Data Replication Architecture for Integrating Heterogeneous Systems with Oracle Databases
As stated in my previous post, in a replication system using SAP Sybase Replication Server an Oracle database can be either a source or a destination database for data replication. In this post, I’d like to describe an architecture employing Oracle databases as source and destination databases in a SAP Sybase replication environment. My initial focus, however, will be on the scenario where Oracle is the source of primary data i.e. Oracle is the source database. I will also detail an example configuration process for creating a replication system featuring Oracle 11 and ASE 15.7 as source and target or destination databases respectively. I will also share a how-to-video that demonstrates all the technical steps involved in standing up the system.
In order for Oracle to participate as a source database in a SAP Sybase replication system, we need a separate component called Replication Agent for Oracle (RAO) to read from an Oracle transaction log. Likewise, in order for Oracle to participate as a destination database, we need a connectivity module to access Oracle. We have a couple of implementation options as below:
- In Pre 15.5 Replication Server versions, we have to configure a separate server component called Direct Connect for Oracle as shown below:
- In Replication Server 15.5 and later a module called Express Connect for Oracle is shipped with Replication Server, hence eliminating the need to have a separate process to communicate with the destination database. This is illustrated below:
Adding a destination Oracle database in a SAP Sybase Replication Server system is really simple with Replication Server version 15.5 and later, but adding a source Oracle database is more complex because we have to create, start and configure a new RAO instance.
Configuring Replication from ORACLE 11 to ASE 15.7 with Replication Server 15.7
In the how-to-video below, I go through the steps for establishing a replication system replicating from Oracle 11 to ASE 15.7 using SAP Sybase Replication Server. The prerequisites are:
- Oracle 11 instance running with a schema that will have primary tables.
- ASE 15.7 instance running with a database that will contain replicate tables.
- 2 users created in the Oracle instance, one will be used by RAO and the other one by ECO (in this case called maintenance user). Check RAO manuals (link below) for specific permissions for these users ❗
- Create the connection to the ASE database (rs_init)
- Create the connection to the Oracle database (manually with create connection command). Note that:
- Oracle has to be configured for archiving or redo logs and supplemental logging of primary key and unique index data
- Install Oracle instant client
- Add Oracle instance to tnsnames.ora file
- Create the new RAO instance and start it:
- Add the new instance to interfaces file
- Create the instance with “administrator” utility
- Before starting the RAO server, be sure that both Oracle and Sybase jdbc drivers are included in the CLASSPATH
- Configure new RAO parameters
- Check that RAO is able to connect to RSSD, primary database and Replication Server
- Initialize new RAO instance
- Mark tables at primary, resume instance and create replication definitions/subscriptions
I hope this post helps anyone who wants to start using Oracle as a primary database in an SAP Sybase Replication Server system. More interesting discussions on the topic of heterogeneous replication will be featured in upcoming blog posts wherein I will also address the following questions:
- How can we configure other primary data sources, for example MSSQL Server ?
- Is Hana going to be certified with SAP Sybase Replication Server ?
More details in SAP Sybase documentation:
- “Heterogeneous Replication Guide“
- “Replication Agent Administration Guide“
- “Replication Agent Primary Database Guide for Oracle“
- Follow the “Database Services Content Library” to access the entire series of Database Services Blogs and join the conversation on Twitter @SAPServices
- Learn more about SAP Database Services here “http://www.sap.com/services-and-support/data-and-technology/database-services.epx“