---
title: downtime() | Tiger Data Docs
description: Get the total time dead during a heartbeat aggregate
---

Since [1.15.0](https://github.com/timescale/timescaledb-toolkit/releases/tag/1.15.0)

Sum all the ranges where the system did not have a recent enough heartbeat from a heartbeat aggregate.

There may appear to be some downtime between the start of the aggregate and the first heartbeat. If there is a heartbeat aggregate covering the previous period, you can use its last heartbeat to correct for this using [`interpolated_downtime()`](/docs/reference/toolkit/state-tracking/heartbeat_agg/interpolated_downtime/index.md).

## Samples

Given a table called `liveness` containing weekly heartbeat aggregates in column `health` with timestamp column `date`, use the following to get the total downtime of the system during the week of Jan 9, 2022.

```
SELECT downtime(health)
FROM liveness
WHERE date = '01-9-2022 UTC'
```

Returns:

```
downtime
--------
00:04:25
```

## Arguments

The syntax is:

```
downtime(
    agg HEARTBEATAGG
) RETURNS INTERVAL
```

| Name | Type         | Default | Required | Description                                         |
| ---- | ------------ | ------- | -------- | --------------------------------------------------- |
| agg  | HeartbeatAgg | -       | ✔        | A heartbeat aggregate to get the liveness data from |

## Returns

| Column   | Type     | Description                                      |
| -------- | -------- | ------------------------------------------------ |
| downtime | INTERVAL | The sum of all the dead ranges in the aggregate. |