DBA_Oracle GoldenGate introduction (concept), oraclegoldengate

DBA_Oracle GoldenGate introduction (concept), oraclegoldengate

2014-09-12 BaoXinjian

I. Summary

GoldenGate is a log-Based Structured Data replication software. It parses online logs of the source database or archives logs to obtain incremental data changes and then applies these changes to the target database, to synchronize the source and target databases.

GoldenGate can achieve sub-second-level real-time replication of large amounts of data between heterogeneous IT infrastructure (including almost all common operating system platforms and database platforms, it can be used in emergency systems, online reports, real-time data warehouse supply, Transaction Tracking, data synchronization, centralized/distributed, Disaster Tolerance, and other scenarios.

 

At the same time, GoldenGate can implement one-to-one, broadcast (one-to-multiple), aggregation (Multiple-to-one), bidirectional, point-to-point, cascading, and other flexible topology structures.

 

1. Advantages:

• 1. simple installation and configuration.
• 2. The Management and maintenance are relatively intuitive. the built-in Oracle Management Pack for Oracle GoldenGate Management tool allows you to manage its graphical interface.
• 3. supporting heterogeneous replication, such as the replication of different users and different database platforms, is also a highlight.
• 4. The future development potential is still very promising.

2. Disadvantages:

• 1. The official software currently only supports 64-bit systems.
• 2. because it is a third-party tool, it has high requirements on the environment, especially in the LINUX environment, it has requirements on the character set of the operating system, mainly because the table names in our system are all Chinese, must support Chinese characters.
• 3. during parameter configuration of the application process, it is found that for a large number of table copies, it is not clear whether GoldenGate has restrictions, because at startup, when I configure parameters to copy all ZLHIS tables, the error "" will be prompted. However, if you only copy a few or a single table, this prompt will not appear, the problem is being verified.
• 4. Currently, the information available on the Internet is quite limited, and the penetration rate is not very high.

3. to sum up, the highlights of GoldenGate compared with stream replication are still heterogeneous. However, the official Oracle statement is that the first-class Streams technology will be integrated into GoldenGate in the future, this is also its development trend. Its value is worth further research for our users' applications.

 

 

 

Ii. Analysis

1. OGG is a data synchronization software, or logic replication software. Its competitors include ibm cdc, DELL shareplex, DSG, and DDS.

2. OGG software must be installed on the operating system. Oracle DB software does not have its own OGG software (at least currently)

3. The OGG software has three major processes (the four major processes can also be said ):

• Three processes: Source extraction process, source transmission process, and target application process (namely, replication process)
• Four processes: the source extraction process, the source transmission process, the target server process (responsible for writing the trail file to the target), and the target application process (namely, the replication process)

4. OGG software has two types of trail file

• Source trail file: written by the source extraction process.
• Destination trail file: the source transmission process is transmitted to the destination, and the destination server process is written to the specified path of the destination operating system.

5. All three processes in OGG software have their own checkpoints (I .e., checkpoints are used to record the locations where each process reads and writes)

• Source extraction process: there are read and write checkpoints
• Source transmission process: there are read and write checkpoints
• Target application process: there is a read checkpoint

6. Three major OGG software processes the trail file:

• Source extraction process: Read the oracle redo log (assuming that the source database is oracle), and convert the content in the redo log into a file in OGG's own format (I .e: and write it to the specified path of the source operating system.
• Source transmission process: read "The trail file written by the source extraction process", send the data to be synchronized to the target end in combination with the parameter file of the transmission process, the server process is responsible for writing data to the target end.
• Target application process: Read the trail file in the specified path of the target operating system, combine the parameter files of the application process to form SQL statements, and execute these SQL statements on the target database.

7. OGG System Structure

8. OGG can cope with Data Maintenance

 

********************Author: Bao Xin********************

Error Message
What does goldengate mean?

Goldengate (oracle goldengate for short) is a company acquired by oracle a few years ago to replicate databases. The biggest advantage of OGG is that it can be replicated between different databases, which is easy to configure, efficient and easy to use.