`ca_name`),
   KEY `profile_name` (`profile_name`),