Fatal NI connect error 12547, connecting to:

Sometimes you may see following error message in your alert log file. There is a similar Fatal NI error 12537 that appears in the alert log file when session exists during the session creation phase. But error 12547 comes when session terminates abnormally. For example, client application crashes without properly exiting the database, or sessions gets disconnected because of a network disconnection.

How to Enable Block Change Tracking

In RMAN incremental backup strategy, enabling block change tracking significantly increases incremental RMAN backups performance by helping RMAN to find out only changed/modified blocks (since last full backup) very fast, because only these are the blocks to be backed up during an incremental backup. List of these blocks (changed since last full backup) is maintained in the block change tracking file. In this article I will explain how to enable block change tracking.