MySqlConnector

MySqlConnector (the most popular .NET library for MySQL, and the one that I authored) has supported protocol compression for many years: https://github.com/mysql-net/MySqlConnector/issues/31.

> I kept technical notes about the protocol, to serve as a future reference for myself and for other developers. As someone who's written a MySQL client (in C#: https://github.com/mysql-net/MySqlConnector), I'd be very interested to see your notes. Are they available anywhere, or were they the confidential IP of your client? > Unsurprisingly, bugs were uncovered every time a new client was added. I've faced the same thing, from a client perspective. Every time a new server is tested (MySQL, MariaDB, Amazon Aurora, Azure Database for MySQL, etc.), I find slightly different interpretations of the protocol and have to accommodate them.

I have had the pleasure of contributing to a couple different networked drivers with very talented maintainers that I like to use as references. One supports a wide array of Framework versions and has both Sync and Async I/O, as it must to implement the ADO.NET database driver interfaces. Reading the internals really highlight the way that .NET has evolved over the years and what must be done in each target version to maximize performance: https://github.com/mysql-net/MySqlConnector The other supports .NET 6 only with Async I/O only. This support policy seems to be the way that "modern" .NET development is headed, as .NET 6 will be the floor for LTS .NET (formerly .NET Core) releases in a few months. Async APIs only greatly simplify development, and make it simpler to remain performant when targeting WASM. https://github.com/Cysharp/Alte

MySqlConnector (C# - https://github.com/mysql-net/MySqlConnector) uses "smoke and mirrors" for the "text" protocol (because MySQL Server has no way to send parameters as part of a `COM_QUERY` packet, https://dev.mysql.com/doc/internals/en/com-query.html) and true parameters for the "binary" protocol, which does (https://dev.mysql.com/doc/internals/en/com-stmt-execute.html). Every MySQL client needs to do something similar, due to the design of the MySQL protocol.

I'm the author of what you might call the "new" MySQL ADO.NET library: https://github.com/mysql-net/MySqlConnector I agree with your impression that developers of the other library don't seem to be "plugged in to" the .NET ecosystem. As an independent developer (not affiliated with Oracle or Microsoft), I've been able to influence GitHub PRs that shape the ADO.NET API for .NET 6.0, just by showing up and contributing; I haven't seen anyone from the Oracle MySQL team participating. Meanwhile, they violate basic principles of the .NET Framework Design Guidelines that have been around for over a decade (https://docs.microsoft.com/en-us/dotnet/standard/design-guid...), which makes their library feel alien to a .NET programmer (regardless of the quality issues it might have).

While the second and third problems sound specific to Go's `database/sql` API, the first problem (server-closed connections) is an issue any MySQL client library (that implements connection pooling) has to deal with. My .NET MySQL connector (https://github.com/mysql-net/MySqlConnector) "solves" it at the MySQL level by sending a PING packet, but as the post points out, this adds extra latency. The TCP-based approach of performing a non-blocking read sounds like a much better approach; I'm glad the author shared this, and I want to see if that technique can also be implemented in MySqlConnector: https://github.com/mysql-net/MySqlConnector/issues/821.

I do not know of a good Cross DB solution. It may be more elegant to check specific exception types for the DBMSs that you do use. For example, MySQL would be: https://github.com/mysql-net/MySqlConnector/blob/master/src/... Check that MySqlException.Number == 1062 for Duplicate entry. Add one check per DBMS that you use.

> You don't need to build two library APIs. You can just build an Async method as the default implementation then have a blocking call to that as the synchronous method This can lead to a nasty problem: Thread Pool Starvation. I contribute to MySqlConnector, an MIT Licensed MySql driver for .NET that implements truly Asynchronous I/O. We did this at first, but had to do a large refactor because we hit Thread Pool Starvation in our high concurrency performance tests. Here's the original issue: https://github.com/mysql-net/MySqlConnector/issues/62 Stephen Toub has a pretty good article explaining why you shouldn't do "Sync over Async": https://blogs.msdn.microsoft.com/pfxteam/2012/04/13/should-i...

I've developed a fully async, independent, MIT-licensed MySQL ADO.NET provider for .NET and .NET Core: https://github.com/mysql-net/MySqlConnector