diesel_async VS rust-postgres

So I want to use diesel_async in my web backend.

The already linked discussion from last time already contains a lot of information about this. Diesel itself does not provide async operations and that will likely remain that way for a foreseeable future. At least my preferred solution is to keep async support in a separate crate. A prototype for this is currently available here. Keep in mind that this is not released yet, so there might be bugs everywhere. I plan to cut a first release of this crate after the final release of diesel 2.0, which means hopefully soon. As for ETA's: I generally do not give any ETA's for releases, as this is currently a free time project for me.

So, diesel is an ORM that tries to take full advantage of rust's typing expressivity to allow for statically checked, and fast, queries. I absolutely loved it when trying it out the first time.

i don't see why you or anyone else would consider it too big of an issue that Diesel doesn't have async. For those who really want async diesel right now, the author already released diesel_async as a stop-gap solution, but even without that there's nothing wrong with using spawn_blocking. It feels worse than it really is to use blocking thread pools; until io_uring is a thing, there's no real getting around the necessity of threads being blocked for I/O and so adding async to the mix doesn't magically make things faster.

As for now there is an prototype available here. It's technically feature complete, but depends on a unpublished diesel version + has some remaining bugs with certain mysql versions. If that is fixed I will likely publish a first alpha version officially. That can take same time because that's a second large project that needs maintenance time beside diesel itself and that's quite a lot to do in my free time. You can support this work by sponsoring me on github

Async support for diesel currently lives in a separate repository as there are language level blocking issues for publishing a version of this crate where we could commit to a stable release at all. See the corresponding diesel issue for details.

https://github.com/weiznich/diesel_async tho'.

Weiznich (the maintainer of Diesel) has created an experimental async version of the diesel Connection and RunQueryDsl traits, which should help with ease-of-use for Diesel within async contexts. It is not yet published on crates, but you can find it here: https://github.com/weiznich/diesel_async

For C there should be good options.

For Rust it doesn't appear that well-supported.

A very simple approach is to poll for changes using `pg_logical_slot_get_changes()` - that should work with any driver. That's what I used for my initial experimentation, before switching over to the streaming replication protocol for better performance.

The streaming replication protocol is not that complicated, but currently you'll have to handle some of the low-level protocol yourself, or work with some very experimental implementations. There's a project to help get you started at [1], and some more discussion at [2].

For the logical decoder, wal2json is quite nice to experiment with, but I've found pgoutput is not that complicated and gives you something closer to the raw data.

[1]: https://github.com/seddonm1/logicaldecoding/

[2]: https://github.com/sfackler/rust-postgres/issues/116

This is a bit of a rant so please bear with me. I wrote a small utility program a long time ago that used this version of the postgres crate

En este post aprendermos a usar Rust, Tonic y la crate gRPC, y implementaremos un CRUD con Postgresql database.

I can understand that this can be frustrating and I know that the situation there is not ideal for diesel. There are certainly things to improve there by either providing a bundling support which builds the native library as part of the normal build process or by implementing a pure rust connection implementation. Both is possible with diesel, but requires some work. At least the pure rust connection implementation is something that can be provided by a third party crate now with upcoming diesel 2.0 release. If you are interested in that checkout this and this issue. As for the bundling support: This requires changes in the mysqlclient-sys and pq-sys crates. Again help there is welcome. In the end it makes me sad that some people have repeating decided that a solution to this problem is to write just another crate instead of helping to fix these issues. This just results in everyone have more work to do, as there are now two non-perfect solutions instead of having one slightly improved solution.

We created this little library to have a fully native type for Postgres Numerics with the rust-postgres (https://github.com/sfackler/rust-postgres) library.

The problem with a crate like postgres is that you have to define the types of the query at compile-time. And if you use the simple query protocol in postgres, you just get a bunch of strings, i.e. no proper typing at all. However, for maximal flexibility arbitrary queries should work in pigeon, without knowing the database schema.

Some nifty things about usual: - It's a generic wrapper over any SQL "row" object. The first implementation that's provided is for tokio-postgres, but traits are available to implement over whatever you'd like. - It provides static typing for partial queries. That is, it supports fetching a subset of fields from a row and makes a unique type for the return value. This gives you some neat-o type safety like this:

In this post, we will learn how to use Rust Tonic gRPC crate. We will learn how to implement CRUD with Postgresql database.

(see: https://github.com/sfackler/rust-postgres/blob/e15c9b1415f69821799f1370246581c1600a6196/postgres-protocol/src/types/mod.rs#L137)