Frequently Asked Questions

Releasing on PGXN

WTF is an “extension”?
An extension is a piece of software that adds functionality to PostgreSQL itself. Examples are data types (citext, hstore), utilities (dblink, pgTAP), and procedural languages (PL/Perl, PL/R), among others. See Extending SQL for details.
What’s allowed to be released on PGXN?
Open-source PostgreSQL extension release packages. The How To documents the contents of such packages. Following the CPAN example, “no commercial software of any kind, not even share/guilt/donateware, will be allowed…any other policy would be open to nitpicking, or maybe even legal challenges.”
What’s not allowed to be released on PGXN?
Non-package files (that is, files that are not tarballs, bzip-balls, or zip archives), closed-source distributions, and distributions with no license.
Who can release on PGXN?
Any registered user.
Who can register for PGXN?
Anyone who applies. Such registrations will be approved by volunteers, but we’re usually pretty quick to respond to requests.
So how do I apply?
Head on over to PGXN Manager and hit the “Request Account” link. Once you’ve signed up, unless you’re obviously a troll, your account will be quickly approved.
Okay, I have an account and want to release an extension. Is there a release
approval process?
Short answer: No, because PGXN needs to KISS. Longer answer: No. Again following the CPAN example, PGXN “is and will stay an open and free forum, where the authors decide what they upload. Any further selection belongs to different fora.” This is because “the first goal of PGXN is to make it easy to submit code and redistribute it. Ease of use and quality control are not the central problems [it] tries to solve.” (Original quotation lost to time and internet entropy.) Frankly, moderation of releases is a significant reason that other communities have failed to duplicate the success of CPAN.
Great, so how do I create an extension distribution and release it?
Basically, you upload an archive file with a META.json file describing the distribution. Have a look at the How To for all the details.
I read that, but it seems like an awful lot of work for something that should be
automated. Is there any way I can automatically have my extension appear on PGXN
when I make a release on GitHub?
Yes! You can use the pgxn-tools Docker image as part of your release workflows. It supports both testing an extension with multiple versions of Postgres, as well as releasing extensions on GitHub and PGXN. For details, check out these blog posts:
Is there some place I can go to ask questions and get help from like-minded PGXN
Yes, there is a Google Group for this very purpose. Join us!
How does PGXN make it easy to distinguish the garbage from the viable
The first step is the PGXN search engine, accessible via the home page, which will allow you to find extensions relevant to you and to read their documentation. This will “often [be] enough to distinguish the good stuff from the crap,” as Robert Haas says. As more extensions are released on PGXN with competing features and functionality, the addition of ratings features and dedicated testing will also make it easier to evaluate competing options.

PGXN Client

Is there a command-line client for installing extensions from PGXN?
There is! Install it with this command:
sudo easy_install pgxnclient
Then you can install PGXN extensions with a simple command:
pgxn install pair
Run pgxn help to get a list of supported commands; or check out the introductory blog, the complete documentation or the source code.
How does the command-line client work?
It uses JSON-based API available on every PGXN mirror to find, download, build, and install extensions. It relies on PGXS to do the heavy lifting to build extensions.
What about Windows?
The PGXN client follows the lead of the PostgreSQL core on installing extensions. If support for installing extensions on Windows improves such that a compiler is no longer required, the PGXN client will be modified as appropriate to take advantage of it. This applies not specifically to Windows, but to the ability of the core installer (or any future community-supported installer) to work on any platform.
What kind of security does PGXN have?
Each release package has an accompanying SHA1 hash that the PGXN client verifies before installing an extension.

Contributing to PGXN

Under what license is PGXN’s source code distributed?
The PostgreSQL License. Note that the actual extensions themselves may be under any open source license, determined by their authors.
Can other people contribute to PGXN?
Definitely! Contributions and help with refining the specification are very welcome. Major code contributions may be funded out of the PGXN fund based on circumstances. Any contributions must be submitted under The PostgreSQL License.
What about mirroring? Can I create a PGXN mirror?
Absolutely! See mirroring for the details.
Who owns and runs PGXN?
Currently, PGXN is hosted on a box owned by depesz. Eventually it may run on community servers, as the Web Team determines. Or it may end up on one or more servers to be contributed to the PostgreSQL Funds Group. In any case, the PGXN master index and server will always be contributed to the PostgreSQL community.
Where is the PGXN source code hosted?
On GitHub. Please feel free to fork and send pull requests!
What language is PGXN written in?
Mostly Perl. The database used by PGXN Manager is written in SQL, PL/pgSQL, and PL/Perl — and even uses semver, a semantic version data type written in C and distributed right here on PGXN!
Is there an API?
Yes! The PGXN API provides centralized index and API of distribution metadata, as well as the search APIs used here.
Is the PGXN logo available for use?
Yes, see identity for the license details and downloadable artwork.