---
title: Composite Monitor Use Cases
description: >-
  Common use cases for composite monitors including error rates, frequent
  metrics monitoring, step monitoring, and notification delays.
breadcrumbs: Docs > Monitors > Monitor Guides > Composite Monitor Use Cases
---

# Composite Monitor Use Cases

## Overview{% #overview %}

This guide lists non-exhaustive use cases for composite monitors. These examples illustrate how composite monitors can be configured to address various use cases in monitoring environments:

- Error rates
- Monitor frequent metrics
- Step monitor
- Renotifying on recovery
- Delay on notification

## Error rates{% #error-rates %}

Alert when the error rate exceeds a threshold only when hits are above a certain number.

Create two monitors:

- **Monitor A**: Alert when `trace.requests.request.errors / trace.requests.request.hits > X`
- **Monitor B**: Alert when `trace.requests.request.hits > Y`

**Composite Monitor C**: Alert when both Monitor A and Monitor B are in alert (A && B).

| Monitor A                            | Monitor B                      | Composite Monitor C                   |
| ------------------------------------ | ------------------------------ | ------------------------------------- |
| **Alert** Error rate above threshold | **Alert** Hits above threshold | **Alert**                             |
| **Alert** Error rate above threshold | **OK** Hits below threshold    | **OK** Only 1 condition met, no alert |
| **OK** Error rate below threshold    | **Alert** Hits above threshold | **OK** Only 1 condition met, no alert |

For more state combinations, see [Composite Monitor](https://docs.datadoghq.com/monitors/create/types/composite.md#computing-trigger-conditions).

## Monitor frequent metrics{% #monitor-frequent-metrics %}

Monitor latency for services, ignoring occasional spikes due to low traffic. For example, a period of time during the night where services report very few values.

Create two monitors:

- **Monitor A**: Alert when `latency > X`
- **Monitor B**: Alert when `sum:latency{*}.rollup(count) > Y` over the last 1 hour

**Composite Monitor C**: Alert when both conditions are met.

| Monitor A                         | Monitor B                     | Composite Monitor C            |
| --------------------------------- | ----------------------------- | ------------------------------ |
| **Alert** Latency above threshold | **Alert** More than Y metrics | **Alert**                      |
| **Alert** Latency above threshold | **OK** Less than Y metrics    | **OK** Not enough metrics      |
| **OK** Latency below threshold    | **Alert** More than Y metrics | **OK** Latency below threshold |

## Step monitor{% #step-monitor %}

Trigger an alert in the absence of a paired metric. For example, log metrics for sent/received, down/up, or create/resolve. You can adjust the evaluation windows for the monitors if paired metrics are expected to be N minutes apart.

- **Monitor A**: Alert when `action:create` is above 0
- **Monitor B**: Alert when `action:resolve` is above 0

**Composite**: Alert if `a && !b`.

| Monitor A                       | Monitor B                        | Composite Monitor C                  |
| ------------------------------- | -------------------------------- | ------------------------------------ |
| **Alert** Action create above 0 | **Alert** Action resolve above 0 | **OK**                               |
| **Alert** Action create above 0 | **OK**                           | **Alert** Action resolve not present |
| **OK**                          | **Alert** Action resolve above 0 | **OK**                               |

## Renotifying on recovery{% #renotifying-on-recovery %}

Renotify on recovery using two monitors with a `timeshift`.

- **Monitor A**: Current metric status
- **Monitor B**: Past metric status using `timeshift`

**Composite Monitor**: Logic is `!a && b`.

| Monitor A                   | Monitor B                   | Composite Monitor C |
| --------------------------- | --------------------------- | ------------------- |
| **Alert** Real-time metric  | **Alert** Past metric       | **OK**              |
| **Alert** Real-time metric  | **OK** Metric not triggered | **OK**              |
| **OK** Metric not triggered | **Alert** Past metric       | **Alert**           |

## Delay on notification{% #delay-on-notification %}

Alert after errors persist for a set duration. For example, a set of errors triggered for at least 15 minutes.

- **Monitor A**: Real-time metric
- **Monitor B (timeshifted)**: Metric shifted by X minutes

**Composite Monitor**: Alert if `a && b`.

| Monitor A                   | Monitor B (timeshifted)     | Composite Monitor C |
| --------------------------- | --------------------------- | ------------------- |
| **Alert** Real-time metric  | **Alert** Past metric       | **Alert**           |
| **Alert** Real-time metric  | **OK** Metric not triggered | **OK**              |
| **OK** Metric not triggered | **Alert** Past metric       | **OK**              |

## Further reading{% #further-reading %}

- [Composite monitor type](https://docs.datadoghq.com/monitors/types/composite.md)