280 posts tagged with "C#"

Plain-text logs are nice to read, and hard for a log tool to search. AddJsonConsole writes one JSON object per entry, with each value in a field of its own. Keep plain text in Development, and use JSON everywhere else.

By default, ASP.NET Core reads a request body of up to about 28.6 MB. An API that takes small JSON documents has no use for that, and lowering it means a huge body gets turned away before your code spends any time on it.

A rate limit per client address stops one caller from using up what's meant for everyone. ASP.NET Core has this built in, as a fixed window for each address. It takes a few lines, plus a little more to tell the client when to come back.

A concurrency limit lets a fixed number of requests run at once, and makes the rest wait or go away. It's different from a rate limit, which counts requests over time. It's also what kept my API alive when a burst would otherwise have crashed it.

Pooled connections stay open after you close them, usually for good reason. If you need them gone, MySqlConnection has two static methods. You'll rarely need them, so here's how they behave, and when you would.

Connect Timeout is how long MySql.Data waits for a connection, and it defaults to 15 seconds. That looks harmless until retries multiply it. An unreachable server held one request for 64 seconds in my test, and a smaller value brought that to 24.

Pooled connections can live for as long as the app runs, which is a problem if the server behind them changes. Connection Lifetime retires them once they're old enough, so new ones find the new server. I timed exactly when it happens.

After a burst, a connection pool holds a lot of open connections. How long do they stay? I opened 8, closed them, and counted them every minute: they go after about 3 minutes, down to Minimum Pool Size.

Maximum Pool Size defaults to 100, and MySQL's max_connections to 151. So two copies of an app can ask for more than the server allows, and more requests than the pool holds can end the whole process. Here's how I picked a number, from measurements.

Opening a MySQL connection takes many round trips: TCP, TLS, then signing in. So MySql.Data keeps connections open after you close them, and hands them out again. A few lines of C# let you watch it work, and see what it saves.