The ADDM accepts AWR snapshots as input and provides various findings and recommentations to resolve the performance bottlenecks.
ADDM reports include :
- Top SQL Activities
- CPU bottlenecks
- Undersized memory allocations
- Excessive parsing
- I/O usage
- Concurrency issues
- Object contention
RAC and application issues
ADDM report can be generated by running addmrpt.sql script.
A portion of an ADDM report is shown below :
Finding 6: Undersized SGA
Impact is 0 active sessions, 2.96% of total activity.
The SGA was inadequately sized, causing additional I/O or hard parses.
The value of parameter “sga_target” was “700 M” during the analysis period.
Recommendation 1: Database Configuration
Estimated benefit is 0 active sessions, 2.96% of total activity.
Increase the size of the SGA by setting the parameter “sga_target” to 875 M.
Symptoms That Led to the Finding:
Hard parsing of SQL statements was consuming significant database time.
Impact is 0 active sessions, 17.82% of total activity.
Wait class “User I/O” was consuming significant database time.
Impact is 0 active sessions, 10.54% of total activity.
Article by : Anju