ADDM、AWR

The AWR Compared Periods report shows the difference between two periods (or two AWR reports,which equates to four snapshots).

Automatic Database Diagnostic Monitor(ADDM) ADDM 在创建每个AWR快照之后会自动运行.每次创建快照之后，ADDM都会分析与最后两个快照对应的时段.多数情况下,ADDM会为检测到的为题提供建议解决方案,甚至可以量化这些建议方案的优势.ADDM分析的结果存放在AWR中.

How to create and drop baseline?
Create baseline:
BEGIN
DBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE (start_snap_id => 270,
end_snap_id => 280, baseline_name => 'peak baseline',
dbid => 3310949047, expiration => 30);
END;
/

Drop baseline:
BEGIN
DBMS_WORKLOAD_REPOSITORY.DROP_BASELINE (baseline_name => 'peak baseline',

cascade => FALSE, dbid => 3310949047);
END;
/
After you create baseline,you can see the information by querying the view “dba_hist_baseline”.