AggregationEvent

AggregationEvent is a type of derived or synthesized event used in data processing systems to summarize a set of input events within a defined window. It represents the result of applying an aggregation function, such as sum, average, count, min, or max, to a collection of raw events grouped by one or more keys.

A typical AggregationEvent carries metadata about its origin and scope. Common fields include the metric or measure name, the aggregation function, the time window (start and end), grouping keys (such as by user, device, or region), the resulting value, and the unit of measure. Some models also record the count of input events contributing to the result, along with a timestamp indicating when the aggregation was computed.

In stream processing and analytics architectures, AggregationEvents are generated by windowed computations. They can be produced by tumbling windows, which produce non-overlapping intervals, or sliding/dynamic windows, which yield overlapping results. Handling late-arriving data and out-of-order events is a typical concern, often addressed with watermarking or tolerance settings.

Common use cases include time-series dashboards, telemetry and monitoring, and business metrics. Examples include a daily total sales aggregation per region, an hourly average CPU utilization per server, or a per-minute count of user sign-ups. AggregationEvents enable compact summaries that support efficient querying, alerting, and visualization.

See also: raw events, derived events, windowing, stream processing, and time-series analytics.