code: def db_query_execute(cls, cur, query, values, verbose=True):
          
          timeout = 1.0
  
          if verbose:
              log.debug(cls.db_format_query(query, values))
  
          while True:
              try:
                  ret = cur.execute(query, values)
                  return ret
              except sqlite3.OperationalError as oe:
                  if oe.message == "database is locked":
                      timeout = timeout * 2 + timeout * random.random()
                      log.error("Query timed out due to lock; retrying in %s: %s" % (timeout, cls.db_format_query( query, values )))
                      time.sleep(timeout)
                  
                  else:
                      log.exception(oe)
                      log.error("FATAL: failed to execute query (%s, %s)" % (query, values))
                      log.error("\n".join(traceback.format_stack()))
                      os.abort()
  
              except Exception, e:
                  log.exception(e)
                  log.error("FATAL: failed to execute query (%s, %s)" % (query, values))
                  log.error("\n".join(traceback.format_stack()))
                  os.abort()
docs: Execute a query.
          Handle db timeouts.
          Abort on failure.