ASP.NET Scalability - WebDD
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Transcript of ASP.NET Scalability - WebDD
“This One Goes Up To 11”or
How to write scalable ASP.NET
Phil [email protected]://diaryofadotnetdeveloper.blogspot.comhttp://www.philippursglove.com/ScalableASPNEThttp://twitter.com/philpursglove
About Me
• Senior .NET Developer• MBCS• MCSD• VBUG East Anglia Co-ordinator• Written for VB Developer and SQL
Server Pro
Agenda• Increasing server performance
– Caching• Output caching• Donut caching • Object caching• Velocity
– Paging• Reducing network loads
– Managing ViewState– Compression
What is Scalability?
• “The ability to handle growing amounts of work in a graceful manner” Wikipedia
• Scalability != Performance
• What affects scalability?
• Everything you see today applies to .NET 2.0 and higher
Increasing Server Performance
Why Cache?
• Because there’s a credit crunch!• Building a page is an expensive
process– Database calls across servers– Web Service calls– AD lookups
• Returning a stored page from a cache is much cheaper!
Caching 1: OutputCache
• Caches the rendered HTML from your page– Duration is in seconds– VaryByParam allows you to cache several
versions– Location means you can cache on the web
server, client, downstream machines or all of these
– CacheProfiles mean you have fine config-based control
– Cached pages can be removed with HttpResponse.RemoveOutputCachedItem
Caching 2: Donut Caching
• aka Post-Cache Substitution
• Inject dynamic content into a cached page before it is returned to the client– <asp:substitution>– Must use static methods with a
HttpContext
Caching 3: Caching API
• Store objects in memory and pull them out when you need them
• For data objects, you have to use DataSets and DataTables, not DataReaders
Caching 3: CacheDependency
• Objects in the cache can be dependent on other objects– When the dependency changes, the cached item
is removed– Not very useful in .NET 1.1
• .NET 2.0 introduced SqlCacheDependency– Cached objects can be dependent on SQL tables– Enable using the ASPNET_REGSQL tool– Or programmatically with the
SqlCacheDependencyAdmin object– Can integrate with OutputCaching
Caching 3: Velocity• Velocity
– Distributed cache• One logical cache split across several servers• PowerShell management console
– CTP3 released April 09• v1 Summer 09• SP1 Q4 09• v2 Summer 2010
– Doesn’t have dependencies – yet
– The future: automatic caching?
• See also NCache and memcached
Paging
• Default GridView paging behaviour reads the entire dataset every time– For 100 rows this probably isn’t going to matter– For 1 000 000 rows this probably isn’t so good
• Write your own paging mechanism• For custom paging DataGrids are better than
GridViews• In SQL 2005 the ROW_NUMBER function is
your friend!• LINQ
– Skip
Reducing Network Loads
ViewState 1Viewstate Size
in bytesObject
10928GridView
10592DataGrid
6600Repeater
6628DataList
52HTML Table
ViewState 2
• Taming Viewstate– Can be disabled per-control– ZIP it up and put the zipped version on the
page– Keep it on the web server
Compression 1• All modern browsers will accept
compressed content– Content is compressed on the server /
decompressed by the browser– Can be enabled in IIS
or– Use the HttpCompress library
Compression
Compression 2
• JavaScript Compression– JSMin (http://tinyurl.com/jscriptmin)– jQuery is pre-minified for you
• CSS Compression– CSSMin (http://tinyurl.com/cssmin-webdd)– Written in PHP
Summary
• Cache is King!• Paging is good for your pages!• Viewstate doesn’t have to be evil!
Any Questions?
Resources• Books
– Essential ASP.NET by Fritz Onion– The ASP.NET 2.0 Cookbook by Michael Gittel & Geoffrey LeBlond– The ASP.NET Anthology by Scott Allen et al
• PodCasts– http://www.dotnetrocks.com/default.aspx?showNum=24
– http://www.dotnetrocks.com/default.aspx?showNum=367
• MSDN White Paper on .NET Performance & Scalability
– http://msdn.microsoft.com/en-us/library/ms998530.aspx
• Strangeloop Networks Scaling Appliance– http://www.strangeloopnetworks.com/products/AS1000/
Resources• Velocity
– http://blogs.msdn.com/velocity– http://www.hanselman.com/blog/HanselminutesPodcast116DistributedCac
hingWithMicrosoftsVelocity.aspx– http://videos.visitmix.com/MIX09/T59F
• NCache– http://www.alachisoft.com/ncache/
• memcached– http://www.danga.com/memcached/
• Donut Caching– http://tinyurl.com/donutcaching
• HttpCompress Library– http://www.blowery.org/code/HttpCompressionModule.html