supabase/apps/reference/docs/guides/database/extensions/pgcron.mdx

---
id: pgcron
title: 'pg_cron: Job Scheduling'
description: 'pgnet: a simple cron-based job scheduler for PostgreSQL that runs inside the database.'
---

import Tabs from '@theme/Tabs'
import TabItem from '@theme/TabItem'

The `pg_cron` extension is a simple cron-based job scheduler for PostgreSQL that runs inside the database.

## Usage

### Enable the extension

<Tabs
  defaultValue="dashboard"
  values={[
    {label: 'Dashboard', value: 'dashboard'},
    {label: 'SQL', value: 'sql'},
  ]}>

<TabItem value="dashboard">

1. Go to the [Database](https://app.supabase.com/project/_/database/tables) page in the Dashboard.
2. Click on **Extensions** in the sidebar.
3. Search for "pg_cron" and enable the extension.

</TabItem>
<TabItem value="sql">

```sql
-- Example: enable the "pg_cron" extension
create extension pg_cron with schema extensions;

-- If you're planning to use a non-superuser role to schedule jobs,
-- ensure that they are granted access to the cron schema and its underlying objects beforehand.
-- Failure to do so would result in jobs by these roles to not run at all.

grant usage on schema cron to {{DB user}};
grant all privileges on all tables in schema cron to {{DB user}};


-- Example: disable the "pg_cron" extension
drop extension if exists pg_cron;
```

</TabItem>
</Tabs>

### Syntax

The schedule uses the standard cron syntax, in which \* means "run every time period", and a specific number means "but only at this time":

```bash
 ┌───────────── min (0 - 59)
 │ ┌────────────── hour (0 - 23)
 │ │ ┌─────────────── day of month (1 - 31)
 │ │ │ ┌──────────────── month (1 - 12)
 │ │ │ │ ┌───────────────── day of week (0 - 6) (0 to 6 are Sunday to
 │ │ │ │ │                  Saturday, or use names; 7 is also Sunday)
 │ │ │ │ │
 │ │ │ │ │
 * * * * *
```

## Examples

### Delete data every week

Delete old data on Saturday at 3:30am (GMT):

```sql
select cron.schedule (
    'webhook-every-minute', -- name of the cron job
    '* * * * *', -- every minute
    $$ delete from events where event_time < now() - interval '1 week' $$
);
```

### Run a vacuum every day

Vacuum every day at 3:00am (GMT)

```sql
SELECT cron.schedule('nightly-vacuum', '0 3 * * *', 'VACUUM');
```

### Unschedule a job

Unschedules a job called `'nightly-vacuum'`

```sql
SELECT cron.unschedule('nightly-vacuum');
```

## Resources

- [pg_cron GitHub Repository](https://github.com/citusdata/pg_cron)