Re: Include extension path on pg_available_extensions

On 9/16/25 8:18 AM, Matheus Alcantara wrote:

> Any opinions on this?
>
> [1] https://www.postgresql.org/message-id/CAKFQuwbR1Fzr8yRuMW%3DN1UMA1cTpFcqZe9bW_-ZF8%3DBa2Ud2%3Dw%40mail.gmail.com
>
Just as the discussion here. Adding extension location is a good idea.
Suppose there is an amcheck 1.5 located in the $system directory. There
is also an amcheck 1.4.5 located in another path.

Strange results will then occur:
postgres=# SHOW extension_control_path;
extension_control_path
------------------------
$system
(1 row)

postgres=# CREATE EXTENSION amcheck;
CREATE EXTENSION
postgres=# select * from pg_available_extensions;

name | default_version |
installed_version | comment | location
------------+-----------------+-------------------+--------------------------------------------+----------
amcheck | 1.5 | 1.5 | functions for
verifying relation integrity | $system

This seems to be fine.

However, if another path is added, strange results will occur.

postgres=# SET extension_control_path TO
'/Users/quanzl/build/pg-availext:$system';
SET
postgres=# select * from pg_available_extensions;
name | default_version | installed_version |
comment | location
------------+-----------------+-------------------+--------------------------------------------+-------------------------------------------
amcheck | 1.4.5 | 1.5 | functions for
verifying relation integrity | /Users/quanzl/build/pg-availext/extension

The results shown here will cause confusion. It is better to show the
path used at creation.

So, it would be a better option to add a new column to the pg_extension
table.

--
Quan Zongliang