What are calculated fields in Splunk?

Calculated fields in Splunk are defined using expressions that are based on existing fields during search time. This means that they are not stored in the indexed data but are created dynamically when a search is executed. These fields allow users to perform complex calculations or transformations on the data that can enhance the analysis or reporting capabilities within Splunk.

When a calculated field is defined, it can use the values from other fields in the events and apply various functions or mathematical operations to derive new insights. This dynamic creation of fields means that calculated fields can adapt based on the context of the query being run, providing flexibility and power in data analysis.

For example, one might create a calculated field to represent the duration of an event by subtracting the start time from the end time, utilizing existing timestamp fields. This is particularly useful for analysts who want to see derived calculations without altering the underlying data or requiring modifications during indexing.