"Ron Mexico" <mike.hollo***@mworld.com> wrote in message
news:uWUJBxx3FHA.1416@TK2MSFTNGP09.phx.gbl...
>I have written a graphing engine (very similar to what BigCharts.com
>offers). Basically, it's an ASPX page that accepts parameters and calls
>back-end business objects (dlls) to create a graph.  When the graph is
>created as a jpeg, it is returned to the browser as binary data.  When it
>is used at a low volume, it performs great and returns correctly drawn
>graphs in a timely manner. However when the amount of traffic is increased
>to a high volume, the graphs come back distorted. I've done some research
>on this issue and have found that when .NET creates an object in memory, it
>is not thread safe.  For instance, if an ASPX page gets called several
>times at once and each call creates an object called oGraph, it will create
>several oGraph objects. However, when an instance of the ASPX page goes to
>reference the properties or methods of oGraph, it doesn't care about which
>instance in memory that it uses. It will use one that it didn't create.
>What I end up with is mutated graphs. For example, if two calls were made
>simultaneously to create a 90 day IBM graph and a one day intraday MSFT
>graph, I will end up with a graph with IBM as the title and a plot that
>reflects MSFT intraday data.  Many times it just looks like pieces of one
>graph drawn on top of the other.  Does anyone know of a way to tell the
>ASPX page (and the objects it calls) to 'mind it's own business', so to
>say, and only use the specific instances of objects it initiates? I have
>tried using System.Threading.Monitor.Enter\Exit on all of my objects and
>have also tried the SyncLock blocks, as well. Any help with this would be
>greatly appreciated.
>
>

"Bruce Barker" <brubar_nospamplease_@safeco.com> wrote in message
news:eM6jiYy3FHA.744@TK2MSFTNGP10.phx.gbl...
> you don't say which graphic library you are using. is it thread safe?
> (many aren't). did you use vb module fields? these are not thread safe. by
> default asp.net is thread safe, and object instances are local to the the
> running thread.
>
> -- bruce (sqlwork.com)
>
>
> "Ron Mexico" <mike.hollo***@mworld.com> wrote in message
> news:uWUJBxx3FHA.1416@TK2MSFTNGP09.phx.gbl...
>>I have written a graphing engine (very similar to what BigCharts.com
>>offers). Basically, it's an ASPX page that accepts parameters and calls
>>back-end business objects (dlls) to create a graph.  When the graph is
>>created as a jpeg, it is returned to the browser as binary data.  When it
>>is used at a low volume, it performs great and returns correctly drawn
>>graphs in a timely manner. However when the amount of traffic is increased
>>to a high volume, the graphs come back distorted. I've done some research
>>on this issue and have found that when .NET creates an object in memory,
>>it is not thread safe.  For instance, if an ASPX page gets called several
>>times at once and each call creates an object called oGraph, it will
>>create several oGraph objects. However, when an instance of the ASPX page
>>goes to reference the properties or methods of oGraph, it doesn't care
>>about which instance in memory that it uses. It will use one that it
>>didn't create. What I end up with is mutated graphs. For example, if two
>>calls were made simultaneously to create a 90 day IBM graph and a one day
>>intraday MSFT graph, I will end up with a graph with IBM as the title and
>>a plot that reflects MSFT intraday data.  Many times it just looks like
>>pieces of one graph drawn on top of the other.  Does anyone know of a way
>>to tell the ASPX page (and the objects it calls) to 'mind it's own
>>business', so to say, and only use the specific instances of objects it
>>initiates? I have tried using System.Threading.Monitor.Enter\Exit on all
>>of my objects and have also tried the SyncLock blocks, as well. Any help
>>with this would be greatly appreciated.
>>
>>
>
>

"Ron Mexico" <mike.hollo***@mworld.com> wrote in message
news:u4XLz%23y3FHA.3976@TK2MSFTNGP15.phx.gbl...
> Thank you for the quick reply, Mr. Barker.  I am using the graphics
> library that comes with .NET (GDI+, I guess)  System.Drawing.Graphics and
> System.Drawing.Bitmap are the objects.  If ASP.NET is thread safe by
> default, how else would I be getting combined images?  Here's a more
> descriptive explanation of how the application works:  There are basically
> three 'layers' to my application.
>
> 1.  The ASPX page.  All it does is take the parameters from the querys
> string and create a new instance of the SecurityGraph object (an object I
> wrote) and set some properties (Ticker symbol, plot color, graph
> height/width, frequency, etc).   The SecurityGraph object has a Generate
> method.  The last thing the ASPX page does is call that method.
>
> 2. SecurityGraph.  When the Generate method is called in the SecurityGraph
> object, the database is queried based on the information set in the
> properties of the SecurityGraph object set by the ASPX page which are
> loaded into the new instance of the MWGraph object.
>
> 3.  MWGraph.  This object is where the graph actually gets drawn using the
> Graphics and Bitmap objects.
>
> So if ASP.NET is thread safe, I'm guessing the only thing that can be
> happening to cause the output of several graphs to have shared properties
> is because GDI+ isn't thread safe and the Graphics and Bitmap object are
> being shared when several graphs are being created at once by the same
> aspx-invoked chain of SecurityGraph and MWGraph objects?
>
> As for 'vb module fields', I'm not quite sure what you are referring to.
> Please explain further. Thanks again.
>
>
>
> "Bruce Barker" <brubar_nospamplease_@safeco.com> wrote in message
> news:eM6jiYy3FHA.744@TK2MSFTNGP10.phx.gbl...
>> you don't say which graphic library you are using. is it thread safe?
>> (many aren't). did you use vb module fields? these are not thread safe.
>> by default asp.net is thread safe, and object instances are local to the
>> the running thread.
>>
>> -- bruce (sqlwork.com)
>>
>>
>> "Ron Mexico" <mike.hollo***@mworld.com> wrote in message
>> news:uWUJBxx3FHA.1416@TK2MSFTNGP09.phx.gbl...
>>>I have written a graphing engine (very similar to what BigCharts.com
>>>offers). Basically, it's an ASPX page that accepts parameters and calls
>>>back-end business objects (dlls) to create a graph.  When the graph is
>>>created as a jpeg, it is returned to the browser as binary data.  When it
>>>is used at a low volume, it performs great and returns correctly drawn
>>>graphs in a timely manner. However when the amount of traffic is
>>>increased to a high volume, the graphs come back distorted. I've done
>>>some research on this issue and have found that when .NET creates an
>>>object in memory, it is not thread safe.  For instance, if an ASPX page
>>>gets called several times at once and each call creates an object called
>>>oGraph, it will create several oGraph objects. However, when an instance
>>>of the ASPX page goes to reference the properties or methods of oGraph,
>>>it doesn't care about which instance in memory that it uses. It will use
>>>one that it didn't create. What I end up with is mutated graphs. For
>>>example, if two calls were made simultaneously to create a 90 day IBM
>>>graph and a one day intraday MSFT graph, I will end up with a graph with
>>>IBM as the title and a plot that reflects MSFT intraday data.  Many times
>>>it just looks like pieces of one graph drawn on top of the other.  Does
>>>anyone know of a way to tell the ASPX page (and the objects it calls) to
>>>'mind it's own business', so to say, and only use the specific instances
>>>of objects it initiates? I have tried using
>>>System.Threading.Monitor.Enter\Exit on all of my objects and have also
>>>tried the SyncLock blocks, as well. Any help with this would be greatly
>>>appreciated.
>>>
>>>
>>
>>
>
>

"Ron Mexico" <mike.hollo***@mworld.com> a écrit dans le message de
news:uWUJBxx3FHA.1416@TK2MSFTNGP09.phx.gbl...
> I have written a graphing engine (very similar to what BigCharts.com
> offers). Basically, it's an ASPX page that accepts parameters and calls
> back-end business objects (dlls) to create a graph.  When the graph is
> created as a jpeg, it is returned to the browser as binary data.  When it
is
> used at a low volume, it performs great and returns correctly drawn graphs
> in a timely manner. However when the amount of traffic is increased to a
> high volume, the graphs come back distorted. I've done some research on
this
> issue and have found that when .NET creates an object in memory, it is not
> thread safe.  For instance, if an ASPX page gets called several times at
> once and each call creates an object called oGraph, it will create several
> oGraph objects. However, when an instance of the ASPX page goes to
reference
> the properties or methods of oGraph, it doesn't care about which instance
in
> memory that it uses. It will use one that it didn't create. What I end up
> with is mutated graphs. For example, if two calls were made simultaneously
> to create a 90 day IBM graph and a one day intraday MSFT graph, I will end
> up with a graph with IBM as the title and a plot that reflects MSFT
intraday
> data.  Many times it just looks like pieces of one graph drawn on top of
the
> other.  Does anyone know of a way to tell the ASPX page (and the objects
it
> calls) to 'mind it's own business', so to say, and only use the specific
> instances of objects it initiates? I have tried using
> System.Threading.Monitor.Enter\Exit on all of my objects and have also
tried
> the SyncLock blocks, as well. Any help with this would be greatly
> appreciated.
>
>