Re: Schedule pg_repack job with pg_cron

Hello Sathish,

To schedule a pg_repack job using pg_cron on an Amazon RDS for PostgreSQL
instance, you need to follow a few steps. However, it’s important to note
that pg_cron is only supported on certain versions of Amazon RDS, and
pg_repack is also a separate extension that must be installed and enabled.

Here’s a general guide on how you can set this up:

*Prerequisites*

1. *Check Compatibility*: Ensure that your RDS instance supports pg_cron
and pg_repack. Both extensions need to be available and supported by the
RDS version you are using.
2. *Install pg_repack*: Ensure pg_repack is installed on your RDS
instance. You can install it via the AWS Management Console if it's
available for your PostgreSQL version. For example:
- Go to *RDS Dashboard* -> *Parameter Groups*.
- Modify the parameter group associated with your RDS instance to add
pg_repack to the shared_preload_libraries parameter.
3. *Enable pg_cron*: Similarly, ensure that pg_cron is enabled. You may
need to add pg_cron to the shared_preload_libraries in your parameter group
and reboot your instance.

*Setting Up the Job*

1. *Create the pg_cron Extension*: First, create the pg_cron extension
in your database:

sql

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CREATE EXTENSION IF NOT EXISTS pg_cron;

2. *Create the pg_repack Extension*: Similarly, create the pg_repack
extension:

sql

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CREATE EXTENSION IF NOT EXISTS pg_repack;

3. *Schedule a pg_repack Job*: You can schedule a job using pg_cron to
run pg_repack. Here is an example of how to set up a weekly job:

sql

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SELECT cron.schedule(

'weekly_repack',

'0 3 * * 0', -- This runs every Sunday at 3 AM

$$

SELECT pg_repack.repack_database();

$$);

In this example, pg_repack.repack_database() is called to reorganize the
database. Adjust the schedule expression (0 3 * * 0) as needed to fit your
desired schedule.

*Considerations*

- *Permissions*: Ensure the user running the pg_cron job has the
necessary permissions to execute pg_repack.
- *Performance Impact*: Running pg_repack can be resource-intensive.
Schedule the job during off-peak hours to minimize the impact on your
database.
- *Testing*: Before scheduling the job, test pg_repack on a
non-production instance to ensure it behaves as expected.
- *Monitoring*: Monitor the job to ensure it completes successfully and
troubleshoot any issues that arise.

By setting up pg_repack with pg_cron on Amazon RDS for PostgreSQL, you can
automate the process of reclaiming disk space and improving database
performance without significant downtime.

Thanks!

Jake

On Wed, Aug 7, 2024 at 4:53 AM Sathish Reddy <
sathishreddy(dot)postgresql(at)gmail(dot)com> wrote:

> Hi
> Please share the details for pg_repack job schedule with pg_cron from
> RDS postgres database instance level.
>
> Thanks
> Sathishreddy
>