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Enterprise Connect 12.0 Integrated Product Sets Overview Guide |
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| Chapter 3 Enterprise Connect Data Movement |
Chapter 3
This chapter describes Enterprise Connect Data Movement components.
Enterprise Connect Data Movement is the enterprise solution for capturing and delivering database changes in a heterogeneous Sybase and non-Sybase data server environment. Sybase Replication Agent pulls database changes from non-Sybase data sources as Informix, Microsoft SQL Server and Oracle and supplies them to Replication Server. Replication Server delivers these changes throughout the enterprise.
Enterprise Connect Data Movement includes:
Replication Server, which provides Log Based, bi-directional replication of distributed data for reliable delivery of transactions
Sybase Adaptive Server Enterprise (ASE) with restricted license for Replication Server System Database (RSSD)
Sybase Replication Agent, which extends the capabilities of Sybase Replication Server to non-Sybase data including Oracle, Informix and Microsoft SQL Server
Replication Server is an Open Server application that maintains replicated data in multiple databases while ensuring the integrity and consistency of the data. It provides client applications with local data access, thereby reducing load on the network and centralized computer systems.
Replication Server supports heterogeneous data servers. You can build a replication system from existing databases and applications and, as your enterprise grows and changes, you can add data servers and Replication Servers to accommodate your evolving business needs.
With Replication Server you can:
Maintain a warm standby copy of a primary database so that, if the primary system fails, clients can switch to the standby copy almost immediately.
Replicate an online transaction processing (OLTP) database to a decision-support database, to run decision-support queries in near real time, without affecting OLTP performance.
Synchronize databases with different schemas, formats, and naming conventions.
Replicate the execution of stored procedures from one database to another.
Continue to work even if some system components are unavailable. Replication Server saves transactions in stable queues that allow databases to re-synchronize without losing information.
Manage your Replication Servers and your replication system using the Sybase Central graphical interface.
Replication Server can replicate to a single database, to multiple databases, or to other Replication Servers in a complex replication system.
Replication Server guarantees transaction delivery; every transaction successfully received from a Replication Agent is guaranteed to be delivered to appropriately subscribing replicate databases.
The replication system administrator creates subscriptions for replication definitions on Replication Server. Replication definitions specify the data that is obtained from the primary database and subscriptions specify where to send the data. Replication definitions are stored in the RSSD of the primary Replication Server.
The replication system administrator also defines database connections and replication routes to manage the replication system.
Replication Server stores all these types of replication system data (replication definitions, subscriptions, connections, and routes) in the Replication Server System Database (RSSD), which is a database dedicated for this use by Replication Server.
The Replication Server plug-in for Sybase Central, Replication Server Manager, lets you create a replication system domain in which you can include and manage all or a part of the data servers, Replication Servers, and Replication Agents in your business Enterprise, including non-ASE servers.
Replication Server Manager is a Sybase Central-based graphical user interface (GUI) systems management tool for administering servers in a replication system. It runs within the Sybase systems management framework, Sybase Central. Replication Server Manager runs on Windows 98 or Windows NT.
Sybase Central displays a topological view of your domain that includes routes, connections, and replication agents as well as data servers and Replication Servers.
From Sybase Central, you can display and manage most aspects of your replication system without entering RCL commands or stored procedure syntax.
For example, you can:
Create and manage replication definitions, publications, and subscriptions
Organize your replication system for convenient monitoring and managing
Display and manage information about Replication Server, Replication Server Manager, and Replication Agent users
Display status information for replication system objects, including servers, connections, routes, threads, and users
Add or delete connections and routes
Resume or suspend connections and routes
Display properties of tables, queues, partitions, threads, and function-string classes
Generate DDL for replication scripts
With the support of Sybase Replication Agents and Sybase DirectConnects, Replication Server Manager lets you manage some of the heterogeneous, non-ASE data servers in your replication environment, including Informix, Oracle, and Microsoft SQL Server.
Sybase Replication Agent is the Enterprise Connect Data Movement component that captures transactions in the primary database and then transfers transactions to Replication Server for distribution to replicate databases.
Sybase Replication Agent extends the capabilities of Replication Server by allowing non-Sybase database servers to be primary data servers in a Sybase replication system.
Enterprise Connect Data Movement enables you to configure Sybase Replication Agent as follows:
Replication Agent for Informix - retrieves transactions from an Informix primary database
Replication Agent for Oracle - retrieves transactions from an Oracle primary database
Replication Agent for Microsoft SQL Server - retrieves transactions from a Microsoft SQL Server primary database
Sybase Replication Agent consists of a set of components that work together to perform all the operations required to propagate transactions from a primary database for replication.
The main Replication Agent components and their functions are:
Log Reader -- Reads the transaction log in the primary database to retrieve transactions for replication.
Log Transfer Interface (LTI) -- Generates Log Transfer Language (LTL) and sends it to the primary Replication Server.
Log Administrator -- Administers the transaction log and manages transaction log objects.
Log Transfer Manager (LTM) -- Manages all the other components and coordinates their operations for replication.
In addition to the four main components, Replication Agent has an administration port that provides an administrative user interface.
Sybase Replication Agent uses a transaction log that records copies of the transactions (or procedure invocations) to be replicated. The Log Reader component of Replication Agent reads the transaction log to retrieve the transaction from the primary database.
After the transaction is retrieved from the primary database, the Log Transfer Interface (LTI) component of Replication Agent processes the transaction and the resulting "change set" data and generates LTL output, which Replication Server will use to distribute the transaction to the subscribing replicate database(s).
Sybase Replication Agent runs as a stand-alone application, independent of the primary database server, the primary Replication Server, and any other components of a replication system.
Sybase Replication Agent can reside on the same host machine as the primary database or any other component of the replication system, or it can reside on a separate machine from any other replication system components.
Sybase Replication Agent is compatible with Replication Server Manager (RSM), and Replication Agent instances can be configured, managed, and monitored by RSM. In addition, you can completely configure, manage, and monitor a Replication Agent instance using any Open Client application that is capable of communicating with the Sybase Tabular Data Stream (TDS) protocol (such as isql).
While replicating transactions, Replication Agent maintains connections with both the primary database and the primary Replication Server. In addition, Replication Agent occasionally connects to the RSSD of the primary Replication Server to retrieve replication definition data.
Adaptive Server Enterprise (ASE) is included in Enterprise Connect Data Movement. It is licensed solely to be the repository for the Replication Server System Database (RSSD).
Replication Server stores replication definitions, subscriptions, routes, and other important information in the RSSD.
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