ASP.NET, threading and static member.

[Francois]

Hi all,

Each time an HTTP request is received by IIS, it forwards it to the ASP.NET
worker process. Then does the ASP.NET worker process in turn start a new
thread for each HTTP request it serves (from a pool of thread for example).
Or are all HTTP requests served by the same thread?

An other question is related to static members. A static member in a class
will have the same value across all its instance. But for example if 2
instances of the class are in 2 different threads, will the static member
still share the value or not? If I remember well, in Java, static member do
not share the same value between different threads and I would like to know
if it is the same thing in C# or not.

If anyone got a good link explaining one of both of the 2 topics above that
would be great too !

Thanks in advance,

Francois

 

[Jon Skeet [C# MVP]]

Each time an HTTP request is received by IIS, it forwards it to the ASP.NET
worker process. Then does the ASP.NET worker process in turn start a new
thread for each HTTP request it serves (from a pool of thread for example).
Or are all HTTP requests served by the same thread?

I believe they're served by the thread-pool.

An other question is related to static members. A static member in a class
will have the same value across all its instance.

It's not that it's shared across all instances - it's that the member
belongs to the type rather than to any instance.

But for example if 2
instances of the class are in 2 different threads, will the static member
still share the value or not? If I remember well, in Java, static member do
not share the same value between different threads and I would like to know
if it is the same thing in C# or not.

It's the same in C# as in Java, but you remember Java incorrectly.
Static members are shared across threads.

 

[Francois]

Tx a lot Jon,

Do you know if there is there any way to set some sort of a type value that
will be limited to the scope of a thread only? or is that impossible to do?

Tx in advance and tx again for your answer.

Francois

 

[Guest]

You can keep thread specific data by using SetData and GetData static
methods. to give the appearance that it's part of the type, you can use a
property to wrap that logic.

Tx a lot Jon,

Do you know if there is there any way to set some sort of a type value that
will be limited to the scope of a thread only? or is that impossible to do?

Tx in advance and tx again for your answer.

Francois

 

[Scott Allen]

Hi Francois:

I'm not sure what you ultimately want to accomplish, but in ASP.NET
you generally want a value around that is tied to a specific request,
not a specific thread. To do this you can use the Context.Items
collection.

--
Scott
http://www.OdeToCode.com/blogs/scott/

Tx a lot Jon,

Do you know if there is there any way to set some sort of a type value that
will be limited to the scope of a thread only? or is that impossible to do?

Tx in advance and tx again for your answer.

Francois

 

[Jon Skeet [C# MVP]]

You can keep thread specific data by using SetData and GetData static
methods. to give the appearance that it's part of the type, you can use a
property to wrap that logic.

Alternatively, use the [ThreadStatic] attribute
(ThreadStaticAttribute). It's only available on static variables
(AFAICT), but it keeps one variable per thread.

 

[Guest]

Learning something new every day, thanks Jon!

You can keep thread specific data by using SetData and GetData static
methods. to give the appearance that it's part of the type, you can use a
property to wrap that logic.

Alternatively, use the [ThreadStatic] attribute
(ThreadStaticAttribute). It's only available on static variables
(AFAICT), but it keeps one variable per thread.

 

[bruce barker]

asp.net not only uses a thread pool, but may switch threads during request
processing (thread agile). this makes thread local storage unreliable.

in .net, static data is shared across all thread (unless the ThreadStatic
attribute is used, which then uses TLS). due to aps.net thread agility
mentioned above, you can not use this method.

-- bruce (sqlwork.com)



| Hi all,
|
| Each time an HTTP request is received by IIS, it forwards it to the
ASP.NET
| worker process. Then does the ASP.NET worker process in turn start a new
| thread for each HTTP request it serves (from a pool of thread for
example).
| Or are all HTTP requests served by the same thread?
|
| An other question is related to static members. A static member in a class
| will have the same value across all its instance. But for example if 2
| instances of the class are in 2 different threads, will the static member
| still share the value or not? If I remember well, in Java, static member
do
| not share the same value between different threads and I would like to
know
| if it is the same thing in C# or not.
|
| If anyone got a good link explaining one of both of the 2 topics above
that
| would be great too !
|
| Thanks in advance,
|
| Francois
|
|

 

[Francois]

Thanks to all for all your information.

Best regards,

Francois.