Extensions could be neat, there doesn't seem to be a high-level Rust API for it (in the style of ruru or rust-cpython) yet though, only incomplete-looking bindgen: https://github.com/posix4e/rpgffi
[0] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=postgresql
Nowadays most developers comes from memory-managed languages => for us, C is a scary land where it's really hard to get things right when you don't have all the prerequisite knowledge (what's the stack ?) => the language is really old, you don't have all the fancy and useful tools and syntactic sugar (package manager, proper error handling, generics) => then we don't want to invest a lot of time to learn a difficult language that is so unproductive. => and even if we do out of curiosity, we'll most likely never feel confident enough to dig into an open-source project and contribute.
Rust on the other hand, is like C but with a personal IA assistant (the compiler) and all the syntactic sugar you're used to (and even more if you're not familiar with the ML family). That's what's attracting so many web developers to Rust !
In my opinion it means that, in a somewhat near future, the amount of potential contributors for projects written in Rust could be higher than for projects written in C. And those contributor are also likely to be more productive, thanks to the language features and tooling.
What's annoying about OP's email is that they clearly did no research on the matter. You can find many discussions on the list about "upgrading" to C++, and there has been much wringing of hands. The last I heard, it sounded like a faction was considering having the project build with a C++ compiler rather than a C compiler for better type checks and as a step on that path.
Wait, which runtime checks are you talking about ? This is a recurring FUD we often see on HN about Rust and I'd like to clarify this point.
IIRC, there is no mandatory runtime check in idiomatic Rust except UTF8 validation for strings[0]. There is no overflow checks on numbers, and no bounds checking when using iterators[1]. Another known overhead is the default use of siphash in hashmaps for DoS prevention[2], but this is not really a «runtime check».
Do you have anything else in mind ?
> Speaking of which, the PostgreSQL project is healthy and has many, many contributors.
Indeed, and as I said, I'm not advocating for a port of PostgreSQL in Rust. But for other projects that suffer from a lack of attention[3], it could be a good move.
> And while we're discussing developer productivity, I can't even imagine the build time of a Rust port.
touché, but compile time is one of the biggest focus of the Rust core team atm, so I'm confident things will improve in 2017 :)
[0]: which can be worked around if need be by using &[u8] instead of &str (see: https://news.ycombinator.com/item?id=13268051 from /u/burntsushi)
[1]: there are bounds checking when you access array elements through indexes, but most of the time you don't do that since iterators are great. If you really need to, and this have a performance impact, you can opt-out the bound checking in unsafe block.
[2]: But this is opt-out by using a different hash function, if you use your hashmap in a non adversarial environment.
[3]: like librsvg which was chronically under-maintained.
Regarding [2], I think it's safe to consider any software that takes input as operating in a hostile environment.
Just array indexing? It would be interesting to see your criticism fleshed out.
I am not sure your criticism will amount to anything if array access is it, though. Posrgres is full of custom data structures and macros as it is. StringInfo and stuff like that -- they are not just "using the language", writing nice simple C code. Probably because databases really push you to use advanced techniques in places.
I wish we didn't need bounds checking; the problem could be solved with dependently typed languages. Unfortunately Rust just panics when you access out of bounds, and doesn't warn you at compile time. Rust isn't really all that impressive.
I know nothing about Rust, but you might find Oleg Kiselyov's: "Eliminating Array Bound Checking through Non-Dependent Types" interesting.
http://okmij.org/ftp/Haskell/eliminating-array-bound-check.l...
You may also like:
http://okmij.org/ftp/Haskell/number-parameterized-types.pdf
http://okmij.org/ftp/Computation/resource-aware-prog/tfp.pdf
I don't think Rust can ever replicate the Haskell implementation identically (if we had HRTB over types), as type parametrism is gone (see: specialization RFC). However, lifetime parametrism serves a similar role in Rust, and lifetimes are closer to a concept of "instance" than types.
This is an old strawman. No one is asking the users to write Rust and a change in developer tooling doesn't by itself change things for users. The question is whether tools help developers help users.
The logical decoder: http://pgxn.org/dist/jsoncdc
The bindings: https://github.com/posix4e/rpgffi
The extensibility of Postgres is really profound -- there are so many things you can do, and so much internal functionality you can access, without having to recompile the database. The way extensions are loaded also mitigates the risk of what can be admittedly tricky issues relating to safety. Extensions run in backend processes, not the postmaster.
If rewriting Postgres happens, I hope it would be gradual. You can replace a lot of the core with extensions, and the scope for extension is ever increasing. So say you wrote a storage engine in Rust. Writing a foreign data wrapper for it would give you a way to use it from Postgres for all your tables; but you wouldn't have to write a SQL parser, client manager, permissions system, or any of the rest of that stuff.
Although the C stuff is a little gritty, a lot of what goes on in a database is gritty "because it is" and that low-level control is needed to deliver on tail latency, fault tolerance or simple storage efficiency. For example, Postgres has code to recover from malloc failing.