How To Increase The Maximum Size Of DCNs From 1.8KB (default) To 1.8 MB (Doc ID 2287997.1)

Last updated on NOVEMBER 04, 2021

Applies to:

Goal

The problem is noticed with the maximum size of notifications (Database Change Notifications - DCNs).

Oracle sends a list of rowids for every row that has been modified in a transaction.
But, when the number of updated rows is more than 100, Oracle does not send all rowids updated; instead it just sends an alert stating all the rows in the table have been modified (ALL_ROWS).
The reason for this is that the maximum size of notifications for DCNs is set at 1800 bytes (1.8 KB) by default.
Every rowid alert is about 180 bytes in size. So 100 rowid alerts fill the entire 1800 byte limit and the next (101st) alert causes Oracle to send a wrong notification.

Is it possible to increase the limit to 1.8MB ?
 

Solution

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.