The "aggregation interval" is the time in minutes that the AppDynamics for Databases writes out collected performance data to disk, and therefore allow it to be visualized in the user interface. By default, AppDynamics for Databases logs data every minute. Depending on your environment this may be too frequent, and you may be happy with longer intervals.

There are positives and negatives to short aggregation periods, check the list below to help you work out what is best for you.

Positives:

• More granularity - See within a very small time window what is happening

• Almost real-time access to data - If you need to know what's going on in your databases in almost real time, then shorter aggregation intervals are best

Negatives:

• More storage is required to store the history - If you want to keep weeks or even months of granular data, then having short aggregation intervals will consume much more disk space. e.g. Data in chunks of one minute, will consume almost 5 times that of 5 minute aggregation intervals

• (Slightly) more overhead - AppDynamics for Databases will run additional monitoring queries at the end of each interval, therefore shorter aggregation intervals will mean that more queries are hitting your monitored database and therefore the overhead will be more. This will probably not be a big issue, as the overhead to monitoring should be negligible.

How granular do you need your data?

Check out the screenshot below to compare different intervals.

10 Seconds – 1 Minute – 5 Minutes – 15 Minutes

Set the Aggregation Interval

You can set the aggregation interval either through the UI or if you need more granularity, such as a 10 second interval, you can set the aggregation interval in the dbtuna properties file. Such fine granularity is supported only on the Oracle platform. The aggregation interval is set to 1 minute by default.

Set the Aggregation Interval via the UI

Using the collector Setup window, you can set the aggregation window to 1, 2, 5, 10 or 15 minutes.

1. On the Main Menu, click Setup and then on the Setup window,
   to add a new collector and configure its aggregation interval, click Add Collector,
   to modify the aggregation interval of an existing collector, click the name of the collector.
2.  On the Setup window, from the Aggregation Interval list choose the desired interval. 
3. Click Save Changes.

Set the Aggregation Interval via the dbtuna Properties File

AppDynamics for Databases supports sub-minute aggregation intervals for the Oracle platform. For example, some customers use 10 second aggregation intervals. To set this use the agg-interval property in the <AppD4DB install directory>/agent/dbtuna.properties file. This is the aggregation interval represented in minutes, however it can be a decimal number.

For example for

• 30 second aggregation intervals set agg-interval to .5
• 10 second aggregation intervals, set agg-interval to 0.1667

Note: A sub minute aggregation interval incurs additional overhead both on the AppDynamics for Databases server and the Oracle database. Test to ensure that your systems can handle the additional overhead and upgrade capacity as required.

This is the section of the dbtuna.properties file that controls the sampling and aggregation intervals.

# Collector Settings
agg-interval=.1667
sample-rate=999
samples-per-second=1
cpu-miliseconds=602