Oracle Goldengate - barialim/architecture GitHub Wiki
Overview
Oracle GoldenGate is a software product that allows you to replicate, filter, and transform data from one database to another database.
Why do you need Oracle goldengate?
Enterprise data is typically distributed across the enterprise in heterogeneous databases. To get data between different data sources, you can use Oracle GoldenGate to load, distribute, and filter transactions within your enterprise in real-time and enable migrations between different databases in near zero-downtime. See here for more info.
Why do you use Oracle goldengate?
Oracle GoldenGate meets almost any data movement requirements you might have. Some of the most common use cases are described in this section.
How do you use Oracle goldengate?
See here for more info.
Data Guard
Oracle Data Guard is a solution that helps to ensure business continuity by minimizing the various kinds of planned and unplanned downtime that can affect their businesses.
Oracle Data Guard is a management, monitoring, and automation software infrastructure that works with a production database and one or more standby databases to protect your data against failures, errors, and corruptions that might otherwise destroy your database.
It automates the process of maintaining a copy of an Oracle production database (called a standby database) that can be used if the production database is taken offline for routine maintenance or becomes damaged or unavailable in the event of disaster.
Architecture
It works with a Primary production database and one or more stand-by databases to protect your data against failures in the event of disaster. A standby database is a synchronized copy of the primary database. By using a backup copy of the primary database, you can create 1-9 standby databases.
The standby databases, together with the primary database, make up a Data Guard configuration. All Data Guard standby databases can enable up-to-date read access to the standby database while redo being received from the primary database is applied using Log Apply service.
Type of Stand-by Databases
A standby database is a transactionally consistent copy of the primary database. Using a backup copy of the primary database, you can create up to nine standby databases and incorporate them in a Data Guard configuration. Once created, Data Guard automatically maintains each standby database by transmitting redo data from the primary database and then applying the redo to the standby database.
A standby database can be either a physical standby database or a logical standby database:
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Physical standby database
Provides a physically identical copy of the primary database, with on disk database structures that are identical to the primary database on a block-for-block basis. The database schema, including indexes, are the same. A physical standby database is kept synchronized with the primary database, through Log Apply service called Redo Apply, which recovers the redo data received from the primary database and applies the redo to the physical standby database.
A physical standby database can be used for business purposes other than disaster recovery on a limited basis.
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Logical standby database
Contains the same logical information as the production database, although the physical organization and structure of the data can be different. The logical standby database is kept synchronized with the primary database through Log Apply service called SQL Apply, which transforms the data in the redo received from the primary database into SQL statements and then executing the SQL statements on the standby database.
A logical standby database can be used for other business purposes in addition to disaster recovery requirements. This allows users to access a logical standby database for queries and reporting purposes at any time. Also, using a logical standby database, you can upgrade Oracle Database software and patch sets with almost no downtime. Thus, a logical standby database can be used concurrently for data protection, reporting, and database upgrades.