Oracle 在2009年收购了Golden Gate，之后Oracle 把Stream 的一些优点引入到了Golden Gate。 所以以后在数据复制这块，Oracle 肯定也是大力发展Golden Gate。
官网参考：
http://www.oracle.com/us/corporate/Acquisitions/goldengate/index.html
Golden Gate复制原理是通过挖掘Oracle的日志（redo和归档），然后生成自己的队列文件，通过队列文件传输到目标端，目标端通过读取相应的队列文件在目标数据库中重演事务。
Golden Gate 可以跨不同的数据库进行复制，如Oracle、IBM DB2、MS SQL Server等。Quest 公司也有一个复制软件：SharePlex，不过它只支持Oracle到Oracle的复制。用过Toad 的人应该都知道Quest 公司。
在联机文档上找了点这块的资料，粘贴如下，有空在研究下Golden Gate.
Oracle Database High Availability Solutions for Unplanned Downtime
http://download.oracle.com/docs/cd/E11882_01/server.112/e17157/unplanned.htm#HAOVW121
3.7 Oracle GoldenGate and Oracle Streams
Oracle GoldenGate is Oracle's strategic product for data distribution and data integration. It is a high-performance software application that uses log-based bidirectional data replication for real-time capture, transformation, routing, and delivery of database transactions across heterogeneous systems.（GG 说明）Oracle GoldenGate helps you achieve continuous availability and real-time integration for your mission-critical data. It is described in more detail in Section 3.7.1.
Oracle Streams is also a very flexible and powerful database replication feature that Oracle will continue to support but will not make major enhancements in future releases.(Oracle 在Stream 上不会在投入太多了) You can continue to use an existing Oracle Streams deployment to maximize your return on investment. However, you should consider Oracle GoldenGate as the long-term replication strategy for your organization. See the Oracle Database 2 Day + Data Replication and Integration Guide, Oracle Streams Concepts and Administration, and the Oracle Streams Replication Administrator's Guide for more information about Oracle Streams data replication and integration.
Oracle GoldenGate will be enhanced with many of the best capabilities of Oracle Streams to create a best-of-both worlds information distribution solution.
3.7.1 About Oracle GoldenGate
Oracle GoldenGate is an asynchronous, log-based, real-time data replication product that moves high volumes of transactional data in real-time across heterogeneous database, hardware, and operating system environments with minimal impact.
A typical environment includes a capture, pump and delivery process. Each of these processes can run on most of the popular operating systems and databases, including Oracle Database and non-Oracle databases. All or a portion of the data may be replicated, and the data within any of these processes may be manipulated for not only heterogeneous environments but also different database schemas. Oracle GoldenGate supports multimaster replication, hub-and-spoke deployment, and data transformation. Thus, Oracle GoldenGate enables you to ensure that your critical systems are operational 24/7, and the associated data is distributed across the enterprise to optimize decision making.
Oracle GoldenGate is also an excellent method to minimize downtime during planned maintenance, including application and database upgrades, in addition to platform migrations.
Benefits of Oracle GoldenGate
Oracle GoldenGate optimizes real-time information access and availability because it:
（1）Supports replication involving a heterogeneous mix of Oracle Database and non-Oracle databases
（2）Maintains conti