private String openTxnAndGetValidTxnList() {
    String txnString = driverContext.getConf().get(ValidTxnList.VALID_TXNS_KEY);
    if (SessionState.get().isCompaction()) {
      return txnString;
    }
    HiveTxnManager txnMgr = driverContext.getTxnManager();
    try {
      openTransaction(txnMgr);
      if (txnMgr.isTxnOpen() && Strings.isEmpty(txnString)) {
        txnString = generateValidTxnList(txnMgr);
      }
    } catch (Exception e) {
      throw new RuntimeException("Failed to open a new transaction", e);
    }
    return txnString;
  }
Last repl id should be captured before opening txn by current REPL DUMP operation.
This is needed to avoid losing data which are added/modified by concurrent txns when bootstrap
dump in progress.
@param conf Query configurations
@throws HiveException
@throws TException
ql/src/java/org/apache/hadoop/hive/ql/Compiler.java