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Honest question: When would it ever really make sense to use Rust on the server for a service that interacts with a SQL database heavily enough to justify using

Honest question: When would it ever really make sense to use Rust on the server for a service that interacts with a SQL database heavily enough to justify using such a library? Wouldn't waiting on the network eat up any possible performance gain you could expect from Rust vs something like the JVM or Go runtime? Before modern day JavaScript JITs, relational database systems were the epitome of dynamic runtime systems. There's so much performance variability in the query planner, network, disk caching, etc, to make garbage collection a rounding error. Zero-cost abstractions are just not a particularly useful thing in this context from what I can tell. Even if you do have genuinely CPU-bound tasks, why wouldn't you use Rust for those modules + call it via FFI from whatever is doing most of the boring business logic? If it's just about static-type-check-all-the-things! I just can't get excited about it vs something like Go.

joseph 11y ago
On the other hand, if you're already using Rust, why switch to another language just to talk to the database?
- Animats 11y ago
  There are much simpler standard ways to talk to a database from Rust: https://crates.io/crates/postgres/ https://crates.io/crates/postgres/ https://crates.io/crates/mysql/ https://crates.io/crates/mysql/ This is an experimental approach. It might or might not be useful, but you don't have to use it.
  - brandonbloom 11y ago
    +1 It seems like the intersection of good use case for Rust and need to use SQL, will also intersect with "minimal SQL needs", hence preference for simpler libraries.
    - deleted 11y ago
      [deleted]
      - brandonbloom 11y ago
        Mentioned below where? If you're talking about query string construction performance, I'm not sure I've ever seen even a Ruby application where query string building was a bottleneck vs the network.
        steveklabnik 11y ago
        Sorry, as you replied I had deleted my comment, because I decided I'd rather not get into an argument about this :) I will give you the link though: https://news.ycombinator.com/item?id=11045700 https://news.ycombinator.com/item?id=11045700 <- "Diesel performs 33% faster than rust-postgres, and will be competitive with if not faster than ideomatic C. "
        brandonbloom 11y ago
        Forgive me, I didn't intend to be so argumentative. I genuinely want to understand. I'm trying to figure out if there are whole categories of use cases that I just don't have any exposure to. As a side note: I keep trying Rust over and over again, and just can't get in to it. I think my brain just doesn't work that way. For my hobby project that needs super low level perf, I've moved a codebase from C, to Rust, and now to http://terralang.org/ http://terralang.org/ and I'm finally quite satisfied with how the project is going.
        rabidferret 11y ago
        It's a bit late here, but feel free to DM me in our Gitter room and I can give you a full explanation tomorrow.
        steveklabnik 11y ago
        Naw, it was my response that was more so than I wanted it to be. No worries. :) Rust focuses on "zero-cost abstractions", that is, if you had to implement a feature yourself, you couldn't do it any better. So this library, while more complex than a straightforward binding, has more features that are useful, like increased safety, while also being faster. A win-win. And very much in line with Rust's overall philosophy.
  - joseph 11y ago
    That's valid, but ORMs have been pretty standard for years now too. Most mature languages have either ORMs or some database abstraction libraries, so it's good to see Rust getting those now.
    - mercurial 11y ago
      > Most mature languages have either ORMs or some database abstraction libraries And a lot of them really suck, too, because it's a hard problem. I'll take query builders or raw SQL over ORMs any day of the week.
rabidferret 11y ago
Short version: Because Rust's type system is a joy to use, and the reason I made Diesel was to try and push it forward in higher level contexts. I'm finding myself more productive in Rust than I am in any other language. Long version: http://bikeshed.fm/49 http://bikeshed.fm/49
hueving 11y ago
Workers that consume tasks and write state to a db system can easily have lots of work that rust's performance guarantees would help with.
- brandonbloom 11y ago
  Hopefully such systems won't be doing a fair amount of dynamic query generation... vs simple pre-baked CRUD operations.
threatofrain 11y ago
In my limited experience using both Go and Rust for hobbyist web scraping, I haven't found either language to have a significant edge in development difficulty. Go's most salient edge over Rust would be in the more numerous and mature libraries. So if Rust is not substantially easier or harder than Go, when Rust catches up to Go in the library ecosystem, I can see why people might want to use Rust. Also, it's nice to have better language support for functional strategies.
- brandonbloom 11y ago
  I think that Rust is substantially harder than Go. At least extrapolating from my personal experience and the 6+ highly-skilled people I've watched learn both Go and Scala simultaneously.
  - kibwen 11y ago
    I wouldn't generally compare Rust against Scala, as Rust's type system is less ambitious and the language itself has far fewer concepts.
  - danieldk 11y ago
    I just started learning Rust and its type system is much simpler than Scala. What makes it powerful is some well-designed somewhat orthogonal features (generics, type traits, the ownership system, algebraic data types, macros). I didn't pick up Rust as quickly as Go. However, that's not really surprising, because Go is approximately the lowest common dominator of modern statically typed languages minus generics. (In a good and bad way.) At any rate, I started learning Rust ~2 weeks ago and I am already writing small libraries, programs, etc. for my daily work. Although that took a bit more time than Go, it's also a much more pleasing language to write in (the lack or sum types or generics in Go is very annoying) and you get more safety guarantees.
    - Manishearth 11y ago
      > it's also a much more pleasing language to write in (the lack or sum types or generics in Go is very annoying) Interesting anecdote: Last year, for a course I had to write the assignments in Go. As a Rustacean, I grumbled about the lack of sum types a lot, and made various hacks via interfaces writing unidiomatic Go code to simulate them. My code design was also very Rust-y and unidiomatic. This year, I'm TAing the same course, and there's a similar assignment. One student's submission was eerily similar to my design (by now I knew that it was unidiomatic), down to the hacks used. It also contained a comment saying "missing Rust's enums" (my code contained a similar comment to explain the hacks). At first I thought it may have been copied from my code (which can be found if you're looking for it), but it was different enough in other areas. I dug a bit and found that the student was indeed a rustacean. It's rather interesting that two rustaceans used the exact same hacks and same overall design when asked to code in Go. Surprisingly, I don't miss generics too much in Go. interfaces used to make me cringe due to the extra runtime cost (since I knew Rust before learning Go, and such solutions would make me cringe in Rust), but once I got used to Go I learned to use them properly. Named interfaces are pretty easy to use and let you structure the code decently well, just like proper generics. They may have a runtime cost, but Go doesn't put as much focus on that as Rust. On the other hand, easy-to-use non-hacky sum types are something I miss from Go all the time.
mintplant 11y ago
What about Go gets you excited where Rust doesn't?
- brandonbloom 11y ago
  In the context of my original post: 1) garbage collection, which isn't a big deal for most server applications and 2) simplicity, where the complexity of Rust only buys me marginal performance of questionable utility for the sorts of use cases where I'd be talking to a SQL database.
  - rabidferret 11y ago
    Diesel's selling point isn't actually the performance aspect. It's the safety and productivity.
    - brandonbloom 11y ago
      We're not going to settle the dynamic vs static debate in this thread, so I'll refrain from commenting on safety and productivity :-) Anyway, I don't mean to dump on your work. It seems like it's actually quite a nice implementation. I'm just questioning 1) the size of the audience and 2) Whether or not the audience who thinks they want this should actually want this.
      - pcwalton 11y ago
        If the size of your audience is your overriding concern, you shouldn't be writing your ORM in Go or Rust.
  - pcwalton 11y ago
    But the sorts of use cases where you'd be talking to a SQL database do benefit from generics and ADTs. For example, generics are good to avoid having to write for loops over and over, which is pretty pointless for application code (and, I'd argue, for systems code as well--for loops are just bad). Pattern matching is nice for high-level app logic, which often has the flavor of "if A, do X; if B, do Y; else do Z". Generics enable try!, which is a lot nicer than C-style error handling. And so on.
ossreality 11y ago
I like writing Rust for more reasons that CPU efficiency. In fact, that's behind: strong memory safety, Option/no-null (probably lumps in with "strong memory safety") and of course generics and the type system at large. The speed is honestly a nice benefit. (I'm not being sassy, I don't have speed intensive applications and still reach for Rust).
sedatk 11y ago
memory is a critical resource for scalability and gc's are not good at it.
jeffdavis 11y ago
I think it's hard to tell whether a language (by itself, not counting the libraries) will be good for something until you try. Rust has enough going on that some creative people might find some really useful things it can do in surprising spaces. Think about JavaScript and Node.js. Who would have predicted that?
pcwalton 11y ago
Even if we were to assume that GC is better than manual memory management for servers (something I think is not really true), this presupposes that the non-memory-management-related parts of Go's type system are better than those of Rust. I disagree with that for many reasons.
Keats 11y ago
For me Rust compiler and type system is much much better than the one in Go. Rust is still very far from Go right now though but I like the "if it compile, it works" which is not a certainty in Go.

joseph 11y ago

On the other hand, if you're already using Rust, why switch to another language just to talk to the database?

Animats 11y ago
There are much simpler standard ways to talk to a database from Rust: https://crates.io/crates/postgres/ https://crates.io/crates/postgres/ https://crates.io/crates/mysql/ https://crates.io/crates/mysql/ This is an experimental approach. It might or might not be useful, but you don't have to use it.
- brandonbloom 11y ago
  +1 It seems like the intersection of good use case for Rust and need to use SQL, will also intersect with "minimal SQL needs", hence preference for simpler libraries.
  - deleted 11y ago
    [deleted]
    - brandonbloom 11y ago
      Mentioned below where? If you're talking about query string construction performance, I'm not sure I've ever seen even a Ruby application where query string building was a bottleneck vs the network.
      - steveklabnik 11y ago
        Sorry, as you replied I had deleted my comment, because I decided I'd rather not get into an argument about this :) I will give you the link though: https://news.ycombinator.com/item?id=11045700 https://news.ycombinator.com/item?id=11045700 <- "Diesel performs 33% faster than rust-postgres, and will be competitive with if not faster than ideomatic C. "
        brandonbloom 11y ago
        Forgive me, I didn't intend to be so argumentative. I genuinely want to understand. I'm trying to figure out if there are whole categories of use cases that I just don't have any exposure to. As a side note: I keep trying Rust over and over again, and just can't get in to it. I think my brain just doesn't work that way. For my hobby project that needs super low level perf, I've moved a codebase from C, to Rust, and now to http://terralang.org/ http://terralang.org/ and I'm finally quite satisfied with how the project is going.
        rabidferret 11y ago
        It's a bit late here, but feel free to DM me in our Gitter room and I can give you a full explanation tomorrow.
        steveklabnik 11y ago
        Naw, it was my response that was more so than I wanted it to be. No worries. :) Rust focuses on "zero-cost abstractions", that is, if you had to implement a feature yourself, you couldn't do it any better. So this library, while more complex than a straightforward binding, has more features that are useful, like increased safety, while also being faster. A win-win. And very much in line with Rust's overall philosophy.
- joseph 11y ago
  That's valid, but ORMs have been pretty standard for years now too. Most mature languages have either ORMs or some database abstraction libraries, so it's good to see Rust getting those now.
  - mercurial 11y ago
    > Most mature languages have either ORMs or some database abstraction libraries And a lot of them really suck, too, because it's a hard problem. I'll take query builders or raw SQL over ORMs any day of the week.

rabidferret 11y ago

Short version: Because Rust's type system is a joy to use, and the reason I made Diesel was to try and push it forward in higher level contexts. I'm finding myself more productive in Rust than I am in any other language. Long version: http://bikeshed.fm/49 http://bikeshed.fm/49

hueving 11y ago

Workers that consume tasks and write state to a db system can easily have lots of work that rust's performance guarantees would help with.

brandonbloom 11y ago
Hopefully such systems won't be doing a fair amount of dynamic query generation... vs simple pre-baked CRUD operations.

threatofrain 11y ago

In my limited experience using both Go and Rust for hobbyist web scraping, I haven't found either language to have a significant edge in development difficulty. Go's most salient edge over Rust would be in the more numerous and mature libraries. So if Rust is not substantially easier or harder than Go, when Rust catches up to Go in the library ecosystem, I can see why people might want to use Rust. Also, it's nice to have better language support for functional strategies.

brandonbloom 11y ago
I think that Rust is substantially harder than Go. At least extrapolating from my personal experience and the 6+ highly-skilled people I've watched learn both Go and Scala simultaneously.
- kibwen 11y ago
  I wouldn't generally compare Rust against Scala, as Rust's type system is less ambitious and the language itself has far fewer concepts.
- danieldk 11y ago
  I just started learning Rust and its type system is much simpler than Scala. What makes it powerful is some well-designed somewhat orthogonal features (generics, type traits, the ownership system, algebraic data types, macros). I didn't pick up Rust as quickly as Go. However, that's not really surprising, because Go is approximately the lowest common dominator of modern statically typed languages minus generics. (In a good and bad way.) At any rate, I started learning Rust ~2 weeks ago and I am already writing small libraries, programs, etc. for my daily work. Although that took a bit more time than Go, it's also a much more pleasing language to write in (the lack or sum types or generics in Go is very annoying) and you get more safety guarantees.
  - Manishearth 11y ago
    > it's also a much more pleasing language to write in (the lack or sum types or generics in Go is very annoying) Interesting anecdote: Last year, for a course I had to write the assignments in Go. As a Rustacean, I grumbled about the lack of sum types a lot, and made various hacks via interfaces writing unidiomatic Go code to simulate them. My code design was also very Rust-y and unidiomatic. This year, I'm TAing the same course, and there's a similar assignment. One student's submission was eerily similar to my design (by now I knew that it was unidiomatic), down to the hacks used. It also contained a comment saying "missing Rust's enums" (my code contained a similar comment to explain the hacks). At first I thought it may have been copied from my code (which can be found if you're looking for it), but it was different enough in other areas. I dug a bit and found that the student was indeed a rustacean. It's rather interesting that two rustaceans used the exact same hacks and same overall design when asked to code in Go. Surprisingly, I don't miss generics too much in Go. interfaces used to make me cringe due to the extra runtime cost (since I knew Rust before learning Go, and such solutions would make me cringe in Rust), but once I got used to Go I learned to use them properly. Named interfaces are pretty easy to use and let you structure the code decently well, just like proper generics. They may have a runtime cost, but Go doesn't put as much focus on that as Rust. On the other hand, easy-to-use non-hacky sum types are something I miss from Go all the time.

mintplant 11y ago

What about Go gets you excited where Rust doesn't?

brandonbloom 11y ago
In the context of my original post: 1) garbage collection, which isn't a big deal for most server applications and 2) simplicity, where the complexity of Rust only buys me marginal performance of questionable utility for the sorts of use cases where I'd be talking to a SQL database.
- rabidferret 11y ago
  Diesel's selling point isn't actually the performance aspect. It's the safety and productivity.
  - brandonbloom 11y ago
    We're not going to settle the dynamic vs static debate in this thread, so I'll refrain from commenting on safety and productivity :-) Anyway, I don't mean to dump on your work. It seems like it's actually quite a nice implementation. I'm just questioning 1) the size of the audience and 2) Whether or not the audience who thinks they want this should actually want this.
    - pcwalton 11y ago
      If the size of your audience is your overriding concern, you shouldn't be writing your ORM in Go or Rust.
- pcwalton 11y ago
  But the sorts of use cases where you'd be talking to a SQL database do benefit from generics and ADTs. For example, generics are good to avoid having to write for loops over and over, which is pretty pointless for application code (and, I'd argue, for systems code as well--for loops are just bad). Pattern matching is nice for high-level app logic, which often has the flavor of "if A, do X; if B, do Y; else do Z". Generics enable try!, which is a lot nicer than C-style error handling. And so on.

ossreality 11y ago

I like writing Rust for more reasons that CPU efficiency. In fact, that's behind: strong memory safety, Option/no-null (probably lumps in with "strong memory safety") and of course generics and the type system at large. The speed is honestly a nice benefit. (I'm not being sassy, I don't have speed intensive applications and still reach for Rust).

sedatk 11y ago

memory is a critical resource for scalability and gc's are not good at it.

jeffdavis 11y ago

I think it's hard to tell whether a language (by itself, not counting the libraries) will be good for something until you try. Rust has enough going on that some creative people might find some really useful things it can do in surprising spaces. Think about JavaScript and Node.js. Who would have predicted that?

pcwalton 11y ago

Even if we were to assume that GC is better than manual memory management for servers (something I think is not really true), this presupposes that the non-memory-management-related parts of Go's type system are better than those of Rust. I disagree with that for many reasons.

Keats 11y ago

For me Rust compiler and type system is much much better than the one in Go. Rust is still very far from Go right now though but I like the "if it compile, it works" which is not a certainty in Go.