---
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)