# `RollupHistogramGrouping` [interface-RollupHistogramGrouping]

| Name | Type | Description |
| - | - | - |
| `fields` | [Fields](./Fields.md) | The set of fields that you wish to build histograms for. All fields specified must be some kind of numeric. Order does not matter. |
| `interval` | [long](./long.md) | The interval of histogram buckets to be generated when rolling up. For example, a value of `5` creates buckets that are five units wide ( `0-5`, `5-10`, etc). Note that only one interval can be specified in the histogram group, meaning that all fields being grouped via the histogram must share the same interval. |