Intro

I had this situation where an application that was running in production was getting bigger and bigger until it would devour all memory. I had to fix the problem, but how could I identify the cause? Running it on my computer wouldn't lead to the same increase in memory, what I wanted to see was why a simple web API would take 6Gb in memory and keep growing.

The process is simple enough:

1. Get a memory dump from the running process
2. Analyze the memory dump

While this post relates specifically to process memory dumps, one can get whole memory dumps and analyze those. There are two types of process memory dump formats: mini and full. I will be talking about the full format.

Fortunately, for our process, there are only two steps. Unfortunately, both are fraught with problems. Let's go through each.

Getting a memory dump from a running process

Apparently that is as simple as opening Task Manager, right clicking on the running process in the Details tab and selecting Create dump file. However, what this does is suspend the process and then copy all of its memory in a file in %AppData%/Local/Temp/[name of process].dmp. If the process is being watched or some other issue occur, the dumping will fail. Personally, I couldn't dump anything over 2Gb when I was trying to get the info from w3wp.exe (the IIS process) as the process would restart.

There are a lot of other ways of getting a process memory dump, including crash dumps, periodic dumps, event driven dumps. ProcDump, one of the utilities in the free SysInternals suite, can do all of those. The Windows Error Reporting (WER) system also generates dumps for faulty or unresponsive application or kernel. Other options for collecting a dump are userdum.exep, Windows Debugger (ntsd or windbg). Process Explorer, of course, can create two types of memory dumps for a process: mini and full.

Analyzing a process memory dump

This is where it gets tricky. What you would like is something that opens the file and shows a nice interactive interface explaining exactly what hogs your memory. Visual Studio does that, but only the Ultimate version gives you the memory analysis option. dotMemory from JetBrains is great, but it also costs a lot of money.

My personal experience was using dotMemory in the five days in which it is free and it was as seamless as I would have wanted: I opened the file, it showed me a pie graph with what objects were hogging my memory, I clicked on them, looked where and how they were stored and even what paths could be taken to create those instances. It was beautiful.

Another option is SciTech's .NET Memory Profiler, but it is also rather expensive. I am sure RedGate has something, too, but their trials are way to intrusive for me to download.

I have been looking for free alternatives and frankly all I could find is WinDBG, which is included in Windows Debugging Tools.

Windows Debugger is the name of the software. It is a very basic tool, but there are visualizers which use it to show information. One of them is MemoScope, which appears unmaintained at the moment and is kind of weird looking, but it works. Unfortunately, it doesn't even come close to what dotMemory was showing me. If analyzing a random .NET app dump showed that the biggest memory usage was coming from MainWindow (makes sense) which then had a lvItems that held most of memory (it was a ListView with a lot of data), WinDbg and therefore MemoScope show the biggest usage comes from arrays of bytes. And it also makes sense, physically, but there is no logical context. A step by step memory profiling guide using WinDbg can be found here.

Conclusion

I am biased towards JetBrains software, which is usually amazing, although I haven't used it a quite a while because their obnoxious licensing system (you basically rent the software). I loved how quickly I got to the problem I had with dotMemory. .NET Memory Profiler from SciTech is way cheaper and seems to point in the right direction, but doesn't really compare in terms of quality. Anything else I've tried was quite subpar.

Doing it yourself

As they say, if you want to do something right, you gotta do it yourself.

There is a Windows API called MiniDumpWriteDump that you can use programatically to create the dumps. However, as you've seen, that's not the problem, the dump analysis is.

And it's hard to find anything that is not very deep and complicated. Memory dumps are usually analysed for forensic reasons. There are specialists who have written scores of books on memory dump analysis. What's worse, most people focus on crash dumps, with memory leak analysis usually done while debugging an application.

I certainly don't have the time to work on a tool to help me with this particular issue. I barely had the time to look for existing tools. But if you, guys, can add information to this blog post, I am sure it will help a lot of people going through the same thing.

Pretty Pictures

I didn't find a nice way of putting the images in the post's text, I am adding them here.

MemoryCache has a really strange behavior where all of a sudden, without any warning or exception, it stops caching. You use Set or Add, it doesn't matter. It returns true for Add, it throws no error for Set, but the cache stubbornly remains empty. This behavior can be replicated easily by running this line:

MemoryCache.Default.Dispose();

From that moment on, MemoryCache.Default will not cache anything anymore.

Of course, you will say, why the hell would you dispose the default object? First of all, why give me the option? It's not like I can set the Default instance after I dispose it, so this breaks a lot of things. Second of all, why pretend to continue to be working when in fact it is not? Most disposable classes throw exceptions if they are used after being disposed. And third of all, it might not be you who does the disposing.

In my case, I was trying to be a good boy and declare all my dependencies upfront. I was using StructureMap as a IoC framework and for my class that was using a MemoryCache I declared a constructor parameter of the basest type I could: ObjectCache. Then I registered MemoryCache.Default as the instance used when needing an ObjectCache. The problem is that each unit test would initialize and tear down the StructureMap container and it would take all the instances used that implement IDisposable and dispose them, including our friend MemoryCache.Default. As I couldn't find a simple way to tell StructureMap to not dispose the object, I had to create a MemoryCacheWrapper that implemented ObjectCache and was NOT IDisposable and was using MemoryCache.Default for all methods and use that as the singleton instance for an ObjectCache in StructureMap.

If you are working with a .NET version prior to .NET 4.5, you may encounter the same issue with a bug in .NET: MemoryCache Empty : Returns null after being set

This guy can write! I mean, Peter Brannen is writing about paleontology and climate change and the words just sing to you, make you see worlds that we actually know very little about and feel for ammonoids like there would be the cutest kittens, looking at you with big eyes and begging not to get extinct. As someone who wants to write himself someday, I really hate this guy. He is that good.

That being said, The Ends of the World is a book about the major extinctions in Earth's history, their causes and how they relate to our present lives. It's a captivating read, evoking lost worlds and very carefully analyzing how they disappeared and why. There is humor, drama, interesting interviews with fascinating people. Dinosaurs? Puh-lease. This takes you back to the good old days of the Ediacaran and slowly brings you around our time and even speculates on what could come after us, the hubris filled species that, geologically speaking, was barely born yesterday - or a few seconds ago, depending on how you measure it - and has the chance to outshine all the other species that came, ruled and went.

There is no way I can do it justice other than to say that I loved the book. In itself it's a summary of life on Earth so summarizing it myself would be pointless. I highly recommend it.

Here is the author, presenting his book at Google Talks:

You are trying to install an application and in the detailed log you get something like this:

InstallSqlData:  Error 0x8007007a: Failed to copy SqlScript.Script: SqlWithWindowsAuthUpv2.9.5UpdateGetInstallJobBuildByInstallJobBuildIdScript

or

InstallSqlData:  Error 0x8007007a: failed to read SqlScripts table

For me it was related to the length of an <sql:SqlScript> tag Id property. If you are trying to use more than 55 characters for the BinaryKey property, you get a build error that you should use a max of 55 characters. For the Id you get no such warning, but instead it fails on install.

I hope it helps people (I lost two hours figuring it out).

What's Expected of Us and Others is a collection of stories by Ted Chiang including

• Exhalation
• Dacey's Patent Automatic Nanny
• The Truth of Fact, the Truth of Feeling
• The Lifecycle of Software Objects
• What's Expected of Us
• The Merchant and the Alchemist's Gate
• The Great Silence

All the stories are speculative fiction, their subjects related to the meaning of life and evolution in relation to technology. His writing style is direct, unsophisticated, often based on first person perspective and dialogue. It's the ideas that he is exploring where he spends most of his efforts. All in all a nice collection of sci-fi, but not something extraordinary in nature.

Sometimes we need to execute an async method synchronously. And before you bristle up and try to deny it think of the following scenarios:

• event handlers are by default synchronous
• third party software might require you to implement a synchronous method (like a lot of Microsoft code, like Windows services)

All I want is to take public async Task ExecuteStuff(param1) and run it with ExecuteSynchronously(ExecuteStuff, param1).

"What's the problem?", you might ask, "Just use SomeMethod().Result instead of await SomeMethod()". Well, it doesn't work because of the dreaded deadlock (a dreadlock). Here is an excerpt of the .Net C# code for Task<T>.InternalWait (used by Result and Wait):

// Alert a listening debugger that we can't make forward progress unless it slips threads.
// We call NOCTD for two reasons:
//    1. If the task runs on another thread, then we'll be blocked here indefinitely.
//    2. If the task runs inline but takes some time to complete, it will suffer ThreadAbort with possible state corruption,
//       and it is best to prevent this unless the user explicitly asks to view the value with thread-slipping enabled.
Debugger.NotifyOfCrossThreadDependency();

As you can see, it only warns the debugger, it doesn't crash it just freezes. And this is just in case it catches the problem at all.

What about other options? Task has a method called RunSynchronously, it should work, right? What about Task<T>.GetAwaiter().GetResult() ? What about .ConfigureAwait(false)? In my experience all of these caused deadlocks.

Now, I am giving you two options, one that I tried and works and one that I found on a Microsoft forum. I don't have the time and brain power to understand how this all works behind the scenes, so I am asking for assistance in telling me why this works and other things do not.

First of all, two sets of extensions methods I use to execute synchronously an async method or func:

/// <summary>
/// Execute an async function synchronously
/// </summary>
public static TResult ExecuteSynchronously<TResult>(this Func<Task<TResult>> asyncMethod)
{
    TResult result = default(TResult);
    Task.Run(async () => result = await asyncMethod()).Wait();
    return result;
}
 
/// <summary>
/// Execute an async function synchronously
/// </summary>
public static TResult ExecuteSynchronously<TResult, TParam1>(this Func<TParam1, Task<TResult>> asyncMethod, TParam1 t1)
{
    TResult result = default(TResult);
    Task.Run(async () => result = await asyncMethod(t1)).Wait();
    return result;
}
 
/// <summary>
/// Execute an async function synchronously
/// </summary>
public static void ExecuteSynchronously(this Func<Task> asyncMethod)
{
    Task.Run(async () => await asyncMethod()).Wait();
}
 
/// <summary>
/// Execute an async function synchronously
/// </summary>
public static void ExecuteSynchronously<TParam1>(this Func<TParam1,Task> asyncMethod, TParam1 t1)
{
    Task.Run(async () => await asyncMethod(t1)).Wait();
}

I know, the ones returning a result would probably be better as return Task.Run(...).Result or even Task.Run(...).GetAwaiter().GetResult(), but I didn't want to take any chances. Because of how the compiler works, you can't really use them as extension methods like SomeMethod.ExecuteSynchronously(param1) unless SomeMethod is a variable defined as Func<TParam1, TResult>. Instead you must use them like a normal static method: MethodExtensions.ExecuteSynchronously(SomeMethod, param1).

Second is the solution for this proposed by slang25 :

public static T ExecuteSynchronously<T>(Func<Task<T>> taskFunc)
{
    var capturedContext = SynchronizationContext.Current;
    try {
        SynchronizationContext.SetSynchronizationContext(null);
        return taskFunc.Invoke().GetAwaiter().GetResult();
    }
    finally {
        SynchronizationContext.SetSynchronizationContext(capturedContext);
    }
}

I haven't tried this, so I can only say that it looks OK.

A third options, I am told, works by configuring every await to run with ConfigureAwait(false). There is a NuGet package that does this for you. Again, untried.

It is said that the great theory of relativity of Einstein's doesn't apply to things moving slowly. Today I realized that is not true. There is a direct relationship between space and time and speed affects space, so it must affect time. Here is a practical example: a car moves faster than a person walking, so its speed makes distance shrink relative to time. Inversely, that means that it makes time expand, become more expensive, from the car's point of view.

That is why, when you see a car approaching and you have the option of walking in front of it forcing it to stop, you wait, because the driver's time is more expensive than yours. Stopping the car and wasting time would impact him much more than it would you. It also has the side effect that it saves your life if the car doesn't stop for some reason.

Just a thought.

The Romanian language has a word: deștept. It means smart, but it leans into knowledgeable, so it means both "knowing things" and "thinking fast". There is no relation to wisdom and this is the case in other languages as well. Sometimes wise is used to denote knowledgeable, yet I don't think they are related. While to know things means to be able to recall things you have learned, wisdom, I've come to realize, means to understand what little you know. Someone might be wise and know very little and think rather slowly. Wisdom is the maturation of the soul, like a well kept wine it provides subtle flavors.

Even a superficial and forgetful person as myself can gain wisdom in time. It is important to note this, because as people get older, stuck between that limit of usefulness and the onset of senility, we tend to dismiss them, flaunt our new found (and invented) knowledge to their faces, ignoring a very important aspect of their evolution: wisdom. Sure, their wisdom might not apply to your field or need, but even if it were, are you acknowledging it?

Just a thought.

As far as I can see, Ted Chiang's Tower of Babylon is the first thing he published. It's a short story (that you can find online for free) about two workers climbing the tower of Babylon to dig through the Vault of Heaven.

In this story the tower is not struck down and the people have been working on the tower for centuries. It's a fun read, although not particularly funny or captivating. It does show Chiang's penchant for speculative fiction, though. I liked it, but not enough for four stars and three seems too little. Read it. It's short and I don't want to write more about it than it is itself in length :)

I am writing this post to let people know why a particular annoying problem happens on Windows 10 with regards to notifications. Before it was called "Focus Assist" it was called "Quiet hours" and you would turn it on to make annoying notifications not show while you were working or playing. After a Windows update, Microsoft renamed it to Focus Assist and turned it into a more complex setting, rather than on/off. But then the problems appeared.

Symptoms:

• Notification traybar bubble is white (outline filled) and going over with the mouse it either says nothing or says "1 notification"
• When you click on it, it shows no notifications and the bubble remains filled
• If you right-click it, none of the options in the Focus Assist menu seem to be working and none are checked
• If you go to Settings and click on Focus Assist, Settings crashes with no error message
• You also may have Avast antivirus installed

People have been tracking the problem on this Microsoft forum: Settings app crashes accessing "Focus Assist" settings and here are our findings:

1. The problem comes from Avast (or some other source) turning off the Windows Push Notifications User Service. Turning it on, restores Focus Assist functionality.
2. Avast has something called Silent Mode, which many people use because Avast started pushing all these annoying messages lately
3. In the Avast configuration (go to Menu , Settings, Components, scroll down the page until Performance, Do Not Disturb Mode, then Customize) there is a setting called "Silence notifications from 3rd-party apps". By default it's on. Turn it off and Avast will no longer kill the service
4. If the cause of this behavior is different from Avast's silent mode, let me know. An immediate fix is to go to Services (services.msc), scroll down to Windows Push Notifications User Service (followed by underscore and some meaningless numbers and letters) and make sure it is started.

Hope this helps.

A Conjuring of Light ends the Shades of Magic trilogy, although apparently a new trilogy set in the same universe is on its way. All the major threads are closed, although some of them felt a little forced and some of the drama was clearly artificial. But at least it all ends, which is one of the major reasons I read this book, only to see how Victoria Schwab's characters will end up.

I felt that this was the more ambitious volume of the three in the series, with all three Antari having to interact, with foreign dignitaries stuck in the royal palace while it was under siege from a demented magical creature who believed itself a god, with ties with families and past revealed, with new places and new magic. However, the book was quite inconsistent. For example, there is a plan to use a spell to seal the god in a body. When it is inside one, they forget about it and fight him with knives and fire and what not. There is a spell that could restore Kell's memory. He wonders if he should use it, then we forget about it. As for Grey London (ours) and Black London (the one where the creature originated), they are completely ignored.

The personalities of the characters also change a lot, with everyone acting brave and selfless (sometimes to stupidity) as if forgetting we are talking about a ruthless street thief, a killer turned sociopath by years of torture and so on. To me it seemed as if the author wanted a tough story, but she couldn't help turning it into a classic hero quest with a happy ending.

Bottom line: I had fun reading the series, but I won't continue with the next trilogy. It's not bad, but it's not above average either.

Kind of obvious, but I wanted to make it clear and to remember it for the future. You want to make something appear or not based on a toggle button, usually done by adding a click handler on an element with some code to determine what happens. But you can do it with HTML and CSS only by using the label element pointing to a hidden checkbox with its for attribute. Example:

Toggle me!   I have been toggled!

Here is the HTML and CSS for it:

<style>
     /*  you have to use a caption element instead of a control element inside the label, so a button would not work and we use a span to look like a button */
     .button {
       border: solid 1px gray;
       padding: 5px;
       display: inline-block;
       user-select: none;
       cursor: pointer;
     }
 
     /* the element after the unchecked checkbox is visible or not based on the status of the checkbox */
     #chkState + span { display: none; }
     #chkState:checked + span { display: inline-block; }
  </style>
  <label for="chkState">
    <span class="button">Toggle me!</span>
  </label>
  &nbsp;&nbsp;&nbsp;
  <input type="checkbox" style="display:none" id="chkState" />
  <span>I have been toggled!</span>

Update: You might want to use an anchor instead of a span, as browsers and special software will interpret it as a clickable, but not input control.

Update: You can, in fact, instruct the browser to ignore click events on a button by styling it with pointer-events: none;, however that doesn't stop keyboard events, so one could navigate to the button using keys and press Space or Enter and it wouldn't work. Similarly one could try to add an overlay over the button and it still wouldn't work for the same reason, but that's already besides the point. Anyway, either of these solutions would disable the visual style of the clicked button and web sites usually do not use the default button style anyway.

There is one reason why you should not use this, though, and that is usability. I don't know enough about it, though. In theory, a label should be interpreted the same as the checkbox by software for people with disabilities.

There is this channel I am subscribed to, with various people discussing or demonstrating software development concepts, with various degrees of success. I want to tell you about this series called CSS3 in 30 Days which is very well organized and presented by a clearly talking and articulate developer, Brad Hussey. He's nice, he's Canadian.

And before you go all "I am a software programmer, not a web designer", try watching it for a bit. Personally I am sure I would have solved a lot of what he demos using Javascript. Changing your perspective is a good thing. Note it is about CSS3, which had quite a few improvements over the classical CSS you may know already.

Here is the first "day" of the tutorial:

Paranoia Agent (or Delusion Agent, maybe) is an anime by famous anime director Satoshi Kon, unfortunately killed by cancer in 2010. His work is always more than it seems, focusing on the inner worlds of people and how they all perceive things differently.

The anime is only 13 episodes and starts with a simple case of violent assault on the street and then becomes stranger and stranger until it is not clear which is real and which is in someone's head. It critiques the repressive Japanese society and human nature in general, it goes from police procedural to slapstick comedy, from horror to psychological drama. The ending is, as they say, a mystery that doesn't stay solved for long. I quite liked the anime and I recommend it highly. It is rarer and rarer to find Japanese anime which is not derivative or simply idiotic.

It involves Russia! The story of how Boris Pasternak's Doctor Zhivago got popularized and received the Nobel prize for literature is fascinating and one of the reasons why my wife and I decided to read it as part of our own private book club. She loved the book, although she admitted she didn't understand a lot. I couldn't finish it because I didn't understand it at all!

Let me get this straight, this is not a bad book, the fault lies solely with me. That being said, I've read half of it before I decided to watch the TV adaptation from 2002 and realized I had no idea who anyone was. I had read half of a book, enjoying the way Pasternak describes individual lives, but I didn't remember one character or scene. And the explanation is simple: this is like Crash, on steroids, had sex with Gone With The Wind and had this bastard child around the first World War in Russia. People have three different names, plus nicknames, that the author just splays around without explanation. Events are described through short chapters that sometimes connect via a character seeing the same things from a different perspective or saying something about a character, using a different name than the one we read about it previously. And all these people keep bumping into each other again and again. Sometimes there is no rhythm in how things are written, sometimes it sounds like poetry. There is huge attention to some details and complete ignoring of others. And so on. It is not an easy book; it requires your full attention.

It is obvious that Pasternak loved people and he described their experiences and toils during times of great upheaval, but for him those paled compared with the love stories and the feelings of the characters involved. I can understand how he was confused on why people thought his book was against the Soviet system, where it was clearly about people. I am sure this book is great, it is just not for me. If you want to try it, I suggest you read the summary in Wikipedia so you understand what is going on and you do not read it in bits of 15 minutes in the subway.