# Activity Tracking

Starting with release 0.12, IRONdb supports tracking of metric activity without the expense of reading all known time series data to find active ranges. The activity of a metric is tracked at a 5 minute granularity. Any ingestion of a metric will mark that 5 minute period that the timestamp falls into as active for that metric. Activity periods are stored in the [surrogate database](/platform-docs/irondb/getting-started/configuration.md#surrogate_database).

This activity tracking also coalesces nearby active ranges. Any activity on a metric within an 8 hour window marks that metric as active for that 8 hour span. For example, if you have a metric that arrived with the timestamp: `2018-07-03T11:00:01:123Z` and then nothing else arrived until `2018-07-03T19:00:02:123Z`, the metric would be considered *inactive* in the 8 hour span between these 2 timestamps. If, later, some late data arrives and we see a timestamp at: `2018-07-03T14:00:01:123Z`, then the entire 8 hour span is considered *active* for purposes of querying.

See [Searching Tags](/platform-docs/irondb/metric-names-and-tags.md#tag-queries) on how to query activity periods for a given list of metrics.

This activity tracking only applies to data ingested after the upgrade to `0.12` or later. Any data ingested prior to installation of `0.12` will be invisible to the activity tracking code. However, IRONdb also ships with an API to rebuild activity tracking data by reading the actual datapoints for a metric to determine its activity ranges. Since this is an expensive operation it has to be triggered for a list of metrics by an operator.

## Rebuilding Activity Data

> Do not trigger this API until you have upgraded all IRONdb nodes to `0.12` or later.

### URI

* `/surrogate/activity_rebuild`

### Method

POST

### Inputs

A JSON document which lists the set of metrics to rebuild activity data for, with the syntax:

```
[
   {
      "check_uuid":"1fd7c873-0055-4bd3-a16a-2137b111e71a",
      "metric_name":"foo"
   },
   {
      "check_uuid":"1fd7c873-0055-4bd3-a16a-2137b111e71a",
      "metric_name":"bar"
   },
   {
      "check_uuid":"1fd7c873-0055-4bd3-a16a-2137b111e71a",
      "metric_name":"baz|ST[a:b,c:d]"
   }
]
```

> The above will rebuild activity for the 3 metrics listed in the document.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.apica.io/platform-docs/irondb/administration/activity-tracking.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.