Comment by phkahler

7 hours ago

>> But had they written their software in C, they wouldn't have needed to do any conversion at all. It means they could have titled the article "How we lowered the performance penalty of using Rust".

That's not really fair. The library was doing serialization/deserialization which was poor design choice from a performance perspective. They just made a more sane API that doesn't do all that extra work. It might best be titles "replacing protobuf with a normal API to go 5 times faster."

BTW what makes you think writing their end in C would yield even higher performance?

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phkahler

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GuB-42  5 hours ago

> BTW what makes you think writing their end in C would yield even higher performance?

C is not inherently faster, you are right about that.

But what I understand is that the library they use works with data structures that are designed to be used in a C-like language, and are presumably full of raw pointers. These are not ideal for working in Rust, instead, presumably, they wrote their own data model in Rust fashion, which means that now, they need to make a conversion, which is obviously slower than doing nothing.

They probably could have worked with the C structures directly, resulting in code that could be as fast as C, but that wouldn't make for great Rust code. In the end, they chose the compromise of speeding up conversion.

Also, the use of Protobuf may be a poor choice from a performance perspective, but it is a good choice for portability, it allows them to support plenty of languages for cheaper, and Rust was just one among others. The PgDog team gave Rust and their specific application special treatment.