Summary of database isolation levels

Summary of different database isolation levels

I’ve been always a bit confused about different isolation levels on databases. So I spent a bit of time going through them and summarize it in a post. This is both for myself and also hopefully will help others looking for similar information as well.

In this post we’ll talk about:

  • Meaning of different isolation levels - read committed, repeatable reads, snapshot isolation, serializable
  • How they use locks inside transactions
  • How they affect performance

typeof(TSecret) - the secret magic behind .NET generics

How typeof(T) works in .NET generics

typeof(TSecret) - the secret magic behind .NET generics

In last post we’ve talked about how .NET does code sharing for reference types. This time let’s take a look at how typeof(T) does its black magic.

In particular, how does the code knows what typeof(T) is, in the presence of code sharing?

Obviously if there is no code sharing at all, each method instantiation are different and the code would be instantiated with the correct typeof(T) code where T is a real type, it obviously would “just work”.

Before we dive into the implementation, let’s take a first crack at this problem and see what are the challenges.

Does Go need async/await?

Does the go language need async/await support?

Recently I’ve been spending a bit of time playing with Go language. Coming from a C++ and C# background, I’ve been wondering what does C# async await (C++ coroutines, or node.js await/promise - pick your choice), would look like in Go.

It turns out go does not need async/await - every thing can be synchronous by default.

Let me explain why I arrived at this conclusion.

But before that, let’s take a look at why we need the async/await in the first place.

Top secret .NET handles - Part 2 - Ref-Counted handles

Top secret .NET handles - Part 2 - Ref-Counted handles

Last time we talked about .NET dependent handle. It is a handle that promotes secondary if primary is promoted - as if there is a imaginary reference between them. This time let’s take a look at another secret handle - ref-counted handle. A ref-counted handle is a special handle that will become either strong or weak depending on the ref count. It’s only used in COM interop today internally in the CLR.

You can find its definition in gcinterface.h

     * Refcounted handles are handles that behave as strong handles while the
     * refcount on them is greater than 0 and behave as weak handles otherwise.
     * N.B. These are currently NOT general purpose.
     *      The implementation is tied to COM Interop.


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