tname = tnm;
tname = name;
    public synchronized void begin(String tnm) throws Exception {        if (killed) {            throw new DatabaseException("Transaction started on killed thread");        }        if (active) {            abort();        }        nodes.clear();        nodesArray.clear();        cleannodes.clear();        txn = nmgr.db.beginTransaction();        active = true;        tstart = System.currentTimeMillis();        tname = tnm;    }