Active Session History (ASH) Report
You can run ASH reports to analyze transient performance problems with the database that only occur during specific times.
Working with the application owner, coordinate to run ASH during a time span the issue is occuring. Start this process just prior to app\job launch.
Example Report Creation Session 1
Start: <Enter> Defaults to -15 mins Enter duration in minutes starting from begin time: Defaults to SYSDATE - begin_time Press Enter to analyze till current time So here wait for application to run then fail or experience the issue you are having. Then press <Enter> as shown below. Enter value for duration: <Enter> Sets report end to current time. Enter value for report_name: <Enter> Uses Default Report is generated... Report written to ashrpt_1_1019_1427.html
You can experiment with the capture time span or enter different values as might be more useful.
Example Report Creation Session 2
Current Instance ~~~~~~~~~~~~~~~~ DB Id DB Name Inst Num Instance ----------- ------------ -------- ------------ 1234567890 ORADB 2 oradb2 Specify the Report Type ~~~~~~~~~~~~~~~~~~~~~~~ Enter 'html' for an HTML report, or 'text' for plain text Defaults to 'html' Enter value for report_type: html Enter value for begin_time: 03/28/21 10:00:00 Defaults to SYSDATE - begin_time Press Enter to analyze till current time Enter value for duration: 03/28/21 13:00:00 Specify the Report Name ~~~~~~~~~~~~~~~~~~~~~~~ The default report file name is ashrpt_2_.html. To use this name, press <return> to continue, otherwise enter an alternative. Enter value for report_name: <ENTER> Report runs... Report written to ashrpt_4_.html
Standby (Data Guard) Detection
If running from a Standby database you will get this prompt also:
You are running ASH report on a Standby database. To generate the report over data sampled on the Primary database, enter 'P'. Defaults to 'S' - data sampled in the Standby database. If capturing for a process on your Standby database press S.