Custom Http Handler Factory and Possible Concurrency Issues on Application Start

**Juan T. Llibre** · Jun 27 '08, 08:08 PM

Re: Custom Http Handler Factory and Possible Concurrency Issues on Application Start

re:
!what if 100 requests arrive all at once

You mean if 100 requests arrive within the same 10,000th of one second ?
I'd find it very difficult to see that happening.

Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
=============== =============== ========
"Jordan S." <A@B.comwrote in message news:etdJ7JMxIH A.3968@TK2MSFTN GP04.phx.gbl...

Using .NET 3.5...
>
1. Will ASP.NET guarantee that no more than ONE instance of a custom HTTP handler factory (class implementing
IHttpHandlerFac tory) is ever created in an ASP.NET application?
>
2. Assuming the answer to #1 is "yes - never more than one instance" (I hope that's true), then does ASP.NET
automatically take care of concurrency with respect to accessing that one instance?
>
My situation is that I have written a custom handler factory. In it's constructor, I initialize a couple of
class-scoped collections that are subsequently used by logic called by the factory's GetHandler() method.
>
I am concerned that when the app is restarted (for whatever reason), and if the site is really busy, multiple requests
could arrive simultaneously (or close enough to cause concurrency problems) while my custom factory is initializing
itself. Is there anything I can or should do to avoid race conditions or other such concurrency problems - or will
ASP.NET queue the requests until the factory is ready to serve all of the queued requests?
>
I have observed that my custom factory is not instantiated until the first request arrives (after an IIS or
application restart)... thus my concern - what if 100 requests arrive all at once and the factory isn't yet
instantiated and initialized?
>
Thanks.
>
>

**Jordan S.** · Jun 27 '08, 08:08 PM

Re: Custom Http Handler Factory and Possible Concurrency Issues on Application Start

The factory, upon startup (it being instantiated) hits the database. That's
a quick hit, but still it could be a full 1 second for the factory to fully
initialize itself.
It's reasonable to expect multiple requests to arrive within that one
second. Will those requests queue up nicely and wait for the factory to
initialize? Or would multiple instances of the factory be created?

-Jordan

"Juan T. Llibre" <nomailreplies@ nowhere.comwrot e in message
news:e5riLcMxIH A.5520@TK2MSFTN GP06.phx.gbl...

re:
!what if 100 requests arrive all at once
>
You mean if 100 requests arrive within the same 10,000th of one second ?
I'd find it very difficult to see that happening.
>
>
>
Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
=============== =============== ========
"Jordan S." <A@B.comwrote in message
news:etdJ7JMxIH A.3968@TK2MSFTN GP04.phx.gbl...

>Using .NET 3.5...
>>
>1. Will ASP.NET guarantee that no more than ONE instance of a custom HTTP
>handler factory (class implementing IHttpHandlerFac tory) is ever created
>in an ASP.NET application?
>>
>2. Assuming the answer to #1 is "yes - never more than one instance" (I
>hope that's true), then does ASP.NET automatically take care of
>concurrency with respect to accessing that one instance?
>>
>My situation is that I have written a custom handler factory. In it's
>constructor, I initialize a couple of class-scoped collections that are
>subsequently used by logic called by the factory's GetHandler() method.
>>
>I am concerned that when the app is restarted (for whatever reason), and
>if the site is really busy, multiple requests could arrive simultaneously
>(or close enough to cause concurrency problems) while my custom factory
>is initializing itself. Is there anything I can or should do to avoid
>race conditions or other such concurrency problems - or will ASP.NET
>queue the requests until the factory is ready to serve all of the queued
>requests?
>>
>I have observed that my custom factory is not instantiated until the
>first request arrives (after an IIS or application restart)... thus my
>concern - what if 100 requests arrive all at once and the factory isn't
>yet instantiated and initialized?
>>
>Thanks.
>>
>>

>
>
>

**=?Utf-8?B?YnJ1Y2UgYmFya2Vy?=** · Jun 27 '08, 08:08 PM

RE: Custom Http Handler Factory and Possible Concurrency Issues on App

1. no. there is one instance per httpapplication instance. the actually
loading of the code is serialized. httpapplication are keep in pool

-- bruce (sqlwork.com)

"Jordan S." wrote:

Using .NET 3.5...
>
1. Will ASP.NET guarantee that no more than ONE instance of a custom HTTP
handler factory (class implementing IHttpHandlerFac tory) is ever created in
an ASP.NET application?
>
2. Assuming the answer to #1 is "yes - never more than one instance" (I hope
that's true), then does ASP.NET automatically take care of concurrency with
respect to accessing that one instance?
>
My situation is that I have written a custom handler factory. In it's
constructor, I initialize a couple of class-scoped collections that are
subsequently used by logic called by the factory's GetHandler() method.
>
I am concerned that when the app is restarted (for whatever reason), and if
the site is really busy, multiple requests could arrive simultaneously (or
close enough to cause concurrency problems) while my custom factory is
initializing itself. Is there anything I can or should do to avoid race
conditions or other such concurrency problems - or will ASP.NET queue the
requests until the factory is ready to serve all of the queued requests?
>
I have observed that my custom factory is not instantiated until the first
request arrives (after an IIS or application restart)... thus my concern -
what if 100 requests arrive all at once and the factory isn't yet
instantiated and initialized?
>
Thanks.
>
>
>
>

**Juan T. Llibre** · Jun 27 '08, 08:08 PM

Re: Custom Http Handler Factory and Possible Concurrency Issues on Application Start

re:
!It's reasonable to expect multiple requests to arrive within that one second.

Sure, but the requests for code-loading are serialized.

Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
=============== =============== ========
"Jordan S." <A@B.comwrote in message news:e5UrlgMxIH A.6096@TK2MSFTN GP06.phx.gbl...

The factory, upon startup (it being instantiated) hits the database. That's a quick hit, but still it could be a full
1 second for the factory to fully initialize itself.
It's reasonable to expect multiple requests to arrive within that one second. Will those requests queue up nicely and
wait for the factory to initialize? Or would multiple instances of the factory be created?
>
-Jordan
>
>
"Juan T. Llibre" <nomailreplies@ nowhere.comwrot e in message news:e5riLcMxIH A.5520@TK2MSFTN GP06.phx.gbl...

>re:
>!what if 100 requests arrive all at once
>>
>You mean if 100 requests arrive within the same 10,000th of one second ?
>I'd find it very difficult to see that happening.
>>
>>
>>
>Juan T. Llibre, asp.net MVP
>asp.net faq : http://asp.net.do/faq/
>foros de asp.net, en español : http://asp.net.do/foros/
>============== =============== =========
>"Jordan S." <A@B.comwrote in message news:etdJ7JMxIH A.3968@TK2MSFTN GP04.phx.gbl...

>>Using .NET 3.5...
>>>
>>1. Will ASP.NET guarantee that no more than ONE instance of a custom HTTP handler factory (class implementing
>>IHttpHandlerF actory) is ever created in an ASP.NET application?
>>>
>>2. Assuming the answer to #1 is "yes - never more than one instance" (I hope that's true), then does ASP.NET
>>automatical ly take care of concurrency with respect to accessing that one instance?
>>>
>>My situation is that I have written a custom handler factory. In it's constructor, I initialize a couple of
>>class-scoped collections that are subsequently used by logic called by the factory's GetHandler() method.
>>>
>>I am concerned that when the app is restarted (for whatever reason), and if the site is really busy, multiple
>>requests could arrive simultaneously (or close enough to cause concurrency problems) while my custom factory is
>>initializin g itself. Is there anything I can or should do to avoid race conditions or other such concurrency
>>problems - or will ASP.NET queue the requests until the factory is ready to serve all of the queued requests?
>>>
>>I have observed that my custom factory is not instantiated until the first request arrives (after an IIS or
>>application restart)... thus my concern - what if 100 requests arrive all at once and the factory isn't yet
>>instantiate d and initialized?
>>>
>>Thanks.
>>>
>>>

>>
>>
>>

>
>
>

**Jordan S.** · Jun 27 '08, 08:08 PM

Re: Custom Http Handler Factory and Possible Concurrency Issues on Application Start

Thanks Juan.

"Juan T. Llibre" <nomailreplies@ nowhere.comwrot e in message
news:eXcST9MxIH A.5288@TK2MSFTN GP06.phx.gbl...

re:
!It's reasonable to expect multiple requests to arrive within that one
second.
>
Sure, but the requests for code-loading are serialized.
>
>
>
Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
=============== =============== ========
"Jordan S." <A@B.comwrote in message
news:e5UrlgMxIH A.6096@TK2MSFTN GP06.phx.gbl...

>The factory, upon startup (it being instantiated) hits the database.
>That's a quick hit, but still it could be a full 1 second for the factory
>to fully initialize itself.
>It's reasonable to expect multiple requests to arrive within that one
>second. Will those requests queue up nicely and wait for the factory to
>initialize? Or would multiple instances of the factory be created?
>>
>-Jordan
>>
>>
>"Juan T. Llibre" <nomailreplies@ nowhere.comwrot e in message
>news:e5riLcMxI HA.5520@TK2MSFT NGP06.phx.gbl.. .

>>re:
>>!what if 100 requests arrive all at once
>>>
>>You mean if 100 requests arrive within the same 10,000th of one second ?
>>I'd find it very difficult to see that happening.
>>>
>>>
>>>
>>Juan T. Llibre, asp.net MVP
>>asp.net faq : http://asp.net.do/faq/
>>foros de asp.net, en español : http://asp.net.do/foros/
>>============= =============== ==========
>>"Jordan S." <A@B.comwrote in message
>>news:etdJ7JMx IHA.3968@TK2MSF TNGP04.phx.gbl. ..
>>>Using .NET 3.5...
>>>>
>>>1. Will ASP.NET guarantee that no more than ONE instance of a custom
>>>HTTP handler factory (class implementing IHttpHandlerFac tory) is ever
>>>created in an ASP.NET application?
>>>>
>>>2. Assuming the answer to #1 is "yes - never more than one instance" (I
>>>hope that's true), then does ASP.NET automatically take care of
>>>concurrenc y with respect to accessing that one instance?
>>>>
>>>My situation is that I have written a custom handler factory. In it's
>>>constructo r, I initialize a couple of class-scoped collections that are
>>>subsequent ly used by logic called by the factory's GetHandler() method.
>>>>
>>>I am concerned that when the app is restarted (for whatever reason),
>>>and if the site is really busy, multiple requests could arrive
>>>simultaneous ly (or close enough to cause concurrency problems) while my
>>>custom factory is initializing itself. Is there anything I can or
>>>should do to avoid race conditions or other such concurrency problems -
>>>or will ASP.NET queue the requests until the factory is ready to serve
>>>all of the queued requests?
>>>>
>>>I have observed that my custom factory is not instantiated until the
>>>first request arrives (after an IIS or application restart)... thus my
>>>concern - what if 100 requests arrive all at once and the factory isn't
>>>yet instantiated and initialized?
>>>>
>>>Thanks.
>>>>
>>>>
>>>
>>>
>>>

>>
>>
>>

>
>
>

**Jordan S.** · Jun 27 '08, 08:08 PM

Re: Custom Http Handler Factory and Possible Concurrency Issues on App

Thanks Bruce.

"bruce barker" <brucebarker@di scussions.micro soft.comwrote in message
news:2E899BBE-4751-4BD3-B8A8-ED86BDA8C240@mi crosoft.com...

1. no. there is one instance per httpapplication instance. the actually
loading of the code is serialized. httpapplication are keep in pool
>
-- bruce (sqlwork.com)
>
>
"Jordan S." wrote:
>

>Using .NET 3.5...
>>
>1. Will ASP.NET guarantee that no more than ONE instance of a custom HTTP
>handler factory (class implementing IHttpHandlerFac tory) is ever created
>in
>an ASP.NET application?
>>
>2. Assuming the answer to #1 is "yes - never more than one instance" (I
>hope
>that's true), then does ASP.NET automatically take care of concurrency
>with
>respect to accessing that one instance?
>>
>My situation is that I have written a custom handler factory. In it's
>constructor, I initialize a couple of class-scoped collections that are
>subsequently used by logic called by the factory's GetHandler() method.
>>
>I am concerned that when the app is restarted (for whatever reason), and
>if
>the site is really busy, multiple requests could arrive simultaneously
>(or
>close enough to cause concurrency problems) while my custom factory is
>initializing itself. Is there anything I can or should do to avoid race
>conditions or other such concurrency problems - or will ASP.NET queue the
>requests until the factory is ready to serve all of the queued requests?
>>
>I have observed that my custom factory is not instantiated until the
>first
>request arrives (after an IIS or application restart)... thus my
>concern -
>what if 100 requests arrive all at once and the factory isn't yet
>instantiated and initialized?
>>
>Thanks.
>>
>>
>>
>>

>

Custom Http Handler Factory and Possible Concurrency Issues on Application Start

Custom Http Handler Factory and Possible Concurrency Issues on Application Start

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