Normally when a DB transaction is blocked on a lock request, it must wait until the requested lock becomes available before its thread-of-control can proceed. However, it is possible to configure a transaction handle such that it will report a deadlock rather than wait for the block to clear.
            You do this on a transaction by transaction basis by specifying
            
                DB_TXN_NOWAIT
                to the
                
                DbEnv::txn_begin()
                
                method.
            
            
            
        
For example:
    DbTxn *txn = NULL;
    try {
        envp->txn_begin(NULL, &txn, DB_TXN_NOWAIT);
        ...
    } catch (DbException &de) {
        // Deadlock detection and exception handling omitted
        // for brevity
        ...