Best Practices to Improve ASP.net Web Application Performance

8/6/2019 Best Practices to Improve ASP.net Web Application Performance

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Since ASP.NET manages session state by default, you pay the cost in memory

even if you don't use it, i.e., whether you store your data in-process or on

state server or in a SQL database, session state requires memory and it's also

time consuming when you store or retrieve data from it.

Solution

You may not require session state when your pages are static or when you

do not need to store information captured in the page.

In such cases where you need not use session state, disable it on your web

form using the directive:

<@%Page EnableSessionState="false"%>

In case you use the session state only to retrieve data from it and not toupdate it, make the session state read only by using the directive:

<@%Page EnableSessionState ="ReadOnly"%>

3. Disable View State of a Page if possible

View state is a fancy name for ASP.NET storing some state data in a hidden

input field inside the generated page. When the page is posted back to the

server, the server can parse, validate, and apply this view state data back to

the page's tree of controls.

View state is a very powerful capability since it allows state to be persisted

with the client and it requires no cookies or server memory to save this state.

Many ASP.NET server controls use view state to persist settings made during

interactions with elements on the page, for example, saving the current page

that is being displayed when paging through data.

How it affects performance

1. There are a number of drawbacks to the use of view state, however.

2. It increases the total payload of the page both when served and whenrequested. There is also an additional overhead incurred when

serializing or deserializing view state data that is posted back to the

server.

3. View state increases the memory allocations on the server. Several

server controls, the most well known of which is the DataGrid, tend

to make excessive use of view state, even in cases where it is not

needed.

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Solution

Pages that do not have any server postback events can have the view state

turned off.

The default behavior of the ViewState property is enabled, but if you don'tneed it, you can turn it off at the control or page level. Within a control,

simply set theEnableViewState property to false, or set it globally within

the page using this setting:

<%@ Page EnableViewState="false" %>

If you turn view state off for a page or control, make sure you thoroughly test

your pages to verify that they continue to function correctly.

4. Set debug=false in web.config

When you create the application, by default this attribute is set to "true"

which is very useful while developing. However, when you are deploying your

application, always set it to "false".


Setting it to "true" requires the PDB information to be inserted into the file

and this results in a comparatively larger file and hence processing will be

slow.

Solution

Therefore, always set debug="false" before deployment.

5. Avoid Response.Redirect

Response.Redirect() method simply tells the browser to visit another

page.


Redirects are also very chatty. They should only be used when you are

transferring people to another physical web server.

Solution

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For any transfers within your server, use .transfer! You will save a lot of

needless HTTP requests. Instead of telling the browser to redirect, it simply

changes the "focus" on the Web server and transfers the request. This means

you don't get quite as many HTTP requests coming through, which therefore

eases the pressure on your Web server and makes your applications run

faster.

Tradeoffs

1. ".transfer" process can work on only those sites running on the

server. Only Response.Redirect can do that.

2. Server.Transfer maintains the original URL in the browser. This

can really help streamline data entry techniques, although it may

make for confusion when debugging

5. A) To reduce CLR Exceptions count, use Response.Redirect

(".aspx", false) instead of response.redirect (".aspx").

6. Use the String builder to concatenate string


String is Evil when you want to append and concatenate text to

your string. All the activities you do to the string are stored in the

memory as separate references and it must be avoided as much as possible.

i.e. When a string is modified, the run time will create a new string andreturn it, leaving the original to be garbage collected. Most of the time, this is

a fast and simple way to do it, but when a string is being modified

repeatedly, it begins to be a burden on performance: all of those allocations

eventually get expensive.

Solution

Use String Builder whenever string concatenation is needed so that it only

stores the value in the original string and no additional reference is

created.

7. Avoid throwing exceptions


Exceptions are probably one of the heaviest resource hogs and causes of

slowdowns you will ever see in web applications, as well as windows

applications.

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Solution

You can use as many try /catch blocks as you want. Using exceptions

gratuitously is where you lose performance. For example, you should stay

away from things like using exceptions for control flow.

8. Use Finally Method to kill resources

1. The finally method gets executed independent of the outcome of

the Block.

2. Always use the finally block to kill resources like closing database

connection, closing files and other resources such that they get

executed independent of whether the code worked in Try or went

to Catch.

9. Use Client Side Scripts for validations

User Input is Evil and it must be thoroughly validated before processing to

avoid overhead and possible injections to your applications.

How It improves performance

Client site validation can help reduce round trips that are required to process

user's request. In ASP.NET, you can also use client side controls to validate

user input. However, do a check at the Server side too to avoid the infamous

JavaScript disabled scenarios.

10. Avoid unnecessary round trips to the server


Round trips significantly affect performance. They are subject to network

latency and to downstream server latency. Many data-driven Web sites

heavily access the database for every user request. While connection pooling

helps, the increased network traffic and processing load on the database

server can adversely affect performance.

Solution

1. Keep round trips to an absolute minimum

2. Implement Ajax UI whenever possible. The idea is to avoid full page

refresh and only update the portion of the page that needs to be

changed

11. Use Page.ISPostBack

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Make sure you don't execute code needlessly.

Use Page.ISPostBack property to ensure that you only perform page

initialization logic when a page is first time loaded and not in response to

client postbacks.

12. Include Return Statements with in theFunction/Method

How it improves performance

Explicitly using return allows the JIT to perform slightly more optimizations.

Without a return statement, each function/method is given several local

variables on stack to transparently support returning values without the

keyword. Keeping these around makes it harder for the JIT to optimize, and

can impact the performance of your code. Look through your

functions/methods and insert return as needed. It doesn't change the

semantics of the code at all, and it can help you get more speed from your

application.

13. Use Foreach loop instead of For loop for String

Iteration

Foreach is far more readable, and in the future it will become as fast as

a For loop for special cases like strings. Unless string manipulation is a

real performance hog for you, the slightly messier code may not be worth it.

14. Avoid Unnecessary Indirection


When you use byRef, you pass pointers instead of the actual object.

Many times, this makes sense (side-effecting functions, for example), but you

don't always need it. Passing pointers results in more indirection, which is

slower than accessing a value that is on the stack.

Solution

When you don't need to go through the heap, it is best to avoid it there by

avoiding indirection.

15. Use "ArrayLists" in place of arrays


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An ArrayList has everything that is good about an array PLUS automatic

sizing, Add, Insert, Remove, Sort, Binary Search. All these great helper

methods are added when implementing the IList interface.

Tradeoffs

The downside of an ArrayList is the need to cast objects upon retrieval.

16. Always check Page.IsValid when using ValidatorControls

Always make sure you check Page.IsValid before processing your forms

when using Validator Controls.

17. Use Paging

Take advantage of paging's simplicity in .NET. Only show small subsets of

data at a time, allowing the page to load faster.

Tradeoffs

Just be careful when you mix in caching. Don't cache all the data in the grid.

18. Store your content by using caching


ASP.NET allows you to cache entire pages, fragment of pages or controls. You

can also cache variable data by specifying the parameters on which the data

depends. By using caching, you help ASP.NET engine to return data for

repeated request for the same page much faster.

When and Why Use Caching

A proper use and fine tune of caching approach will result in better

performance and scalability of your site. However, improper use of caching

will actually slow down and consume lots of your server performance and

memory usage.

Good candidate to use caching is if you have infrequent chance of data or

static content of web page.

19. Use low cost authentication

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Authentication can also have an impact over the performance of your

application. For example, passport authentication is slower than form-base

authentication which in here turn is slower than Windows authentication.

20. Minimize the number of web server controls


The use of web server controls increases the response time of your

application because they need time to be processed on the server side before

they are rendered on the client side.

Solution

One way to minimize the number of web server controls is by taking into

consideration, the usage of HTML elements where they are suited, for

example if you want to display static text.

21. Avoid using unmanaged code


Calls to unmanaged code are a costly marshaling operation.

Solution

Try to reduce the number calls between the managed and unmanaged code.

Consider doing more work in each call rather than making frequent calls to do

small tasks.

22. Avoid making frequent calls across processes

If you are working with distributed applications, this involves additional

overhead negotiating network and application level protocols. In this case,

network speed can also be a bottleneck. Try to do as much work as possible

in fewer calls over the network.

23. Cleaning Up Style Sheets and Script Files1. A quick and easy way to improve your web application's performance

is by going back and cleaning up your CSS Style Sheets and Script

Files of unnecessary code or old styles and functions. It is common for

old styles and functions to still exist in your style sheets and script files

during development cycles and when improvements are made to a

website.

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2. Many websites use a single CSS Style Sheet or Script File for the entire

website. Sometimes, just going through these files and cleaning them

up can improve the performance of your site by reducing the page

size. If you are referencing images in your style sheet that are no

longer used on your website, it's a waste of performance to leave them

in there and have them loaded each time the style sheet is loaded.3. Run a web page analyzer against pages in your website so that you

can see exactly what is being loaded and what takes the most time to

load.

24. Design with ValueTypes

Use simple structs when you can, and when you don't do a lot of boxing

and unboxing.

Tradeoffs

ValueTypes are far less flexible than Objects, and end up hurting

performance if used incorrectly. You need to be very careful about when you

treat them like objects. This adds extra boxing and unboxing overhead to

your program, and can end up costing you more than it would if you had

stuck with objects.

25. Minimize assemblies

Minimize the number of assemblies you use to keep your working set small. If

you load an entire assembly just to use one method, you're paying a

tremendous cost for very little benefit. See if you can duplicate that method'sfunctionality using code that you already have loaded.

26. Encode Using ASCII When You Don't Need UTF

By default, ASP.NET comes configured to encode requests and responses as

UTF-8.

If ASCII is all your application needs, eliminating the UTF overhead can give

you back a few cycles. Note that this can only be done on a per-application

basis.

27. Avoid Recursive Functions / Nested Loops

These are general things to adopt in any programming language, which

consume lot of memory. Always avoid Nested Loops, Recursive functions, to

improve performance.

28. Minimize the Use of Format ()

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When you can, use toString() instead of format(). In most cases, it will

provide you with the functionality you need, with much less overhead.

29. Place StyleSheets into the Header

Web developers who care about performance want browser to load whatevercontent it has as soon as possible. This fact is especially important for pages

with a lot of content and for users with slow Internet connections. When the

browser loads the page progressively the header, the logo, the navigation

components serve as visual feedback for the user.

When we place style sheets near the bottom part of the HTML, most browsers

stop rendering to avoid redrawing elements of the page if their styles change

thus decreasing the performance of the page. So, always

place StyleSheets into the Header.

30. Put Scripts to the end of Document

Unlike StyleSheets, it is better to place scripts to the end of the document.

Progressive rendering is blocked until all StyleSheets have been

downloaded. Scripts cause progressive rendering to stop for all content below

the script until it is fully loaded. Moreover, while downloading a script, the

browser does not start any other component downloads, even on different

hostnames.

So, always have scripts at the end of the document.

31. Make JavaScript and CSS External

Using external files generally produces faster pages because the JavaScript

and CSS files are cached by the browser. Inline JavaScript and CSS increase

the HTML document size but reduce the number of HTTP requests. With

cached external files, the size of the HTML is kept small without increasing the

number of HTTP requests thus improving the performance.

Tips For Database Operations

1. Return Multiple Resultsets

If the database code has request paths that go to the database more than

once, then these round-trips decrease the number of requests per second

your application can serve.

Solution

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Return multiple resultsets in a single database request, so that you can cut

the total time spent communicating with the database. You'll be making your

system more scalable, too, as you'll cut down on the work the database

server is doing managing requests.

2. Connection Pooling and Object Pooling

Connection pooling is a useful way to reuse connections for multiple requests,

rather than paying the overhead of opening and closing a connection for each

request. It's done implicitly, but you get one pool per unique connection

string. Make sure you call Close or Dispose on a connection as soon as

possible. When pooling is enabled, calling Close orDispose returns the

connection to the pool instead of closing the underlying database connection.

Account for the following issues when pooling is a part of your design:

1. Share connections

2. Avoid per-user logons to the database

3. Do not vary connection strings

4. Do not cache connections

3. Use SqlDataReader Instead of Dataset wherever it ispossible

If you are reading a table sequentially, you should use

the DataReader rather than DataSet. DataReader object creates a read

only stream of data that will increase your application performance because

only one row is in memory at a time.

4. Keep Your Datasets Lean

Remember that the dataset stores all of its data in memory, and that the

more data you request, the longer it will take to transmit across the wire.

Therefore, only put the records you need into the dataset.

5. Avoid Inefficient queries


Queries that process and then return more columns or rows than necessary

waste processing cycles that could best be used for servicing other requests.

Cause of Inefficient queries

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1. Too much data in your results is usually the result of inefficient

queries.

2. The SELECT * query often causes this problem. You do not usually

need to return all the columns in a row. Also, analyze

the WHERE clause in your queries to ensure that you are not returning

too many rows. Try to make the WHERE clause as specific as possibleto ensure that the least number of rows are returned.

3. Queries that do not take advantage of indexes may also cause poor

performance.

6. Unnecessary round trips


Round trips significantly affect performance. They are subject to network

latency and to downstream server latency. Many data-driven Web sites

heavily access the database for every user request. While connection pooling

helps, the increased network traffic and processing load on the database

server can adversely affect performance.

Solution

Keep round trips to an absolute minimum.

7. Too many open connections

Connections are an expensive and scarce resource, which should be shared

between callers by using connection pooling. Opening a connection for eachcaller limits scalability.

Solution

To ensure the efficient use of connection pooling, avoid keeping connections

open and avoid varying connection strings.

8. Avoid Transaction misuse


If you select the wrong type of transaction management, you may add

latency to each operation. Additionally, if you keep transactions active for

long periods of time, the active transactions may cause resource pressure.

Solution

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Transactions are necessary to ensure the integrity of your data, but you need

to ensure that you use the appropriate type of transaction for the shortest

duration possible and only where necessary.

9. Avoid Over Normalized tables

Over Normalized tables may require excessive joins for simple operations.

These additional steps may significantly affect the performance and scalability

of your application, especially as the number of users and requests increases.

10. Reduce Serialization

Dataset serialization is more efficiently implemented in .NET Framework

version 1.1 than in version 1.0. However, Dataset serialization often

introduces performance bottlenecks.

You can reduce the performance impact in a number of ways:

1. Use column name aliasing

2. Avoid serializing multiple versions of the same data

3. Reduce the number of DataTable objects that are serialized

11. Do Not Use CommandBuilder at Run Time


CommandBuilder objects such

as SqlCommandBuilder and OleDbCommandBuilder are useful when you

are designing and prototyping your application. However, you should not use

them in production applications. The processing required to generate the

commands affects performance.

Solution

Manually create stored procedures for your commands, or use the Visual

Studio® .NET design-time wizard and customize them later if necessary.

12. Use Stored Procedures Whenever Possible

1. Stored procedures are highly optimized tools that result in excellent

performance when used effectively.

2. Set up stored procedures to handle inserts, updates, and deletes with

the data adapter

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3. Stored procedures do not have to be interpreted, compiled or even

transmitted from the client, and cut down on both network traffic and

server overhead.

4. Be sure to use CommandType.StoredProcedure instead

of CommandType.Text

13. Avoid Auto-Generated Commands

When using a data adapter, avoid auto-generated commands. These require

additional trips to the server to retrieve meta data, and give you a lower level

of interaction control. While using auto-generated commands is convenient,

it's worth the effort to do it yourself in performance-critical applications.

14. Use Sequential Access as Often as Possible

With a data reader, use CommandBehavior.SequentialAccess. This is

essential for dealing with blob data types since it allows data to be read off of

the wire in small chunks. While you can only work with one piece of the data

at a time, the latency for loading a large data type disappears. If you don't

need to work the whole object at once, using Sequential Access will give you

much better performance.

Tips for ASP.NET Applications Developed using VB

1. Enable Option Strict and Option Explicit for your pages

With Option Strict on, you protect yourself from inadvertent late binding and

enforce a higher level of coding discipline.

2. Use early binding in Visual Basic or JScript code

Visual Basic 6 does a lot of work under the hood to support casting of objects,

and many programmers aren't even aware of it. In Visual Basic 7, this is an

area out of which you can squeeze a lot of performance.

Solution

When you compile, use early binding. This tells the compiler to insert a Type

Coercion is only done when explicitly mentioned.

This has two major effects:

1. Strange errors become easier to track down.

2. Unneeded coercions are eliminated, leading to substantial performance

improvements.

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3. When you use an object as if it were of a different type, Visual Basic

will coerce the object for you if you don't specify. This is handy since

the programmer does not have to worry about less code.

3. Put Concatenations in One Expression

If you have multiple concatenations on multiple lines, try to stick them all onone expression. The compiler can optimize by modifying the string in place,

providing a speed and memory boost. If the statements are split into multiple

lines, the Visual Basic compiler will not generate the Microsoft Intermediate

Language (MSIL) to allow in-place concatenation.

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Best Practices to Improve ASP.net Web Application Performance

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