---
schema_version: "1"
id: b1c0b87ad622075d3be2bcb21920862d1ff1cece0251734783f2efa050c01c5b
title: Scheduler XML Reference
collection: mulesoft
version: current
locale: en-us
portal_url: https://docs.salesforce.com/mulesoft/current/en-us/mule-runtime/4.3/scheduler-xml-reference.md
canonical_url: https://docs.mulesoft.com/mule-runtime/4.3/scheduler-xml-reference
source_site: docs.mulesoft.com
content_type: documentation
content_hash: 6bd30ee1c870f3436d8e8b2ba7ffa19619ecc39d9818104f69cbb3a3611b8583
description: MuleSoft Documentation Site
release: "4.3"
latest: false
---
---
product: Mule Runtime
version: 4.3
---

# Scheduler XML Reference

> For the full documentation index, see: https://docs.mulesoft.com/llms.txt

A XML for the Scheduler has these elements:

- `scheduler` parent element that encloses the rest of the elements.

- `scheduling-strategy` block inside `scheduler`.

- `fixed-frequency` or `cron` element inside the `scheduling-strategy` block.

## `<scheduler>` Properties

<table><colgroup><col> <col> <col></colgroup><thead><tr><th>Attribute</th><th>Description</th><th>Example</th></tr></thead><tbody><tr><td><p><code>disallowConcurrentExecution</code></p></td><td><p>Skips the next scheduled flow execution if the last one has not ended. Next attempt to execute will be after another frequency period. Default value is <code>false</code>.</p></td><td><p><code>disallowConcurrentExecution="true"</code></p></td></tr></tbody></table>

```xml
<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns="http://www.mulesoft.org/schema/mule/core"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd">
    <flow name="componentsFlow">
      <scheduler doc:name="Scheduler" disallowConcurrentExecution="true">
        <scheduling-strategy >
          <fixed-frequency frequency="1000"/>
        </scheduling-strategy>
      </scheduler>
    </flow>
</mule>
```

## `<fixed-frequency>` Properties

<table><colgroup><col> <col> <col></colgroup><thead><tr><th>Attribute</th><th>Description</th><th>Example</th></tr></thead><tbody><tr><td><p><code>frequency</code></p></td><td><p>Triggering frequency, relative to time unit. When set to <code>0</code> or a negative value, it switches to the default (1 minute).</p></td><td><p><code>frequency="1000"</code></p></td></tr><tr><td><p><code>timeUnit</code></p></td><td><p>The time unit for the frequency and startDelay values:</p><p>MILLISECONDS, SECONDS, MINUTES, HOURS, DAYS</p></td><td><p><code>timeUnit="MILLISECONDS"</code></p></td></tr><tr><td><p><code>startDelay</code></p></td><td><p>Upon triggering the flow for the first time, Mule delays the first execution of the scheduler for a specific amount of time. This time period is expressed in the same time units as the frequency.</p></td><td><p><code>startDelay="0"</code></p></td></tr></tbody></table>

```xml
<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns="http://www.mulesoft.org/schema/mule/core"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd">

    <flow name="componentsFlow">
        <scheduler>
            <scheduling-strategy>
                <fixed-frequency startDelay="5" frequency="10" timeUnit="SECONDS"/>
            </scheduling-strategy>
        </scheduler>
        <logger message="my message"/>
    </flow>

</mule>
```

## `<cron>` Properties

For more complex scheduling strategies, you can use a cron expression.

<table><colgroup><col> <col> <col> <col></colgroup><thead><tr><th>Parameter</th><th>Default Value</th><th>Description</th><th>Example</th></tr></thead><tbody><tr><td><p><code>expression</code></p></td><td><p>-</p></td><td><p>Use a cron expression for when to do a trigger.</p></td><td><p><code>expression="1 1 1 1,7 * ?"</code></p></td></tr><tr><td><p><code>timeZone</code></p></td><td><p>Time zone passed as system property, or in machine’s operating system.</p></td><td><p>Timezone in <a href="https://docs.oracle.com/javase/7/docs/api/java/util/TimeZone.html">Java time zone</a> format</p></td><td><p><code>timeZone="America/Argentina/Buenos_Aires"</code></p></td></tr></tbody></table>

Example that uses a cron expression:

```xml
<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns="http://www.mulesoft.org/schema/mule/core"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd">

    <flow name="componentsFlow">
        <scheduler>
            <scheduling-strategy>
                <cron expression="0 0 12 * * ?"/>
            </scheduling-strategy>
        </scheduler>
        <logger message="my message"/>
    </flow>

</mule>
```

## See Also

- [Scheduler Endpoint (Trigger)](https://docs.mulesoft.com/mule-runtime/4.3/scheduler-concept)