WebSphere Business Space powered by WebSphere, Version 6.2.0


Aggregation functions

Aggregation functions are used to operate on a set of values to return a single value; for example, to provide the value of a key performance indicator (KPI) or measure based on a set of metrics.

The following table describes each aggregation function.
Aggregation Function Description
Minimum Returns the smallest value from the set of values
Maximum Returns the largest value from the set of values
Sum Adds the values and returns the total
Count Counts the number of values
Average Calculates the average of the set of values.

When a counter or integer metric is aggregated as a measure using the Average function, the resulting value is an integer. To get decimal precision, you must aggregate using an underlying metric that is of type Decimal. Counters and integer metrics can be copied to a decimal metric if decimal precision is required.

Standard Deviation Calculates how widely spread the values are

Null values are not included in the calculation. For example, the Count function counts the number of values that are not null. Suppose you create a metric that can have a value of either 0 or 100. You define a measure based on the metric and use the Count aggregation function. If there are three instances of the measure, one with a value of 0, a second with a value of 100, and a third with no value (null), the count is 2.

Similarly, the Average function averages the values that are not null. Suppose you have an Average Order Amount measure that points to an Order Amount metric. At run time, you have three instances with order amounts of $100, $200, and null. The Average Order Amount measure ignores the null instance and has a value of $150.

Available aggregation functions

Only certain types of functions are valid based on the source you choose. The following table shows the valid functions based on the type of metric. Stopwatches and counters are included at the end of the table.
Type Valid Aggregation Functions
Boolean Count
Date Minimum, Maximum, Count
DateTime Minimum, Maximum, Count
Decimal Average, Minimum, Maximum, Sum, Count, Standard deviation
Duration Average, Minimum, Maximum, Sum, Count
Integer Average, Minimum, Maximum, Sum, Count, Standard deviation
String Count
Time Minimum, Maximum, Count
Stopwatch Average, Minimum, Maximum, Sum, Count
Counter Average, Minimum, Maximum, Sum, Count, Standard deviation



Support | Terms of use | Contact IBM
Copyright IBM Corporation 2007, 2008. All Rights Reserved.
This information center is powered by Eclipse technology. (http://www.eclipse.org)