When designing a new data format, it is important to remember in what environment we’ll operate in, what are the requirements and what type of scenarios we’ll face. With RavenDB, we are talking about the internal storage format, so it isn’t something that is available externally. That means that we don’t have to worry about interchange with anything, that frees ...

JSON is a really simple format. It make it very easy to work with it, interchange it, read it, etc. Here is the full JSON format definition: object = {} | { members } members = pair | pair, members pair = string : value array = [] | [ elements ] elements = value | value , elements value ...

In my previous post I showed the following code, and asked what the bug was, and what the implications of that would be. class Program { private Timer nextcheck; public event EventHandler ServerSigFailed; static void Main(string[] args) { var program = new Program(); if(program.ValidateServerSig() == false) return; program.DoOtherStuff(); } public bool ValidateServerSig() { nextcheck = new Timer(state => ValidateServerSig()); var ...

The following code contains a bug, can you spot it? class Program { private Timer nextcheck; public event EventHandler ServerSigFailed; static void Main(string[] args) { var program = new Program(); if(program.ValidateServerSig() == false) return; program.DoOtherStuff(); } public bool ValidateServerSig() { nextcheck = new Timer(state => ValidateServerSig()); var response = DoRequest("http://remote-srv/signature"); if(response.Failed) { var copy = ServerSigFailed; if(copy!=null) copy(this, EventArgs.Empty); return ...

Here is the full method that we refactored: public void ReturnMemory(byte* pointer) { var memoryDataForPointer = GetMemoryDataForPointer(pointer); _freeSegments.AddOrUpdate(memoryDataForPointer.SizeInBytes, x => { var newQueue = new ConcurrentStack<AllocatedMemoryData>(); newQueue.Push(memoryDataForPointer); return newQueue; }, (x, queue) => { queue.Push(memoryDataForPointer); return queue; }); } And here is the allocation map for this method: public unsafe void ReturnMemory(byte* pointer) { <>c__DisplayClass9_0 CS$<>8__locals0 = new <>c__DisplayClass9_0(); CS$<>8__locals0.memoryDataForPointer ...

In a recent code review, I had modified the following code:   _freeSegments.AddOrUpdate(memoryDataForPointer.SizeInBytes, x => { var newQueue = new ConcurrentQueue<AllocatedMemoryData>>(); newQueue.Enqueue(memoryDataForPointer); return newQueue; }, (x, queue) => { queue.Enqueue(memoryDataForPointer); return queue; }); Into this code: var q = _freeSegments.GetOrAdd(memoryDataForPointer.SizeInBytes, size => new ConcurrentQueue<AllocatedMemoryData>()); q.Enqueue(memoryDataForPointer); Can you tell me why? Reference: Code review challenge – The concurrent dictionary refactoring from ...

We require all candidates to do a coding test before we invite them to an interview. The purpose of the coding test is to get some idea about the way the person thinks, and to see what they can do. Often, we don’t really care about the actual solution that was sent, because the point isn’t to solve the problem ...

A customer called with a major issue, on a customer machine, a particular operation took too long. In fact, it takes quite a bit more than too long. Instead of the few milliseconds or (at worst, seconds), the customer saw a value in the many minutes. At first, we narrowed it down to an extreme load on the indexing engine. ...

Every programmer knows that input validation is important for good application behavior. If you aren’t validating the input, you will get… interesting behavior, to say the least. The problem is that what developers generally don’t consider is that the system configuration is also users’ input, and it should be treated with suspicion. It can be something as obvious as a ...

I’m doing some work to refactor a complex piece of code, and I have a piece of memory that is allocated, then accessed via a struct pointer. This piece of code gets called a lot, so I wondered about the tradeoff of holding a pointer that is already casted to the right struct pointer vs the cost of another pointer ...