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Why I'm Building a Database Engine in C#

47 points

by vyrotek

3 hours ago

| past

| 9 comments

| nockawa.github.io

| HN

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benterix

2 hours ago

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> JIT warmup is real. The first call to any method pays the compilation cost. In a database engine, the first transaction after startup shouldn’t be 100x slower than the steady state.

Correct me if I'm wrong but isn't it what aot was supposed to solve?

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nycdotnet

7 minutes ago

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In the section “Hardware-accelerated WAL checksums” he explains how the JIT compiles away the hardware support stuff depending on the exact capabilities of the system its on. With AOT you don’t get this - it’s way more coarse like x64 vs ARM

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landl0rd

1 hour ago

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AOT is a little fussy in real-world usage particularly for things like reflection. You can probably force it to work but it may make your code much uglier.

Span<T> is more important for performance TBH JIT warmup isn't a huge issue for a long-running process

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CharlieDigital

1 hour ago

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    > ...but it may make your code much uglier

Flip side is that if you use more source generation, it may end up making the code more terse/"prettier" where it matters and avoid the reflection hit.

AI agents seem fairly good at generating source generators so there doesn't seem to be a reason to not use them.

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orphea

24 minutes ago

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What's fussy about AOT and reflection?

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sebazzz

40 minutes ago

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With UnsafeAccessor you can often avoid reflection.

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tracker1

3 hours ago

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Also worth mentioning are VeloxDB and RavenDB, both written in C#. TBF, I haven't used any of them... but aware they exist.

C# is pretty powerful and capable of lower level usage, such as in the examples given... not to mention a pretty nice interop with C-style libraries. It looks like the intent here might be a custom database engine for service integrations... not necessarily a full rdbms in and of itself.

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nitwit005

1 hour ago

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I would be less worried about the GC pause, than the need to reserve some memory for garbage collection. Any reduction in available memory is going to tend to mean a hit to performance.

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zerr

1 hour ago

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I'd say modern C++ is high level and ergonomic enough to stop considering any language with a GC.

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drfloyd51

1 hour ago

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Does C++ have build in memory management now?

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alex7o

1 hour ago

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That seems great, I have seen a few similar dbs written in java that say the same thing, that when written correctly you can get the perf very close to C, but at that point you are just writing C with a different syntax. You don't win on any in the security guarantees, so at that point can we just not build everything in wasm and then we can interface it from both dotnet and the jvm?

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DeathArrow

1 hour ago

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I wonder why he didn't use AOT compiling if he's worried about JIT warmup.

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topspin

1 hour ago

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It wasn't discussed, so we're left to speculate. If I had to guess, I imagine that the .NET JIT has actual benefits: the variety of architectures has gotten enormous and JIT is likely a performance win after warmup.

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jaen

3 hours ago

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C# is a great language with almost unlimited power and great ergonomics (as the article shows), but the .NET CLR (runtime) is a bit overcomplicated with a distinct "Java smell", and packaging and distribution is still meh.

If they could make the developer experience similar to Go, it would rule the world...

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Rohansi

2 hours ago

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> If they could make the developer experience similar to Go, it would rule the world...

You can already AOT compile .NET software to an executable to run on whichever platform you need, just like Go.

Libraries need to be published into a package manager (NuGet) which is more friction than just importing from Git repos but it's not that bad.

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hnrodey

1 hour ago

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AOT is not a panacea and comes with some restrictions/trade-offs that need understood before depending on it in production.

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landl0rd

1 hour ago

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I actually really like the CLR developer experience next to java ngl. I reach for C# in lieu of java (less J2EE SingletonBeanFactoryManagerInstance slop) but particularly F# is pretty nice to use. Haskell has bad tooling, OCaml is getting better thanks to JaneStreet (and if OxCaml gets wide adoption unboxed types are a big perf win) but if nothing else lack of a Rider-esque debugger is just a big time sink.

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karmakaze

3 hours ago

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I drank the Go kool-aid, then tried to do some high performance things the Go way: didn't work (channels are slow) and I got over it. Still think Go is great for web backends and the like with production grade stdlib.

Great post with details, not a I'm vibe coding...

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benterix

2 hours ago

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> tried to do some high performance things the Go way: didn't work (channels are slow) and I got over it.

What did you choose instead?

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kerblang

26 minutes ago

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Am amused that someone feels compelled to justify writing a db in C#. Such conscientiousness!

I'm not sure authors of Cassandra, ElasticSearch, MongoDB (and more...?) ever had the slightest twinge of uncertainty about whether a managed memory env would cause far more problems than it fixed, even with less native tooling than in C#. Java bros DGAF

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achillesheels

1 hour ago

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You do you.