:

GLOBAL_NAMES – Change Data Capture

Recently, I configured Asynchronous Change Data Capture  (CDC) on two Oracle 10G databases. I used the more manual approach to the  creation of the processes within the CDC options, and didn’t require a database link between the source and destination databases.

While configuring the two databases, and more specifically the initialization parameters which were required to be set, I added the following parameter to both instances:

GLOBAL_NAMES = TRUE

When GLOBAL_NAMES is set to TRUE, this forces your database links within each database to have the same global DB name (GLOBAL_NAMES) as the database that they are referencing. For our application, this was not good news. We have multiple database links within the database and used by the application which refer to various schemas in various databases, and the  database link names are embedded within the code!

It would seem that for quite a few streams and CDC administration and configuration tasks you can have a database link and it will go and get the information for you from the database that it needs to. However,  I don’t use this functionality. I’m wasn’t able to find any information on the Internet about the requirement of this parameter. What happens if I set GLOBAL_NAMES to FALSE, for example?

All I know is that I have rolled Change Data Capture out to our DEV, QA, UAT and PROD environments now and there have been no issues. It’s been in our production environment for over 1 year now and there are still no signs that we need to use this parameter so I would recommend that you turn it off if it’s causing you issues.

Change Database Global Name

It is quite common to want to change the name of your database. This will help people who are logged on using SQL Plus and have modified their glogin.sql script to show the global_name of the database instead of the SQL> text at the command prompt to easily know which database they are connected to. To change the global name it is very easy:

ALTER DATABASE RENAME GLOBAL_NAME TO TESTDB.DOMAIN.COM;

Good luck!

Like it, share it...

Category: Change Data Capture


Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *