IIS Performance - First load of aspx pages - asp.net

I have several projects in asp.net and in all of them I have the same problem. The first time I access an aspx page the load is very slow. Once I close the page and reopen it, the load is very fast. Why is the first load so slow? Can I change any settings in IIS?
Thanks
I have read a lot of documentation but I am not an expert in this and I have not gotten any progress.

By default, asp.net web pages and code files are compiled dynamically when users first request aspx page from a Web site. After pages and code files have been compiled the first time, the compiled resources are cached, so that subsequent requests to the same page are extremely efficient.
More information about asp.net dynamic compilation:
Understanding ASP.NET Dynamic Compilation.
How to: Precompile ASP.NET Web Sites for Deployment.

Ok, so several issues here.
You don't mention if you are talking about your developer computer - say hitting f5 to run the site.
next up, are you deploying a asp.net web site, or a asp.net web site application?
With a application then the compile of the code and pages occurs on YOUR computer, and the .dll's are built by Visual studio (VS). So, at deploy time, then there is a first-time delay, but it not all that long - maybe 5 seconds, and that's as app pool etc. spools up.
However, if you deploy a asp.net web site? Then unlike an "application", the source code (vb, or c#) pages for code behind are included, and deployed to the web site. And this means that IIS does the compile of pages - and often on the fly. This deployment model is often preferred by many, since you can open even the live files on the server, edit one line of code behind, hit save. On next page use, it will re-compile.
If you use an application, then as noted, IIS does not do the code compile, and in fact not even the source code is deployed during a publish. Of course, while there are many benefits to an "application", the ONE big downside is of course that you require a full site re-publish EVEN if you change just one line of code behind.
So, while an application has "some" delay for the first site use, it tends to be considerably less of a delay compared to when using/deploying a web site. (Since then, IIS has to compile the code, and in fact has to compile each page used).
You don't mention/note which deploy model and approach you are using here.
As noted, while the web site option is certainly less efforts to make a change to one page or a bit of code, I still far prefer the "application" approach, since things like "referencing" additional class library and code, and even being able to say use the Rosyln compiler (which may well not be on the server and available to IIS). As a result, I prefer and use an "application" despite the extra efforts required come publish time, but the benefits at developer time far outweigh the downsides.
And of course, one benefit of the "application" approach, is you do as a general rule get far faster web start up times.

Related

ASP.NET - Is it okay to use the source code and link to IIS instead of publish files?

Good day
I moved to another company from a previous one, they task me to modify a existing system with a horrific code, but with patience and dedication, I managed to update the system, but I was shocked that they told me to put the source code on the system and it will be the one that the app in IIS will read. It will read the debug folder of the project. On my previous employer what we do is to publish the file, and that be one to read, but on my current employer,they put the whole source code on the web server.
Is this okay? Or am I right it's a bad practice, well other frameworks put the whole file on the server, so it should be good? Is it?
Thanks and regards
As pointed out, this was a common set.
And after all, why bother to do some whole big publish when you JUST need to modify say a bit of markup in a web page.
So, for those who have the web server "on site", then often they would point VS to the site, and open it directly.
So, to manage/use/work with such a project?
You don't use from vs file->open project, but in fact use file->open web site. At this point, it is assumed you browse directly to the folder that holds the web site - often the live web site.
There are several significant issues to be aware of.
the app in IIS will read. It will read the debug folder of the project.
That is a not a correct assumption, or even correct view. There is no such thing as a "debug" folder. Then again, be it a console app, desktop, or whatever? Sure, when you COMPILE code, it goes to the bin/debug or bin/release folder.
But, you failing to grasp that by using the "web site" option, VS does NOT do the code compile!!! (IIS does!!!). While testing in vs, then vs will do the compile, but if you are modifying the web site directly, then all you have to do is open a web page, and when you hit ctrl-s, you are done - it is now live. And this ALSO applies to code behind.
So, you can open up say the code behind page. Modify one line of code and hit ctrl-s - you are done!!!
So, yes, as you note, a lot of web site(s) were managed this way.
So, the upside is no real deployment is required. And for a larger site, this actually can be a benefit.
However, the downsides are significant, and you VERY much need to be aware of these issues.
First up, careful if you adopt Rosyln extensions. That means your testing/debug/playing/developing code using and allowing VS to compile the code.
however, when you deploy (or edit "live"), then VS is NOT doing the code compile anymore. And this ALSO means then that the web site has both aspx pages, and ALSO the source code pages MUST ALSO exist!!! But often the web site and version of IIS will for example not know about Rosyln extensions etc., so you HAVE to be VERY careful, since it not VS that compiles the code, it is IIS that does this!!
In fact EVEN with a web site application, the "app_code" can and will be compiled by IIS. (I had simple code break when IIS re-compiles that code - it was not aware of say free form text strings that Rosylin allows). So, for a web site application, I actually create my own folder called MyCode and for each code module/class inside, then I right click and choose "compile" for the build options. That way IIS NEVER gets to compile my code!!!).
Now, of course the other option is what we call a "asp.net web application".
In that case, when you publish, then the code is compiled for you, the code behind pages is stripped out, and only the aspx pages remain (and are copied/deployed) to the web site. While this is more "pain" since even a tiny one-line change of code requires a WHOLE web site re-compile and re-deploy.
However, while there is this "increased" pain, there are also significant advantages.
You can have multiple projects in the one project.
you can add and reference other projects assemblies - not have to move/copy the assembles into the bin folder.
So, with better skills, then of course you often build code libraries and systems - systems that ALSO the web site requires. So, a asp.net "web site application" is a far better choice (compared to the "asp.net web site").
So, coming from a traditional software background, then hands down, I prefer the ability to have multiple projects in the one and same web project. And hands down I prefer the runtime compiling and management of external libraries of code and references being managed by the vs as opposed to "hoping" you setup and managed references correctly with a web site.
So, even those starting out say with PHP, or many other systems? Yes, they run a web server all the time, and then go edit the source files - and a simple "save" of the file you just edited means then a browser refresh, and you are done.
however, you lose a lot of control over referenced libraries, and KNOWING the build + compile is the same one you be running on the web site after a publish.
And note that a web site publish in effect will be just the SAME copy of the existing web site and files - there not really a "compile" process for publishing, and hence no "debug" folder really exists. It also means that each page launched on the site can out of the blue cause code to compile.
(Whereas with a asp.net web site application, there is a small startup delay the first time - probably due to JIT's running, but other than that, each additional pages and parts of the web site will not then have significant delays. With a web site re-publish, then huge delays can occur (but then again, often you never really have to re-publish do you - you are editing the live files!!). But, if you are working on a test copy, then yes, you are going to re-publish everything (actually copy the files - since nothing more is required). And as such then the web server really will be slow to start up, and slow to open pages that have not yet triggered compile of the code-behind pages (and you get a gazillion little .dll's as a result).
So, the only real issue here?
MAKE SURE you open the web site using file->open web site as opposed to file->open project. In theory and practice, such "web sites" thus don't have a .sln and project file. (it really is just a folder of files). As noted, many love this setup, especially for larger sites, since then little changes here and there are very easy. However, from an overall software management point of view, using git and source code, and things like writing unit test code, shared libraries, using multiple projects in one vs project file? You give up most of this with the web site option. So, yes, that setup is quick and dirty, but it not all that great if you more formalized in your software development approach.
I prefer strong references, and strong typing during the development process. I also prefer having VS manage my references. So, these abilities are worth more than a simple ctrl-s to update some code. However, if some bug crops up, while it can often be fixed by a simple edit of some code file and ctrl-s, and you are done? it will be harder to track down and find that bug in the first place!!!
To be fair, once a code project is created, then changes and fixes are often rather small - and this again actually favors that simple edit and ctrl-s deployment model.
it can often be painful to have to do a full re-publish of a whole big web application for JUST one little, tiny change of code, or even markup. And in most cases, when I deploy, I stop the web server services, publish, and then re-start the IIS web services.
So, it can "often" be hard to make a case that this deployment model (well, it doesn't really have a deployment model!!!) is bad, since it oh so easy to update bits and parts of an existing running site.
However, in the long run, I really can't endorse this way of development. I MUCH prefer using a web application. It is more git friendly, it allows things like testing code (unit testing), far better use of external class and library code, and you have a MUCH better control of compile and build of your code. Letting IIS compile the code base has increased risk, since you can't be sure during development that your final code and project will run the same when you deploy. (or least be far surer!).
It would be a history lesson.
More than two decades when Microsoft designed ASP.NET 1.0, the developers were using classic ASP which is simply Visual Basic code running on IIS. Thus, ASP.NET 1.0 has the mode of "ASP.NET Web Site" (used by your current employer) that you put source code on IIS and compile on the fly to mimic classic ASP.
It was after a few more years that Microsoft realized how bad that mode is, and introduced "ASP.NET Web Application" mode (used by your previous employer).
Microsoft has urged "ASP.NET Web Site" projects to be migrated to "ASP.NET Web Application" (or simply ASP.NET Core) for more than a decade, but unless IIS stops supporting those projects, many will not migrate at all.
"Is it okay" is impossible to be answered. Your current employer seems to enjoy that very well.
Reference
https://en.wikipedia.org/wiki/ASP.NET_Web_Forms

Application in asp.net slows down when a file is changed

I have a problem with an old application in asp.net.
This application runs on a server with windows server 2012 and is used by hundreds of people at the same time (same app but which is pointed to by different domains).
The problem is this: every time I modify an .asp file, the page takes a lot of time to "recompile" the code and this causes damage to the users who use it.
This problem does not occur with the exact same application but running on another dedicated server used only by one user.
I've been researching for days, the only noteworthy thing found is that, in the server iis, if I recycle on application pool -> select the application, it has exactly the same effect.
I don't know much about windows server so I ask you for help.
Thank you!
You have two types of deployment models.
First is what we call a asp.net web site,
and then second, is what we call a asp.net web site application.
They sound the same - but they are not.
So, while most perfer using a "application"? The ONE down side is that you have to re-publish the WHOLE site if you say change some code behind. This is good, and bad. The good part is that your code is re-compiled BEFORE you publish. (and in fact, you might even want to re-name "app_code", since that does re-compile by the web site.
However, for the most part a web applcation is "harder" to make a small update, since when you publish, you have to re-publish the whole site. But, the good part is that all code tends to be compiled down to ONE .dll. In effect the the site is pre-compiled before publishing. And with a applciaton, then you can add/change and do more things. In effect, the web site "applcation" allows you to do things like create say a custom logon provider. In most cases, this means the WHOLE site is under your developer control. It also means that code behind (source code) is NOT pushed up to the site.
Then you have what is called a asp.net web site. This allows you to say modify the code (code behind) of one page and then push that one page (and code) up to the site. The web site will thus re-compile that one page. You will note the "delay" that you experiance - but it ONLY occures the first time that page is published.
So, for a "application", you will in Visual Studio open up the project (and a sln file) is used.
For a web site, you from Visual Studio go open->web site.
I hands down prefer web applications, but they are MUCH harder to deploy a small change, since as noted, you have to re-publish the whole site.
However, the two different choices would thus explain the "difference" and as to why the other site don't experience the delay as much as you are. However, usually on first load - there can be a one time delay after a re-publish. And this quite much means the site is down for this time to re-publish.
Also, do keep in mind that if you do modify some files (such as web config), then this WILL cause the app-pool to re-start. (and if you not using sql server sessions, but in-memory sessions - they get blown out when you do this).
It also somewhat possible that the server with one user has more memory, more CPU and a much lighter load - so the reduced delay after making changes might well be the light load on that server.
However, the above two different publishing models and types of asp.net sites would be the first thing or at least the first issue to be aware of.
First, you need to determine if it is a website or web application project (https://learn.microsoft.com/en-us/previous-versions/aspnet/dd547590(v=vs.110)?redirectedfrom=MSDN#Anchor_1). Default for web application is rebuild for single page changes while default for website does not force recompilation except if special folders or files are modified. You may check to see if any settings for the app pool differ-- in particular "Disable Overlapping Recycle". You may also check the web.config as there may be a setting that is forcing rebuild. You want also want to look at Explicit Complication/pre-compilation option.
You may want to reference the following resources: https://learn.microsoft.com/en-us/previous-versions/ms178473(v=vs.140)?redirectedfrom=MSDN
https://learn.microsoft.com/en-us/aspnet/web-forms/overview/older-versions-getting-started/deploying-web-site-projects/determining-what-files-need-to-be-deployed-cs
https://learn.microsoft.com/en-us/previous-versions/aspnet/dd547590(v=vs.110)?redirectedfrom=MSDN#Anchor_1
Optimization setting
https://learn.microsoft.com/en-us/archive/blogs/davidebb/a-new-flag-to-optimize-asp-net-compilation-behavior

ASP.NET 'always compiling'. Noob question

I was talking to a guy and he says he likes his site with asp but not asp.net because its 'always compiling'. I Know aspx is compiled and is separate from the main app in a dll. But what does he mean by 'always compiling'? I thought it compiles once on startup and everything you modify aspx file if you modify at all.
But anyways, how is the performance of server side ASP.NET compared to others such as php, python, ruby and java?
You're right, ASP.NET dynamically compiles ASPX web pages and caches the generated binaries when a page is hit after one of the following events:
the IIS application pool has been recycled
a change is made in the bin folder
a change is made in the Web.config file
This dynamic compilation stage comes naturally with a price in terms of page responsiveness. However it affects only the first request coming in to a specific page while it represents an performance enormous benefit for the following requests, since they are served a cached
compiled version of the page.
The performance penalty paid by the first page request can be mitigated by performing the ASP.NET compilation and caching step ahead of time. This technique is known as web site precompilation and is done through a command-line tool included in the .NET Framework called ASP.NET Compilation Tool (Aspnet_compiler.exe).
Related resources:
Understanding ASP.NET Dynamic Compilation
ASP.NET Web Site Precompilation Overview
Very generally....
The "code behind" file is compiled in advance which would generally contain most of "your" code.
The aspx itself it also compiled, but usually not in advance which is probably his reason for saying "always compiling". Each page is compiled as required and the compiled version is cached in temp files until it needs to be compiled again.
'always compiling' of asp.net is possible in some cases - if website have rare requests and application pool's idle time-out(in iis) is very short(1 minute for example). You can note that first request takes long time(about even few seconds), but after first compile it asp.net runs very fast.
speed tests - http://www.wrensoft.com/zoom/benchmarks.html
Since asp (not ASP.NET) is a script language like php everything compiles every time.
In ASP.NET you have to differentiate between presentation items (aspx pages/views) and pure code items (classes/code behind etc).
In general compilation in .NET means compiling code into IL (Intermediate Language or more generally speaking: byte code).
When such a compiled component is actually used it compiles again into actual machine code.
This process is called 'Just In Time' (JIT) compilation.
Presentation
The presentation pages are compiled the first time they are accessed. But your web server notices when they are modified and recompiles them again.
Code
Code items in fact only get compiled once. At the time you hit build in VS.
So what does that mean performance wise? Well think about it, which is further the way from user readable code to machine code or from byte code which is already close to machine code to actual machine code?
I would go with the later any day and in the past for me ASP.NET always has been proven to be faster.
Yes. The absolute first time you access a page it might take longer, but this is not the case you should think about, its the 10th and 20th visitor that you should have in mind.

Difference between 'Web Site' and 'Project' in Visual Studio [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
ASP.NET: Web Site or Web Application?
I have noticed that there is clearly a difference in what you get when you fire up Visual Studio 2008 and choose 'New Project' -> 'ASP.NET Web Application' instead of 'New Web Site' -> 'ASP.NET Web Site'. For example if you choose 'Project', then you can compile to .dll and each page gets a *.aspx.designer.cs codebehind file.
1) Why do we have these two different project types?
2) Which do you prefer?
3) Why would I choose one over the other?
4) What's the deal with the *.aspx.designer.cs files?
They have different purposes.
A website is a site with content that is likely to change over time, that is the pages themselves will change. There is no actual project file and the site is deployed simply as a set of files.
An application is a site where the content is just the application, the dynamic part will mainly be in persistant store such as a database. It will have more complex logic since its likely to represent a set of forms for data entry as much as a means to examine content. It has a project file to more strictly control its configuration and its code deployed as a compiled dll.
1) The 'web site' model was introduced with ASP.NET 2.0, the 'web application' model was the project type of the original .net framework. They both have different uses (see below).
2) It depends on the context. A good example is if you are selling a software product, you may wish to use a 'web application' project because it naturally lends itself to cleanly compiled code.
3) See above, personal preference, maintenance characteristics. An interesting thing that a 'web site' allows you to do that can get you in a lot of trouble is making arbitrary changes to code-behind (typically a *.cs or *.vb) file in notepad while the website is running.
4) The designer.cs file is used to store the auto-generated code. "This code was generated by a tool."
MSDN Article describing the differences
Similar stackoverflow question
I won't duplicate the definition of the 2, since that just got answered.
So why use one over the other?
Web Site lets you treat it like a PHP or classic ASP site, where you can make inline changes that take effect immediately.
Pros
You can make tweaks to the site right on the web server
Deploying is as simple as copying the folder
Cons
If you are not making the changes right on the live site, you can get into change management problems, where you forget to keep all your files in sync
You can get runtime syntax errors displayed to your end users, since the only way to check is to manually run every page
Web Application lets you treat it more like how you would a desktop application - there is one deployable that is compiled on your machine.
Pros
Clear, structured change management. You cannot accidently mix code from two different versions. This can be important when there are 2 people involved - one writing the code, and one responsible for putting files on the server.
Because you compile it on your machine, everything gets syntax checked at that point*
Cons
Deployment is a little more involved then just copying the folder from your development machine. However the usage of the "Publish" command greatly simplifies the process of compiling and putting together what files should be copied to the web server.
Any changes need to be done on your machine, compiled, and a whole new version sent to the web server*
*The aspx/html files are only syntax checked if you turn this on in your build options though. It is also possible to edit these files on the server unless they are compiled into your project.
The simple answers are as follows:
New Web Site - creates code behind pages that are compiled at the server when page is requested.
New Web Project - creates pre-compiled pages into one or more assemblies (entire site even), and deployed on server.
Scenario #1 - If a hacker obtains your code-behind files, any database passwords are exposed. These pages are compiled at the time they are requested. You can choose to pre-compile everything into a large assembly. If not, there is more load on the server.
Scenario #2 - if a hacker obtains your assemblies, they will be obfuscated. Obfuscated assemblies are harder to crack. These assemblies are pre-compiled, thus reducing load on the server.
For more information:
Introduction to Web Application Projects
3) WebApplication projects are buildable by MSBuild. WebSites are not (without a lot of tweaking). If you use TeamSystem with automated builds then this is the way to go.
THe biggest difference that no one has really mentioned (except touched on by Annakata) is that with the model where everything is compiled into a single DLL, your have complete control over the classes that your application generates. You know where they are and can always reference them from anywhere else in the application.
With the single page model, you can't do this. You have to get around it by creating "stub" classes in the AppCode directory, and inheriting those in your pages, but even that isn't ideal, and add complexity.
You'll only really come up agaist this stuff if you're trying to develop an intricate dynamic site, where you dynamically load lots of user-controls at run-time based on content. Then, the differences are painfully clear - hence much of our development stalled on ASP 1.1 until we could go back to the same model later.
Nich
Speaking from experience with both: "Web Sites" are used where there is no testing methodology in place, no CI server, and a culture that encourages and promotes "hotfixes" to specific pages regularly. "Web Applications" are the de facto standard where proper software methodologies are followed and there is unit testing (if not full TDD) and a CI server with a focus on writing clean code and finding bugs before the need for a "hotfix" arises.
Sites are the 2003 original .NET way of doing web dev. In my experience they are extremely problematic since lacking a project definition they can't be reused and have issues with modular coding, have issues with TeamSystem integration and namespacing. The one-to-one bind with a domain and lack of real publishing abstraction creates maintenance problems down the line.
The ancient "classic" ASP way of !codebehind is a serious problem because it again impairs code reuse and testing, and the often cited benefits of allowing hot fixes - if ever called upon - is actually a massive signal that you have a failing development process. The ability to hot fix is of course better than not being able to, but it's something you never want to invoke.
You might say that the problems with the web site model were great enough that MS gave us web apps instead. Personally I would never use them for anything beyond demo code... no actually I wouldn't even do that.
At first there was a Web application project (it behaved similarly to the current Web site project). They changed it to reflect what some users requested. However people wanted the old functionality back so they re-introduced the Web site project which behaves like the original Web application project.
I -- and my workplace -- prefer the Web site project
We like that the files of the website are the files in the file system (no need to add them manually)
No idea
Here's two articles I found about both:
http://damieng.com/blog/2008/02/07/web-site-vs-web-application
http://www.dotnetspider.com/resources/1520-Difference-between-web-site-web-application.aspx
Note: A lot of the issues with Web sites have been resolved with the Web deployment project
Update: Fixed the point 1, Web application was there first
If your work needs to leverage oo language features (class hierarchies, namespaces) or if you need to reuse common code among projects (data access, class libs etc.) then the web application project is the only way to go.
The website project (the clue is in the name) is only really good for non-complex 'brochureware' sites (where the pages consist of static content) as opposed to web applications.
There is very little difference, and I would highly recommend using the Web Site model.
The main difference is for a website, some files need to be placed in certain directories (code files need to be placed in the 'App_Code' directory), besides that, it's pretty straight forward.
If having compiled code for deployment is important to you, and you want a single DLL (opposed to the several that are created when you do a normal publish for a web site), then you'll want to get this add-on: http://msdn.microsoft.com/en-us/asp.net/aa336619.aspx

ASP.NET Performance : web application without precompilation

Currently we're using Web Application project, so we have a gain with compilation. But as far as I know, the aspx pages a still compiled at the first page hit. So does precompilation give a perceptible performance gain ? (first hit exluded).
What type of web site (hits/sec, number of users) will benefit of it ?
Pre-compilation saves the first hit the work of doing the JIT compilation, for a site with a large number of pages who knows how long it will be before every page is visited and gets compilled.
After the first hit there's no difference between the page having compiled JIT or pre-compilled.
We use pre-compilation to ensure that the website will actually compile and don't get caught out by a missing reference or some issue with the production environment. This is also important so that no user has a different experience of our site because they have to wait for the JIT complilation.

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