ADDM or Automatic Database Diagnostic Monitor is a tool which helps in automatic database performance monitoring.
Run the below script to run ADDM.
The following is a sample output you get if you Run the ADDM when there is no significant database activity.
DETAILED ADDM REPORT FOR TASK ‘TASK_416’ WITH ID 416
Analysis Period: from 08-AUG-2009 12:33 to 09-AUG-2009 00:30
Database ID/Instance: 1753076951/1
Database/Instance Names: SAMPLEDB/sampledb
Host Name: USER-PC
Database Version: 10.2.0.3.0
Snapshot Range: from 167 to 179
Database Time: 27 seconds
Average Database Load: 0 active sessions
THERE WAS NOT ENOUGH DATABASE TIME FOR ADDM ANALYSIS.
There was no significant database activity to run the ADDM.
The database’s maintenance windows were active during 100% of the analysis period.
The analysis of I/O performance is based on the default assumption that the average read time for one database block is 10000 micro-seconds.
An explanation of the terminology used in this report is available when you run the report with the ‘ALL’ level of detail.