I am caching some data in VB.NET using System.Web.Cach ing, is it possible to
lock the cache so that other sessions attempting to access the same cache
wait when it is being updated? I have the cache using a sliding timeout and
a dependency on the text file its data is extracted from.
If it's relevant, based on current statistics, I do not expect more than
about 400 people to be accessing the web site at the same time.
I've seen it appears easy in C# but I couldn't find anything regarding VB.
Andrew
13  2344 
Andrew,
You make me curious, why would you do that? Seems to me a strange solution,
because you should than make a mechanisme for those other 399 who try to
access that cache in my idea. When it is, than what it the action on that
catch?
I am real curious about this how you did that.
Cor
Cor Ligthert wrote: Andrew,
You make me curious, why would you do that? Seems to me a strange
solution, because you should than make a mechanisme for those other
399 who try to access that cache in my idea. When it is, than what it
the action on that catch?
I am real curious about this how you did that.
Cor
The cached data is a lookup table which has the same data for every user.
The cache applies to the web application rather than per-session. Unless I
have misunderstood the docs.
Andrew
Andrew,
Clear,
Is it than not something as updating the tables, create a page to kill the
cache and let it go again, where I assume that the cache is created when it
is nothing?
I never used that cache, however that is from what I understand from it,
would probably as first try to do it.
Cor
> Is it than not something as updating the tables, create a page to kill the cache and let it go again, where I assume that the cache is
created when it is nothing?
Imagine this scenario:-
--------------------------
session1 starts and finds the cache is nothing and starts parsing the data
to create the cache
While session1 is parsing the data, session2 starts and finds the cache is
nothing, so it starts parsing the data to create the cache
session1 finishes parsing the data and creates the cache
session2 finishes parsing the data and creates the cache, except session1 is
still writing the cache so something goes wrong
--------------------------
Preferred scenario:-
session1 starts and finds the cache is nothing, locks the cache and starts
parsing the data to create the cache
While session1 is parsing the data, session2 starts and finds the cache is
locked, so it waits until the cache is unlocked.
Andrew
The MSDN docs say Cache is thread safe.
"Andrew Morton" <ak*@in-press.co.uk.inv alid> wrote in message
news:eu******** ******@TK2MSFTN GP15.phx.gbl... I am caching some data in VB.NET using System.Web.Cach ing, is it possible
to lock the cache so that other sessions attempting to access the same cache
wait when it is being updated? I have the cache using a sliding timeout
and a dependency on the text file its data is extracted from.
If it's relevant, based on current statistics, I do not expect more than
about 400 people to be accessing the web site at the same time.
I've seen it appears easy in C# but I couldn't find anything regarding VB.
Andrew
Andrew,
Did you test this and did it work as you describe. For me is the problem
that somebody once wrote here that an aspnet dll is running itself
automaticly on more threads for sessions.
When that is not true, than in my opinion can the effect not be as you
write.
However I never saw any documentation which tells something about the proces
of a webapplication dll.
Sorry
Cor
JD wrote: The MSDN docs say Cache is thread safe.
How do I use that to make other threads pause when one thread is updating
the cache?
However, looking through the docs about thread safety lead me to SyncLock,
which I think is what I want.
Andrew
The Cache automatically synchronizes access to the data. I believe it uses a
multireader, single writer lock. In other words you don't have to do
anything.
"Andrew Morton" <ak*@in-press.co.uk.inv alid> wrote in message
news:uC******** ******@TK2MSFTN GP10.phx.gbl... JD wrote: The MSDN docs say Cache is thread safe.
How do I use that to make other threads pause when one thread is updating
the cache?
However, looking through the docs about thread safety lead me to SyncLock,
which I think is what I want.
Andrew
But let me emphasize, the block of code that does -> {check if the cache
data is Nothing and if it is Nothing do the update to cache } must be
synchonized.
"JD" <an**@anon.anon > wrote in message
news:uQ******** ******@TK2MSFTN GP10.phx.gbl... The Cache automatically synchronizes access to the data. I believe it uses
a multireader, single writer lock. In other words you don't have to do
anything.
"Andrew Morton" <ak*@in-press.co.uk.inv alid> wrote in message
news:uC******** ******@TK2MSFTN GP10.phx.gbl... JD wrote: The MSDN docs say Cache is thread safe.
How do I use that to make other threads pause when one thread is
updating the cache?
However, looking through the docs about thread safety lead me to
SyncLock, which I think is what I want.
Andrew
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