SAP Replication Server Overview

Data Replication is a process that copying data from a database to another databases.

SAP Replication Server uses to get real-time data updates.

SAP RS can replicate data not only from/to ASE databases (also ORACLE, SQL SERVER, etc.).

SAP RS can be installed and run on Windows and Linux.

Replication is

• From a primary (= source) database [one primary database].
• To one or more replicate (= target) databases [one or more replicate databases].

RS can replicate one or more tables from the primary database. That means that not all the DB has to be full replicated, and in the other hand not only one object.

RS main terms

Replication definition

Describes the structure of what we replicate.

In order to publish and subscribe data, we first need to create a replication definition to designate the scope and location of the primary data.

In the Replication definition we declared exactly what we want to replicate:

• DML/DDL
• Which table/s
• What in the table:
• Columns
• Data (where salary > 1000 )
• etc.

Publication

We “publish” data at primary sites …

Subscription

… to which Replication Servers at other sites “subscribe.”

* Creating a replication definition does not, by itself, cause Replication Server to replicate data. 

We must also create a subscription against the replication definition to instruct Replication Server to replicate the data in another database.

LTM (LTM locator)

A “locator” value that is used to identify the last point in a transaction log from which all data has been successfully received by the primary Replication Server.

Related to the RepAgent.

Connection

Connection exists between RS and the databases it manage (RS databases - One Primary database, One or more Replicate databases).

A Replication thread DSI uses this connections to send updates to the replicate database.

RSSD – Replication Server System Database

Used for RS to save some definitions and configurations.

Can be in any SAP ASE instance (not must to be on the server where the RS is installed).

System tables include:

• Descriptions of replicated data and related information.
• Security records for Replication Server users.
• Routing information for other sites.
• Access methods for the local databases.
• Other administrative information.

sql.ini

Server Entries definitions.

In Linux OS is "interfaces" file instead of sql.ini.