Bending Google to your will

A new variation on the famous "French Military Victories": look who's top of the list for "fuckwit"...

Tips for Distributed Applications

Ingo Rammer gave an excellent presentation on Optimising Distributed Applications at DNUG yesterday. I'm going to apply all my limited skills at précis to summarise it here, so that it won't matter when I lose the scrappy bit of paper that I took notes on. The following may be incomprehensible if you weren't at the talk.

Preliminaries: Don't write distributed apps unless you have to! Seriously, modern databases can easily cope with 100s of concurrent connections; your desktop app may well just be able to connect straight to the database without a middle tier. This will cut out loads of complexity. It's practically heresy to suggest "optimising" 3-tier apps by deleting a tier, but you see his point.

Main Idea: Profile things in the following order: Network, Database Access, Memory Usage, In-Process Stuff. No point spending hours bit-twiddling if the real problem is that your app is thrashing the daylights out of the network.

1. Network Profiling. Get hold of Ethereal, TcpTrace and ProxyTrace, and use them. If trying to insert TcpTrace into a remoting conversation, tweak the server config file by pointing the machinename attribute of the channel element at TcpTrace.
   
   
2. Database Access. Sql Profiler is your friend. DataSets are, if not evil, then certainly to be avoided for high-volume transactional stuff. (For instance: copying a bunch of rows will produce many INSERT statements if you use a DataSet, but can be done with a single INSERT INTO ... SELECT FROM if you write the t-sql yourself.) Except in SQL Server 2005, where we have snapshot isolation, a SELECT statement will take out a shared lock -- although you can add WITH (NOLOCK) if you don't mind seeing uncommitted changes. This fact alone should make you think twice about using Identity Tables (imagine what happens when that lock escalates!); use Identity columns instead, it's what they're for. Lastly, locks in Enterprise Services will last longer than in regular ADO.NET, because the isolation level defaults to Serializable instead of Read Committed; if you don't need this, then change it.
   
   
3. Memory Allocation. Use CLR Profiler to find out what is allocating memory in your app. Remember to profile a release build! The goal is to allocate as little as possible (especially in ASP.NET, where allocating great wads of memory is likely to prompt a process recycle) and to avoid getting temporary objects into generation 2 of the GC. Again, DataSets seem to be much bigger than their alternatives.
   
   
4. Everything else. Now you can throw Compuware DevPartner, or RedGate ANTS, or Automated QA AQTime at the problem. You may need to try all three.
   

Tips:

• Look at Network Load Balancing. It's built in to Server 2003; you can just point at a bunch of other (not necessarily 2003) machines and say "make them a load-balancing cluster". No hardware or software requirements, but obviously you have to design with this architecture in mind, because of state-management and caching issues.
  
• The communication between Web Server and Web Services, if they are on different machines, will be limited by default to 2 concurrent connections (because the HTTP spec says so). You will probably want to fix this, which you can do on the web server by inserting something like
  

  <configuration>
     <system.net>
        <connectionManagement>
           <add name = "*" maxconnection = "99" />
        </connectionManagement>
     </system.net>
  </configuration>

  
  
• If you're using Integrated Windows authentication for your Web Service, every WS call will be rejected at first until a challenge-response is completed. This means your first call, with all its data, is pretty much a waste of time. Obvious ways around this include: having a "ping" method you call first, caching the proxy class, or calling PreAuthenticate. None of these will work (PreAuthenticate is good for Basic auth, though). Solution is either go for Basic over SSL -- not nearly as bad as it sounds, because once you have an authenticated connection you can just use it without further faffing around -- or, if you can, use the proxy's UnsafeAuthenticatedConnectionSharing property, and remember to also set the ConnectionGroupName so you're not sharing that connection with just anybody.
  

Lastly, a few random things: Use ZoomIn for demos when you can't increase the font size of a tool you want to demo. Use Notepad2 as a replacement for notepad; it does syntax highlighting and all sorts of good stuff. And subscribe to Ingo's Very Infrequent Newsletter on distributed app design.

What .NET Developers Should Know

Interesting article full of interview questions.

Uh-oh

This is what I get for reading other people's blogs:

Caution! Stressed Penguins!

Do not harass the penguins.

More Firefox tips

Scot's newsletter.

Oddest headline of the year so far...

"Underwater Gnome Threat Returns" (what would we do without the b3ta.com newsletter?)

Devious boxing example

How not to use boxing in .net...

VS Powertoys

Editor Zoom.

Core Powertoys.

Powertoys Weblog.

Running Civ on VPC

Tips available here.

Evaluating expressions at the command prompt

CMD.EXE can do more than you think.

Geek Love

A little early for Valentine's Day, but this touched my heart...

Disk Compaction in VPC

Script available here.

Test Your VBScript Intuition

Will you answer all the questions correctly? Would you want to?

Gay Penguin Update

Here.

Indigo

An introduction to Indigo, from the Longhorn Developer Centre.

Debugging the debugger

The most complete collection of fixes for debugger problems in VS7 that I've ever seen...

Unicode Frenzy!

Two Very Large Fonts: Code2000 and Code2001.

Enable support for surrogates in 2000/XP as follows:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\LanguagePack]
SURROGATE=(REG_DWORD)0x00000002

[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\Scripts\42]
IEFixedFontName=Code2001
IEPropFontName=Code2001

(optionally)
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT CurrentVersionLanguagePack\SurrogateFallback]
Plane1=[Plane 1 Font Face name]
Plane2=[Plane 2 Font Face name] ...

(as explained here and here)

View your sparkly new fonts using BabelMap or True Type Explorer (both free, both lovely).

The ultimate authority is Unicode.org, and my sudden interest in the subject is all down to this blog.

We Are Zogg

A Child's Primer.

Prettifying SPS/WSS

A guide to the startlingly bletcherous process of customising sharepoint.

Speeding up Firefox the right way

Tips here.

SharePoint Stuff

SmartPart allows ascx user controls to become web parts with minimal fuss.

Web Part Toolkit has a bunch of useful admin tools, including SCA and InstallAssemblies.


SharePoint Explorer and SharePoint User Manager.

Biztalk Power Toys

Useful BizTalk gizmos.

MS Enterprise Library

This looks like a useful collection of application blocks. Can't quite tell at the minute, since you have to register and the server seems to be down.

More info in this blog.

Speed up VPC Disk I/O

(if you're lucky)

http://blogs.msdn.com/Virtual_PC_Guy/archive/2005/02/01/364383.aspx