Introduction

Oracle GoldenGate Extract, Replicat and associated utilities enable you to create, load and refresh one database to another database.  This white paper will be utilizing examples for Oracle to Oracle homogenous replication, but it does not preclude the source and target environments being heterogeneous databases.   These examples also show data being replicated between a Cloud and On-Premise environment.  The example environments can easily be reversed to be replication between On-Premise and a Cloud environment.  It depends on your specific requirements.

Main Article

This document will address different approaches to extracting data from a Cloud environment and replicating it to an On-premise environment.

Cloud to On-Premise using a Mid-Tier:

In this approach, a mid-tier is utilized to eliminate the requirement of the cloud or on-premise environment to have a direct connection into either environment. Only the mid-tier allows a direct network connection to specific ports defined by the PORT and DYNAMICPORTLIST parameters in the manager parameter file, or connect through SSH SOCKS Proxy tunneling via the use of OGG enhanced cloud support parameter SOCKSPROXY.

Cloud to On-Premise utilizing a Passive Extract Pump:

In this approach, the cloud environment is allowing a connection to very specific ports from the trusted on-premise environment. The data is extracted from the cloud database with a standard extract, but the data is pushed to the on-premise environment using a Passive extract pump. The passive extract pump is stopped and started from the on-premise environment. The connection to the passive extract pump is initiated by the On-Premise environment in one of two ways. The first option is to use specific trusted ports defined by the PORT and DYNAMICPORTLIST parameters in the manager parameter file. The second option is to use SSH SOCKS Proxy tunneling, which uses SSH Port (22) in the OGG cloud environment; the trusted On-Premise environment tunnels into the connection via the use of the OGG enhanced cloud support parameter SOCKSPROXY.

Cloud to On-Premise utilizing a Passive Extract:

In this approach, the cloud environment is allowing a connection to very specific ports from the trusted on-premise environment. The data is extracted from the cloud database with a passive extract.. The passive extract is stopped and started from the on-premise environment. The connection to the passive extract is initiated by the On-Premise environment in one of two ways. The first option is to use specific trusted ports defined by the PORT and DYNAMICPORTLIST parameters in the manager parameter file. The second option is to use SSH SOCKS Proxy tunneling, which uses SSH Port (22) in the OGG cloud environment; the trusted On-Premise environment tunnels into the connection via the use of the OGG enhanced cloud support parameter SOCKSPROXY. The caveat with this approach is that if the network connection goes down, the extract process will abend. As a result, data will not be extracted until the connection is restored.

Extract, Extract pump and Replicat work together to keep the databases in sync near real-time via incremental transaction replication.  In all examples this function is accomplished by
1)  Starting the Manager program in all OGG installed systems.
2)  Adding supplemental transaction log data for update operations on the source system.
3)  Running the real-time Extract to retrieve and store the incremental changed data from the Oracle tables into trail files on the target Unix system.
In the first 2 approaches, running the real-time Passive Extract pump to send incremental changed data from the cloud environment or the mid-tier to the target on-premise system.

After initial synchronization,
4)  Start the real-time Replicat to replicate extracted data.

Once Extract and Replicat are running, changes are replicated perpetually.

Summary

Hopefully, this white paper has provided a quick overview of what options you can utilize to replicate data between the cloud to on-premise environments.  Undoubtedly, you will eventually fine-tune this process in your own environment.
Reference the Oracle Database 12.1 Documentation for additional information on the Oracle 12.1 RDBMS.
Reference the Oracle GoldenGate 12c Reference Guide and the Oracle GoldenGate 12c  Administration Guide for additional information on:

Extract Parameters for Windows and Unix
Replicat Parameters for Windows and Unix
Passive Extract for Windows and Unix
Extract Management Considerations
Replicat Management Considerations

Download:

Oracle Support Document 1996653.1 – Oracle GoldenGate Best Practices: Replication between Cloud and On-Premise Environments with Oracle GoldenGate

Do you have any questions or would like to hear more about Oracle GoldenGate Best Practices in Cloud? Please take a minute to provide your feedback here

All content listed on this page is the property of Oracle Corp. Redistribution not allowed without written permission