Index: maintenance/mysql5/tables.sql
===================================================================
--- maintenance/mysql5/tables.sql	(revision 16846)
+++ maintenance/mysql5/tables.sql	(working copy)
@@ -1004,7 +1004,7 @@
   job_params blob NOT NULL default '',
 
   PRIMARY KEY job_id (job_id),
-  KEY (job_cmd, job_namespace, job_title)
+  KEY (job_cmd(66), job_namespace, job_title)
 ) TYPE=InnoDB, DEFAULT CHARSET=utf8;
 
 -- Details of updates to cached special pages
Index: maintenance/tables.sql
===================================================================
--- maintenance/tables.sql	(revision 16846)
+++ maintenance/tables.sql	(working copy)
@@ -994,7 +994,7 @@
   job_params blob NOT NULL default '',
 
   PRIMARY KEY job_id (job_id),
-  KEY (job_cmd, job_namespace, job_title)
+  KEY (job_cmd(66), job_namespace, job_title)
 ) TYPE=InnoDB;