The biggest hurdle I see is that it is a C project, unfortunately something we can do nothing about. It is so much harder to trust a random code not have to have serious implications for the database. It will take ages for someone to get comfortable with the pg-code-base way of handling errors, basic string manipulation, memory alloc/free etc.
I want to highlight the difference in "making a non-core contribution" to "understanding database internals". I am highlighting it is not the latter, but the former that is the first hurdle.
I wanted to reuse builtin pg code to parse the printed statements from logs - I ended up writing a parser (in a non-C language) myself which was faster.
Couple of points in this post, so will address a few of them:
"(Paraphrased) C is bad, and it takes forever to pick up the PG-specific C idioms"
There's probably not a productive conversation to be had about C as a language. I will say that as of C23, the language is not quite as barebones as it used to be and incorporates a lot of modern improvements.
On the topic of PG-specific C -- there are a handful of replacements for common operations that you use in PG. Things like "palloc/pfree", and the built-in macros for error and warning logging, etc.
I genuinely don't think it would take a motivated party more than a day or two to pick all of these up -- there aren't that many of them and they tend to map to things you're already used to.
"I wanted to reuse builtin pg code to parse the printed statements from logs - I ended up writing a parser (in a non-C language) myself which was faster."
It's true that the core PG code isn't written in a modular way that's friendly to integration piecemeal in other projects (outside of libpq).
For THIS PARTICULAR case, the pganalyze team has actually extracted out the parser of PG for including in your own projects:
libpg_query is a godsend of a library. I spent a lot of time writing a custom parser before I found it - was very happy to replace the whole thing. A major boon was the fingerprinting ability - one of my needs was to track query versions in metadata.
I disagree on this. Yes it's C. But I've heard people comment "I don't like writing C, but I don't mind Postgres C".
The bigger hurdle which Peter mentioned in another thread is simply building up enough expertise with the system and having the right level of domain expertise.
I want to highlight the difference in "making a non-core contribution" to "understanding database internals". I am highlighting it is not the latter, but the former that is the first hurdle.
I wanted to reuse builtin pg code to parse the printed statements from logs - I ended up writing a parser (in a non-C language) myself which was faster.