Log files have grown quite large (over 1.5 million entries)  When I select the  "delete all" button in the system log viewer in the support tab I get an error part of which is below. How can I delete the log files?

HTTP Status 500 -

---

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: java.sql.SQLException: Error during query: Unexpected Exception: java.lang.ArrayIndexOutOfBoundsException message given: 18692