> ## Documentation Index
> Fetch the complete documentation index at: https://doc.lucidworks.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Aggregation Properties

[localhost link]: http://localhost:3000/docs/4/fusion-ai/reference/aggregations/overview

[mintlify link]: https://doc.lucidworks.com/docs/4/fusion-ai/reference/aggregations/overview

[old doc.lw link]: https://doc.lucidworks.com/fusion/5.9/590

The aggregation process is specified by an aggregation type consisting of the following list of properties:
import { LwTemplate } from '/snippets/LwTemplate.jsx';

<LwTemplate />

| Name               | Description                                                            |
| ------------------ | ---------------------------------------------------------------------- |
| `id`               | Aggregation ID                                                         |
| `groupingFields`   | List of signal field names                                             |
| `signalTypes`      | List of signal types                                                   |
| `aggregator`       | Symbolic name of the aggregator implementation                         |
| `selectQuery`      | Query string, default `*:*`                                            |
| `sort`             | Ordering of aggregated signals                                         |
| `timeRange`        | String specifying time range, e.g., `[* TO NOW]`                       |
| `outputPipeline`   | Pipeline ID for processing aggregated events                           |
| `outputCollection` | Output collection name                                                 |
| `rollupPipeline`   | Rollup pipeline ID                                                     |
| `rollupAggregator` | Name of the aggregator implementation used for rollups                 |
| `sourceRemove`     | Boolean, default is false                                              |
| `sourceCatchup`    | Boolean, default is true                                               |
| `outputRollup`     | Boolean, default is true                                               |
| `aggregates`       | List of aggregation functions                                          |
| `params`           | Arbitrary parameters to be used by specific aggregator implementations |