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Oracle® Application Server CDC Adapters for IMS/DB User's Guide
11g Release 1 (11.1.1)

Part Number E16092-01
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1 Introduction

Change data capture (CDC) is an integration technology that enables efficient near real-time integration by capturing changes made to enterprise data sources and providing them for processing in integration middleware, such as Oracle Fusion Middleware. The CDC Adapter can be used by Oracle SOA Suite (BPEL Process Manager, Oracle Enterprise Service Bus) and Oracle Data Integrator (ODI).

The OracleAS CDC Adapter for IMS/DB, captures changed IMS/DB segments that are passed to the DFSFLGX0 IMS user exit, and saves them in an MVS logstream. The IMS/DB CDC Agent polls the logstream for the changes.

OracleAS CDC Adapter OracleAS CDC Adapter

This chapter provides an overview of the features and architecture of the OracleAS CDC Adapter for IMS/DB. It includes the following topics:

OracleAS CDC Adapter for IMS/DB Overview

The OracleAS CDC Adapter for IMS/DB captures and delivers changes (such as insert, update, and delete operations) made to data in IMS/DB data sources. By using the CDC Adapter, you can build efficient data integration solutions that use IMS/DB data, synchronize systems to ensure data integrity, update data warehouses and operational data stores in near real-time, and enable event-driven business activity monitoring and processing.

The OracleAS CDC Adapter for IMS/DB has the following capabilities:

Using the OracleAS CDC Adapter for IMS/DB makes ETL (extract, transform, and load) processes more efficient and less disruptive to the operation of the source database systems, eliminating the need for the traditional ETL downtime window.

OracleAS CDC Adapter for IMS/DB Architecture

The following figure illustrates the system components used for change data capture using the OracleAS CDC Adapter for IMS/DB.

Figure 1-1 Component Architecture used with the IMS/DB CDC adapter

Architecture of the Oracle CDC Agent for IMS/DB.
Description of "Figure 1-1 Component Architecture used with the IMS/DB CDC adapter"

The OracleAS CDC Adapter for IMS/DB component architecture includes the following components:

The Staging Area

The staging area is an area used by Oracle Connect to store captured data from a journal. The journal is scanned once and changes for every required table read during that scan are passed to the staging area, where they are stored. Therefore, the journal is scanned once each time it is polled. After the changes are written to the staging area, processing of these changes is carried out independently of the journal.

The staging area is a benefit when transactions are used. The changed data is not written to the change queue until the transaction is committed. Thus, if the transaction fails, there is no overhead of having to back out any processing done with the steps in the failed transaction.

The staging area can be on any computer with a Windows, Linux, or UNIX operating system that is running the Oracle Application Server and does not need to be run on the same server as the IMS/DB CDC adapter. Once the information is extracted from the journal and written to the staging area, processing of changes is carried out on the staging area only. Thus, the staging area should be set up to consider the network configuration and where the consumer application runs.

The staging area maintains the last position read by the consumer application (the staging area context) and starts at this point the next time a request from the consumer application is received. The context is stored in the repository where the staging area is maintained.

The staging area is indexed so that access to the staging area for a specific stream is quick.

The staging area is automatically cleared every 48 hours. All events that have been in the staging area for more than 48 hours are deleted.