多机部署下，所有机器都宕机，从异常中恢复时，所有的机器岂不是都可以查询到所有的需要恢复的服务？

这里查询出了所有的超时服务

@Override
    protected List<Transaction> doFindAllUnmodifiedSince(java.util.Date date) {

        List<Transaction> transactions = new ArrayList<Transaction>();

        Connection connection = null;
        PreparedStatement stmt = null;

        try {
            connection = this.getConnection();

            StringBuilder builder = new StringBuilder();

            builder.append("SELECT GLOBAL_TX_ID, BRANCH_QUALIFIER, CONTENT,STATUS,TRANSACTION_TYPE,CREATE_TIME,LAST_UPDATE_TIME,RETRIED_COUNT,VERSION");
            builder.append(StringUtils.isNotEmpty(domain) ? ",DOMAIN" : "");
            builder.append("  FROM " + getTableName() + " WHERE LAST_UPDATE_TIME < ?");
            builder.append(StringUtils.isNotEmpty(domain) ? " AND DOMAIN = ?" : "");

            stmt = connection.prepareStatement(builder.toString());

            stmt.setTimestamp(1, new Timestamp(date.getTime()));

            if (StringUtils.isNotEmpty(domain)) {
                stmt.setString(2, domain);
            }

            ResultSet resultSet = stmt.executeQuery();

            while (resultSet.next()) {
                byte[] transactionBytes = resultSet.getBytes(3);
                Transaction transaction = (Transaction) serializer.deserialize(transactionBytes);
                transaction.changeStatus(TransactionStatus.valueOf(resultSet.getInt(4)));
                transaction.setLastUpdateTime(resultSet.getDate(7));
                transaction.setVersion(resultSet.getLong(9));
                transaction.resetRetriedCount(resultSet.getInt(8));
                transactions.add(transaction);
            }
        } catch (Throwable e) {
            throw new TransactionIOException(e);
        } finally {
            closeStatement(stmt);
            this.releaseConnection(connection);
        }

        return transactions;
    }

初看了下源码，这里用到了version，乐观锁可以解决大部分并发行为么？

protected int doUpdate(Transaction transaction) {
        Connection connection = null;
        PreparedStatement stmt = null;

        java.util.Date lastUpdateTime = transaction.getLastUpdateTime();
        long currentVersion = transaction.getVersion();

        transaction.updateTime();
        transaction.updateVersion();

        try {
            connection = this.getConnection();

            StringBuilder builder = new StringBuilder();
            builder.append("UPDATE " + getTableName() + " SET " +
                    "CONTENT = ?,STATUS = ?,LAST_UPDATE_TIME = ?, RETRIED_COUNT = ?,VERSION = VERSION+1 WHERE GLOBAL_TX_ID = ? AND BRANCH_QUALIFIER = ? AND VERSION = ?");

            builder.append(StringUtils.isNotEmpty(domain) ? " AND DOMAIN = ?" : "");

            stmt = connection.prepareStatement(builder.toString());

            stmt.setBytes(1, serializer.serialize(transaction));
            stmt.setInt(2, transaction.getStatus().getId());
            stmt.setTimestamp(3, new Timestamp(transaction.getLastUpdateTime().getTime()));

            stmt.setInt(4, transaction.getRetriedCount());
            stmt.setBytes(5, transaction.getXid().getGlobalTransactionId());
            stmt.setBytes(6, transaction.getXid().getBranchQualifier());
            stmt.setLong(7, currentVersion);

            if (StringUtils.isNotEmpty(domain)) {
                stmt.setString(8, domain);
            }

            int result = stmt.executeUpdate();

            return result;

        } catch (Throwable e) {
            transaction.setLastUpdateTime(lastUpdateTime);
            transaction.setVersion(currentVersion);
            throw new TransactionIOException(e);
        } finally {
            closeStatement(stmt);
            this.releaseConnection(connection);
        }
    }

changmingxie / tcc-transaction

多机部署下，所有机器都宕机，从异常中恢复时，所有的机器岂不是都可以查询到所有的需要恢复的服务？ #98