CDC Guide for Linux, UNIX, and Windows

10.5
- 10.5.6
- 10.5.5
- 10.5.4
- 10.5.3
- 10.5.2
- 10.5.1
- 10.4.1
- 10.4.0 HotFix 1
- 10.4.0

Back Next

PowerExchange Express CDC for Oracle Architecture

Example configurations demonstrate the general PowerExchange Express CDC for Oracle architecture.

The configurations include the following components:

Oracle source tables and redo logs

PowerExchange Express CDC capture components, including the log reader

PowerExchange Listener

PowerExchange Logger for Linux, UNIX, and Windows, which is optional but strongly recommended

PowerExchange Navigator

PowerCenter and the PowerExchange Client for PowerCenter (PWXPC)

PowerExchange Express CDC for Oracle does not use the PowerExchange UOW Cleanser.

Configuration 1: All Capture Components on the Oracle System

If you have a Linux, UNIX, or Windows system that has sufficient CPUs and disk space, Informatica recommends that you run the Oracle instance, Oracle Express change capture components, PowerExchange Listener, and PowerExchange Logger all on that system. The PowerExchange Logger log files reside on the same system. This configuration avoids network-related degradation of performance and is the easiest one to configure and maintain.

The following figure shows Configuration 1:

The Express CDC log reader reads change records directly from the Oracle redo logs and forwards the committed changes to the PowerExchange Logger. The PowerExchange Logger logs the changes to its local log files. When a PowerCenter CDC session runs, change data is pulled from the PowerExchange Logger log files and sent to target tables, which are usually on a different system. Besides handling requests for change data, the PowerExchange Listener handles PowerExchange Navigator and PWXPC requests for Oracle metadata or data, registrations, and extraction maps for other functions such as database row tests.

With this configuration, the PowerExchange Express CDC system contains the PowerExchange Express CDC for Oracle configuration file, the PowerExchange Logger configuration file, and the dbmover.cfg configuration file. The dbmover.cfg file includes the ORAD CAPI_CONNECTION, CAPX CAPI_CONNECTION, ORACLEID, and ORACLE_CAPTURE_TYPE statements. The dbmover.cfg file also includes the CAPX CAPI_CONNECTION if you use continuous extraction mode.

Configuration 2: PowerExchange Express CDC in a RAC Environment Without ASM

If you want to capture change data in an Oracle RAC environment, Informatica recommends that you run the PowerExchange Express CDC capture process and PowerExchange Logger on a server outside of the RAC. With this configuration, if a RAC member node fails, Express CDC continues running, and Oracle establishes a connection to another active RAC member node.

In this configuration, the Express CDC log reader still reads change records directly from the Oracle redo logs and forwards the committed changes to the PowerExchange Logger. The archived and online redo logs must exist on a shared disk that can be accessed from the server where the PowerExchange Logger runs. The PowerExchange Logger logs the changes to its local log files. When PowerCenter CDC sessions run, PWXPC extracts changes from these log files.

To read change data, the PowerExchange Express CDC log reader must run under a user ID and password that has read access to the online and archived redo logs. Also, the Oracle Client must run under a user ID and password that has been granted SELECT authority on the appropriate database objects, as described in the PowerExchange ora_orad.sql file.

The following figure shows a RAC with two member nodes and a separate Linux system with the PowerExchange Express CDC capture process and PowerExchange Logger:

The two RAC nodes write data to the Oracle redo logs. The Express CDC capture process that runs on the Linux system reads change data from the redo logs.

The PowerExchange Listener also runs on the Linux system.

In this scenario, a tnsnames.ora file resides on the Linux system. It specifies the FAILOVER option and the following connection descriptor that allows connection to either RAC member node:

ORATEST2=
  (DESCRIPTION=
    (FAILOVER=ON)
    (ADDRESS_LIST=
      (ADDRESS=(PROTOCOL=TCP)(HOST=rclnxrac21.informatica.com)(PORT=1521))
      (ADDRESS=(PROTOCOL=TCP)(HOST=rclnxrac22.informatica.com)(PORT=1521))
    )
    (CONNECT_DATA=
      (SERVICE_NAME=ORATEST2.informatica.com)
    )
  )

The following PowerExchange files also reside on the Linux system:

CCT, CDEP, and CDCT files

PowerExchange Logger log files

PowerExchange Express CDC for Oracle configuration file

A dbmover.cfg configuration file that includes the ORAD CAPI_CONNECTION, CAPX CAPI_CONNECTION, ORACLEID, and ORACLE_CAPTURE_TYPE statements

In the PowerExchange Express CDC for Oracle configuration file, you must specify the following statement for CDC in a RAC:

RAC MEMBERS=2;

The MEMBERS parameter specifies the maximum number of redo log threads that PowerExchange Express CDC for Oracle can track for member instances in the RAC, including open and closed threads.

Configuration 3: PowerExchange Express CDC in a RAC Environment with ASM

If you want to capture change data in an Oracle RAC environment, Informatica recommends that you run the PowerExchange Express CDC capture process and PowerExchange Logger on a RAC member node with an ASM instance. This configuration provides the best performance.

The PowerExchange Express CDC log reader must be able to connect to the ASM instance as well as to the database to read the redo logs. A log reader that connects to an ASM instance must use an ASM login user ID that has SYSDBA or SYSASM authority. After the log reader reads the data, Express CDC forwards the committed changes to the PowerExchange Logger. The PowerExchange Logger logs the changes to its local log files. When PowerCenter CDC sessions run, PWXPC extracts changes from these log files.

In this sample configuration, the Express CDC log reader connects to an ASM instance and runs under a user ID and password that have SYSDBA authority. Because the Express log reader also connects to the Oracle database, Express CDC still requires a user ID and password that have the authorities described in the PowerExchange ora_orad.sql file.

The following image shows a RAC with two member nodes, where each node has a database instance and an ASM instance and one node has the PowerExchange Express CDC capture process and PowerExchange Logger:

The Express CDC capture process coordinates with the Oracle Client and ASM to retrieve change data from the redo logs.

In this scenario, a tnsnames.ora file on RAC member 1 can specify the following ASM connection descriptor that allows connection to the ASM instance on either RAC member node:

ASMTst=
  (DESCRIPTION=
    (FAILOVER=ON)
    (ADDRESS_LIST=
      (ADDRESS=(PROTOCOL=TCP)(HOST=rclnxrac21.informatica.com)(PORT = 1521))
      (ADDRESS=(PROTOCOL=TCP)(HOST=rclnxrac22.informatica.com)(PORT = 1521))
    )
    (CONNECT_DATA=
      (SERVICE_NAME=+ASM)
    )
  )

The following PowerExchange files reside on RAC member 1, where Express CDC and the PowerExchange Logger run:

CCT, CDEP, and CDCT files

PowerExchange Logger log files

PowerExchange Express CDC for Oracle configuration file

A dbmover.cfg configuration file that includes the ORAD CAPI_CONNECTION, CAPX CAPI_CONNECTION, ORACLEID, and ORACLE_CAPTURE_TYPE statements

In the PowerExchange Express CDC for Oracle Configuration file, you must specify the READER statement with the ASM parameters and the RAC statement:

RAC MEMBERS=2;
READER
   MODE=ACTIVE
   ASM_CONNECT_STRING=tns_connect_string
   ASM_EPWD=encrypted_password|ASM_PASSWORD=password
   ASM_USERID=user_id
   other optional parameters;

Specify either ASM_EPWD or ASM_PASSWORD but not both.

Express CDC for Oracle

Download Guide

Watch

Comments

Communities

Knowledge Base

Success Portal