C# – WebResource.axd and ScriptResource.axd load very slowly

asp.netciisscriptmanager

Under normal circumstances the two .axd files load at normal speeds to the browser, i.e. a few hundred milliseconds. I can see them load normally along with all the other page elements by looking at the waterfall chart (network chart) in chrome or another debugging tool.

Occasionally some kind of issue occurs where the two files take about a minute to load. Here are a few other notes:

All other elements on the page load at normal speeds.
It generally occurs once or twice a day and lasts for a few minutes.
I can see Requests Queued spike on performance counters at the same time.
CPU, memory and disk all stay normal during this time.
Had one outage of a few hours today that required an application restart to resolve.
Not combining the .axd files or anyhing like that yet.
Have URL rewriting implemented site-wide. axd files are excluded from rewriting.
App built for C# 3.5
IIS 7
I’m using the CDN version of ScriptManager, eg:

<asp:scriptreference name="MicrosoftAjax.js" path="http://ajax.microsoft.com/ajax/3.5/MicrosoftAjax.js"></asp:scriptreference>

It looks like others have had a similar issue, but not solved:

WebResource.axd and ScriptResource.axd weird behaviour

WebResource.axd & ScriptResource.axd loading takes more than 1 minute

Question:

Any idea how to figure out what is causing these two files to load so slowly occasionally?

Also, are there any workarounds, such as prebuilding the .axd files or something..?

Best Answer

Maybe hosting http://ajax.microsoft.com/ajax/3.5/MicrosoftAjax.js locally would help?

This is the style that Microsoft tends to use in their examples.

It appears that the guidance in this area may have changed, as StyleCop now enforces the use of the C# specific aliases.

C# – the difference between const and readonly in C#

Apart from the apparent difference of

having to declare the value at the time of a definition for a const VS readonly values can be computed dynamically but need to be assigned before the constructor exits.. after that it is frozen.
const's are implicitly static. You use a ClassName.ConstantName notation to access them.

There is a subtle difference. Consider a class defined in AssemblyA.

public class Const_V_Readonly
{
  public const int I_CONST_VALUE = 2;
  public readonly int I_RO_VALUE;
  public Const_V_Readonly()
  {
     I_RO_VALUE = 3;
  }
}

AssemblyB references AssemblyA and uses these values in code. When this is compiled:

in the case of the const value, it is like a find-replace. The value 2 is 'baked into' the AssemblyB's IL. This means that if tomorrow I update I_CONST_VALUE to 20, AssemblyB would still have 2 till I recompile it.
in the case of the readonly value, it is like a ref to a memory location. The value is not baked into AssemblyB's IL. This means that if the memory location is updated, AssemblyB gets the new value without recompilation. So if I_RO_VALUE is updated to 30, you only need to build AssemblyA and all clients do not need to be recompiled.

So if you are confident that the value of the constant won't change, use a const.

public const int CM_IN_A_METER = 100;

But if you have a constant that may change (e.g. w.r.t. precision).. or when in doubt, use a readonly.

public readonly float PI = 3.14;

Update: Aku needs to get a mention because he pointed this out first. Also I need to plug where I learned this: Effective C# - Bill Wagner

Best Answer

Related Solutions

C# – the difference between String and string in C#

This is the style that Microsoft tends to use in their examples.

C# – the difference between const and readonly in C#

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