Minor tweaks

Signed-off-by: Matt Lord <mattalord@gmail.com>

go/vt/vttablet/tabletmanager/rpc_vreplication.go

@@ -62,20 +62,22 @@ const (
 	// Check if workflow is still copying.
 	sqlGetVReplicationCopyStatus = "select distinct vrepl_id from %s.copy_state where vrepl_id = %d"
 	// Validate the minimum set of permissions needed to manage vreplication metadata.
+	// This is a simple check for a matching user rather than any specific user@host
+	// combination.
 	sqlValidateVReplicationPermissions = `
 select if(count(*)>0, 1, 0) as good from mysql.user as u
   left join mysql.db as d on (u.user = d.user)
   left join mysql.tables_priv as t on (u.user = t.user)
 where u.user = %a
   and (
-    (u.insert_priv = 'y' and u.update_priv = 'y' and u.delete_priv = 'y')
-    or (d.db = %a and u.insert_priv = 'y' and u.update_priv = 'y' and u.delete_priv = 'y')
-    or (t.db = %a and t.table_name = 'vreplication'
+    (u.insert_priv = 'y' and u.update_priv = 'y' and u.delete_priv = 'y') /* user has global privs */
+    or (d.db = %a and u.insert_priv = 'y' and u.update_priv = 'y' and u.delete_priv = 'y') /* user has db privs */
+    or (t.db = %a and t.table_name = 'vreplication' /* user has table privs */
       and find_in_set('insert', t.table_priv)
       and find_in_set('update', t.table_priv)
       and find_in_set('delete', t.table_priv)
     )
-  )
+  ) limit 1
 `
 )