11g Grid | Creating and Comparing a Baseline

As a DBA,  one can’t look at entire application performance. But there is an easy way to see if database server load is normal when you hit issues . It’s done by creating and comparing baselines/snapshots under 11g Grid.  This option doesn’t work with 10g so you will need 11g database.

This post will cover-

• Creating a single Baseline
• Creating a Repeating Baseline
• Comparing a Baseline to Another Baseline or Pair of Snapshots

Baseline Interval Type

The first thing you need to do is locate a normal day and create reference point.

To create a single baseline
From the Database Home page, click Server.The Server page appears.

1. Under Statistics Management, click AWR Baselines.The AWR Baselines page appears with a list of existing baselines displayed.
2. Click Create.The Create Baseline: Baseline Interval Type page appears.
3. Select Single.
4. Click Continue.The Create Baseline: Single Baseline page appears.
5. In the Baseline Name field, enter a name for the baseline.
6. Under Baseline Interval, select whether to use a snapshot range or a time range for the baseline. Do one of the following:
   • To use a range, select Snapshot Range. Complete the following steps:
     • Under Select Time Period, select a start time for the baseline by selecting Period Start Time and the snapshot icon below the Active Sessions chart that corresponds to the desired start time.
     • Select an end time for the baseline by selecting Period End Time and the snapshot icon below the Active Sessions chart that corresponds to the desired end time.
     • Optionally, to view older snapshots that are not displayed below the Active Sessions chart, expand Change Chart Time Period. Enter the desired start date in the Chart Start Date field and the desired end date in the Chart End Date field, and click Go.

     

   • To use a time range, select Time Range. Complete the following steps:
     • In the Start Time fields, select a start time for the baseline.
     • In the End Time fields, select an end time for the baseline.
7. Click Finish.

Creating a Repeating Baseline

A repeating baseline is a baseline that repeats during a time interval over a specific period. For example, a repeating baseline may repeat every Monday from 8:00 a.m. to 10:00 a.m. from February 6, 2009 to February 6, 2010.

To create a repeating baseline:

1. From the Database Home page, click Server.The Server page appears.
2. Under Statistics Management, click AWR Baselines.The AWR Baselines page appears with a list of existing baselines displayed.
3. Click Create.The Create Baseline: Baseline Interval Type page appears.
4. Select Repeating and then click Continue.The Create Baseline: Repeating Baseline Template page appears.
5. In the Baseline Name Prefix field, enter a name prefix for the baseline.
6. Under Baseline Time Period, specify the time of the day that you want the baseline to begin collecting AWR data and the duration of the baseline collection.
7. Under Frequency, do one of the following:
   • Select Daily if you want the baseline to repeat on a daily basis.
   • Select Weekly if you want the baseline to repeat on a weekly basis, and then select the day of the week on which the baseline will repeat.
8. Under Interval of Baseline Creation, complete the following steps:
   1. In the Start Time fields, select a date and time in the future when the data collection should begin.
   2. In the End Time fields, select a date and time in the future when the data collection should end.
9. Under Purge Policy, enter the number of days to retain captured baselines.
10. Click Finish.A baseline template with the same name as the baseline name prefix will be created.
11. A baseline template is a specification that enables Oracle Database to automatically generate a baseline for a future time period.

Comparing a Baseline to Another Baseline or Pair of Snapshots

When performance degradation occurs over time, you can run the AWR Compare Periods report to compare the degraded performance.

To compare a baseline to another baseline

1. From Database Home page, click Server.
2. Under Statistics Management, click Automatic Workload Repository.
3. Under Manage Snapshots and Baselines, click the link next to Baselines.
4. Complete the following steps:
   1. Select the baseline to use for the report.At least one existing baseline must be available.
   2. From the Actions list, select Compare Periods and click Go.

   The Compare Periods: Second Period Start page appears. Under First Period, the selected baseline is displayed.

5. Compare the baseline selected in the first period to another baseline or a pair of snapshots. Do one of the following:
   • To compare to another baseline, select Select a Baseline and the baseline you want to use in the second period, and then click Next.The Compare Periods: Review page appears. Go to Step 7
   • To compare to a pair of snapshots, select Select Beginning Snapshot and the beginning snapshot to use in the second period, and then click Next.The Compare Periods: Second Period End appears. Proceed to the next step.
6. Select the ending snapshot for the snapshot period that will be included in the report and then click Next.
7. Review the periods to be included in the report and then click Finish.
8. Click Report to view the report.
9. One of first thing I look for is “Service Statistics”

To save the report as an HTML file, click Save to File.