Introduction to Golden Gate

In 2009, Oracle acquired Golden Gate to strengthen its data replication technology as part of future strategies within data warehouse and real time transaction database. Before this acquisition, Oracle  had its own replication technology which mainly constitutes basic replication, advance replication and stream replication.

Oracle's basic replication process had two different methods: log based and trigger based. In log based replication, snapshot schema and DB links had to set up between source and target database. Data was transported from online redo log to target database over network.

In advance replication Oracle included multiple master replications from multiple environments and trigger based replication method.

In later versions of Oracle 9i, stream replication was introduced with improvements in its earlier replication technologies. It uses log based replication where committed transaction’s online redo log of source system is mined to target system over network. Also a new background process to manage communication and operations of replication activities has been introduced

However these replication technologies couldn't stand long as it involved complicacy and complex software development to harness the power of Oracle to Non Oracle database environment to allow the transaction to be moved between environment.

In 1990, a small software company Golden Gate came with different approach on data replication between cross platform. Instead of using different formats, Golden Gate implemented a uniform format and used a command prompt GGSCI (Golden Gate Software Command Interface) to perform data replication operation. Oracle Goldengate 11g supports both DDL and DML operation. Legacy Oracle 8i version or prior requires an upgrade to 9i or later to implement the Goldengate.

Goldengate supports all popular databases such as Oracle, MySQL, DB2, Sybase, Teradata, SQL server etc.

Goldengate contains three installable components which can be downloaded separately from Oracle's website and can be installed on both, source and target system depending on requirement. Below is the list of installable components for Goldengate:

•  Oracle Goldengate which includes GGSCI, DEFGEN, LOGDUMP and REVERSE.
• Oracle Goldengate Director which includes Director Service application, Monitor Agent, Director Client and Administrator client.
• Oracle Goldengate Veridata which includes Agent, CLI, Web interface.

 Architecture

Manager Process

• Start and manage Goldengate processes such as collector.
• Manage port numbers.
• Trail Management.
• Create  error, event and reports.
• Process command GGSCI.

Extract Process – Extract DML and DDL data from source database. 

Data Pump Process: Option process but recommended. Read records from source trails, process them and passes over to target system.

Collector Process: This background process runs on Target system.  It writes records on remote trail.

Replicate Process: Reads Remote trail, process them and applies changes to target Database.

Trail: It is a Goldengate intermittent file written in proprietary format by either extract process (source system) or collector background process (target system).