Differences between Oracle Advanced Replication, stream replication, and slave Database

Oracle backup features include:

Advanced Replication)

Streaming Replication)

Slave uard)

One worker uard:

Dataguard is generally the first choice for DBA in terms of high availability and Disaster Tolerance. After all, dataguard has an overwhelming advantage in this regard, whether it is a physical standby database (physical standby database) or the logical standby database, which all have some common features to be levied.

Configuration and management costs: replica uard is simpler and more convenient than stream replication; security and stability costs: replica uard is more stable and reliable than stream replication.

For a 24x7 system, these are very important. The increase in system downtime not only affects the company's image, but also the company's benefits. The adoption of dataguard, data security is quite guaranteed. The physical standby database can complete failover in the shortest time, while ensuring data security, the logical standby database can also undertake a large number of reports and other services; because the configuration and management of dataguard are relatively simple, the DBA's work intensity is also reduced;

Second-stream replication:

Applicable to the following situations:

1. Partial replication stream can only replicate certain tables or certain modes

2. Fully utilize existing devices and technologies in heterogeneous environments

3. Remote Disaster Recovery stream has lower network requirements than mongouard

Stream replication has a flexible replication policy, which not only allows you to copy only some tables, but also allows you to copy only the DDL or DML of some tables. Compared with replica uard, you must copy the entire database, this can save considerable Storage Investment. After all, many of the massive data volumes do not need to be copied.

If it is in a heterogeneous environment, that is, different operating systems, then the replica uard will be helpless, and non-stream replication will not belong, so that you can make full use of the existing environment, configure high-availability solutions, in a heterogeneous environment, stream replication will be a strong competitor of advanced replication.

Stream replication transmits the logical change records (LCRs) that are mined and packaged by logmnr. Compared with the archived redo log transmitted by mongouard, The mview log of Advanced Replication and the mview refresh method, stream replication reduces network requirements a lot. In the remote Remote Disaster Recovery Process, renting network bandwidth is a high cost, and stream replication can appropriately reduce this cost.

Iii. Advanced Replication:

Compared with replicuard, Advanced Replication has the following Disadvantages: complicated configuration and management, insufficient security and stability; advantages: Local replication and heterogeneous environments. Advanced Replication is a very mature technology that has been successfully applied in many key systems. Compared with stream replication launched by 9ir2, both parties are applicable in a similar environment, for example, local replication, heterogeneous replication, and Remote Disaster Tolerance can all be performed. Advanced Replication is now able to withstand the test of stability and security.

Compared with the underlying implementation technologies of stream replication and advanced replication, stream replication has more advantages in real-time, stability, high efficiency, and low consumption (less CPU/network resources, however, there are more or less uncertain factors in some new features.

In 10gr1, Oracle has enhanced the weakness of stream replication. It not only provides scripts for migrating data from advanced replication to stream replication, but also provides configuration and monitoring tools for stream replication, stream replication will be intelligent and simple in terms of configuration and management, and it will take the responsibility of competing with shareplex for the enterprise data replication market.

Iv. Differences between Advanced Replication and stream Replication

The principles of Advanced Replication and streams replication are completely different. Streams replication can be used at the table, user, and database level, but Advanced Replication can only be performed at the table level.

Streams replication is not an upgraded version of advanced replication.

In heterogeneous environments, there are two types of high availability and Disaster Tolerance for Oracle: Advanced Replication and stream replication. The two types of similarities and differences are as follows:

1. Advanced Replication is based on trigger principles, while stream is based on log mining principles. Therefore, stream replication has less impact on the performance of the source database, but its real-time performance is inferior to advanced replication.

2. the objects of Advanced Replication are based on database objects, such as tables, indexes, and stored procedures. Stream replication can target tables, schemas, and the entire database, therefore, for disaster tolerance, the configuration of stream replication is relatively simple.

3. advanced Replication is a mature technology that has been successfully applied in many key systems. Compared with stream replication launched by 9ir2, Advanced Replication is now more stable and secure.

4. from the perspective of development, there will be more and more stream applications. From Oracle10g, Oracle provides a tool for migrating from advanced replication to stream replication. We can see that, oracle will focus more on new stream-based technologies.

5. because Advanced Replication is based on triggers, all changes to the replication object structure (DDL) must be implemented through the copy package provided by Oracle, Which is tightly integrated with applications, it is more suitable for developers, while stream replication is more suitable for DBAs.

6. Streaming replication supports two-way data replication, while Advanced Replication conflicts;

7. Stream replication supports Heterogeneous Database Replication. If no information is provided, Advanced Replication also has the same function;

In actual use, streams replication requires less bandwidth and 2 Mbit/s bandwidth. If streams replication does not work, Advanced Replication is probably useless, but it is best not to use streams for too long network disconnection, I don't know if it's a bug or Oracle. If the replication stops for a while and then returns to normal, it's probably because there are too many messages in the queue table, and the team is very slow and non-linear growth, this requires a short period of time for data synchronization, and Advanced Replication does not.

Bug. There are some bugs in, and. It seems that you cannot touch it. It means that you can delete the team list and recreate it. This means that the entire copy is rebuilt, however, if you want to repeat it, it will not appear; if you want to use negative rule, the speed of a large update transaction will become extremely slow. If there are more sites, you must first design the structure; the TRC file will not be generated in the udump directory of the site with the apply process. Although it is not very mature, streams replication is really good. It will definitely replace Advanced Replication in the future. We recommend you install the 10.2.0.3 patch, it is said that many bugs have been fixed.

Stream must have considerable control over stream technology for system design and maintenance. However, most systems have no experience with DBAs, so it is difficult to promote them; dataguard is easy to maintain and reliable, and can be maintained by common DBAs. Stream will be very promising in the future! In particular, bidirectional replication solves many practical problems.