/** Write data into the database. */
  private void generateData(
      Environment master, int numTxns, Durability durability, boolean doCommit) {

    /* Write some data. */
    DatabaseEntry key = new DatabaseEntry();
    byte[] dataPadding = new byte[1000];
    DatabaseEntry data = new DatabaseEntry(dataPadding);

    TransactionConfig txnConfig = new TransactionConfig();
    txnConfig.setDurability(durability);

    for (int i = 0; i < numTxns; i++) {
      final Transaction txn = master.beginTransaction(null, txnConfig);
      //            long keyPrefix = i << 10;
      //            LongBinding.longToEntry(keyPrefix + i, key);
      LongBinding.longToEntry(i, key);
      db.put(txn, key, data);

      if (doCommit) {
        txn.commit();
      } else {
        txn.abort();
      }
    }
  }