Is access to the Session thread-safe?

When accessing, for example, an object stored in the session such as:

Session[ "MyObject" ].MyProperty = "Some Value";

Is access to MyObject thread-safe?

Chris Newby

Hi Chris:

Here are some details:

ASP.NET does manage access to session state with a ReaderWriterLock.
The default is to take a writer lock, which serializes requests coming
in on the same session (using EnableSessionState="ReadOnly" takes a
reader lock and does allow concurrent request processing on a
session).

In this example, you are not really modifying session state, but
modifying an object through a reference stored in session state. If
anyone else has a reference to the same object the code is only thread
safe if MyObject is thread safe.

Know what I mean?

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


On Sun, 27 Mar 2005 19:59:26 -0500, "Chris Newby"
<> wrote:

> When accessing, for example, an object stored in the session such as:
>
>Session[ "MyObject" ].MyProperty = "Some Value";
>
>Is access to MyObject thread-safe?
>

Yeah, makes perfect sense.

Could you possibly elaborate a little more on exactly when ASP.NET creates
and releases the ReaderWriter Lock?


"Scott Allen" <> wrote in message
news...
> Hi Chris:
>
> Here are some details:
>
> ASP.NET does manage access to session state with a ReaderWriterLock.
> The default is to take a writer lock, which serializes requests coming
> in on the same session (using EnableSessionState="ReadOnly" takes a
> reader lock and does allow concurrent request processing on a
> session).
>
> In this example, you are not really modifying session state, but
> modifying an object through a reference stored in session state. If
> anyone else has a reference to the same object the code is only thread
> safe if MyObject is thread safe.
>
> Know what I mean?
>
> --
> Scott
> http://www.OdeToCode.com/blogs/scott/
>
>
> On Sun, 27 Mar 2005 19:59:26 -0500, "Chris Newby"
> <> wrote:
>
> > When accessing, for example, an object stored in the session such as:
> >
> >Session[ "MyObject" ].MyProperty = "Some Value";
> >
> >Is access to MyObject thread-safe?
> >
>

When the SessionStateModule catches the AcquireRequestState event
during request processing. This happens before control reaches the
ASPX page handler.

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

On Sun, 27 Mar 2005 21:15:12 -0500, "Chris Newby"
<> wrote:

>Yeah, makes perfect sense.
>
>Could you possibly elaborate a little more on exactly when ASP.NET creates
>and releases the ReaderWriter Lock?
>
>

Thanks Scott, very helpful//

"Scott Allen" <> wrote in message
news:...
> When the SessionStateModule catches the AcquireRequestState event
> during request processing. This happens before control reaches the
> ASPX page handler.
>
> --
> Scott
> http://www.OdeToCode.com/blogs/scott/
>
> On Sun, 27 Mar 2005 21:15:12 -0500, "Chris Newby"
> <> wrote:
>
> >Yeah, makes perfect sense.
> >
> >Could you possibly elaborate a little more on exactly when ASP.NET
creates
> >and releases the ReaderWriter Lock?
> >
> >
>