Re: RFC: Additional Directory for Extensions

As promised, here is a blog article that provides more context and
information about what this feature will mean in Kubernetes with
CloudNativePG:
https://www.gabrielebartolini.it/articles/2025/03/the-immutable-future-of-postgresql-extensions-in-kubernetes-with-cloudnativepg/

Thanks,
Gabriele

On Sat, 1 Mar 2025 at 10:15, Gabriele Bartolini <
gabriele(dot)bartolini(at)enterprisedb(dot)com> wrote:

> Hi everyone,
>
> I have finally been able to test the patch in a Kubernetes environment
> with CloudNativePG, thanks to Niccolò Fei and Marco Nenciarini, who created
> a pilot patch for CloudNativePG (
> https://github.com/cloudnative-pg/cloudnative-pg/pull/6546)
>
> In the meantime, Kubernetes is likely adding the ImageVolume feature
> starting from the upcoming version 1.33. I will write a blog post soon
> about how CloudNativePG will benefit from this feature. See
> https://github.com/kubernetes/enhancements/issues/4639.
>
> Although the steps are not easily reproducible by everyone, I can confirm
> that I successfully mounted a volume in the Postgres pod using a container
> image that includes only pgvector (with a size of 1.6MB - see
> https://github.com/EnterpriseDB/pgvector/blob/dev/5645/Dockerfile.cnpg)
>
> By setting:
>
> dynamic_library_path = '$libdir:/extensions/pgvector/lib'
> extension_control_path = '$system:/extensions/pgvector/share'
>
> I was able to run the following queries:
>
> postgres=# SELECT * FROM pg_available_extensions WHERE name = 'vector';
> -[ RECORD 1 ]-----+-----------------------------------------------------
> name | vector
> default_version | 0.8.0
> installed_version |
> comment | vector data type and ivfflat and hnsw access methods
>
> postgres=# SELECT * FROM pg_available_extensions WHERE name = 'vector';
> -[ RECORD 1 ]-----+-----------------------------------------------------
> name | vector
> default_version | 0.8.0
> installed_version |
> comment | vector data type and ivfflat and hnsw access methods
>
> I also successfully ran the following:
>
> postgres=# SELECT * FROM pg_extension_update_paths('vector');
>
> By emptying the content of `extension_control_path`, the vector extension
> disappeared from the list.
>
> postgres=# SHOW extension_control_path ;
> extension_control_path
> ------------------------
> $system
> (1 row)
>
> postgres=# SELECT * FROM pg_available_extensions WHERE name = 'vector';
> name | default_version | installed_version | comment
> ------+-----------------+-------------------+---------
> (0 rows)
>
> postgres=# SELECT * FROM pg_available_extension_versions WHERE name =
> 'vector';
> name | version | installed | superuser | trusted | relocatable | schema |
> requires | comment
>
> ------+---------+-----------+-----------+---------+-------------+--------+----------+---------
> (0 rows)
>
> In my opinion, the patch already helps a lot and does what I can
> reasonably expect from a first iteration of improvements in enabling
> immutable container images that ship a self-contained extension to be
> dynamically loaded and unloaded from a Postgres cluster in Kubernetes. From
> here, it is all about learning how to improve things with an exploratory
> mindset with future versions of Postgres and Kubernetes. It's a long
> journey but this is a fundamental step in the right direction.
>
> Let me know if there's more testing for me to do. The documentation looks
> clear to me.
>
> Thank you to everyone who contributed to this patch, from the initial
> discussions to the development phase. I sincerely hope this is included in
> Postgres 18.
>
> Ciao,
> Gabriele
>
> On Fri, 28 Feb 2025 at 16:36, Matheus Alcantara <matheusssilv97(at)gmail(dot)com>
> wrote:
>
>> Hi
>>
>> On Tue, Feb 25, 2025 at 5:29 PM Matheus Alcantara
>> <matheusssilv97(at)gmail(dot)com> wrote:
>> > Fixed on the attached v3.
>> >
>> After I've sent the v3 patch I noticed that the tests were failing on
>> windows.
>> The problem was on TAP test that was using ":" as a separator on
>> extension_control_path and also the path was not being escaped correctly
>> resulting in a wrong path configuration.
>>
>> Attached v4 with all these fixes.
>>
>> --
>> Matheus Alcantara
>>
>
>
> --
> Gabriele Bartolini
> VP, Chief Architect, Kubernetes
> enterprisedb.com
>

--
Gabriele Bartolini
VP, Chief Architect, Kubernetes
enterprisedb.com