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ASP.NET Scalability - WebDD
This document discusses techniques for writing scalable ASP.NET applications, including caching output and objects to improve performance, using paging to reduce database loads, and minimizing network traffic by managing viewstate and compressing content. It provides an overview of various caching strategies like output caching, donut caching, and object caching using the caching API. It also covers reducing viewstate size and compressing content and JavaScript to reduce page size.
ASP.NET Scalability - WebDD
- 1. “This One GoesUp To 11” or How to write scalable ASP.NET Phil Pursglove phil@philippursglove.com http://diaryofadotnetdeveloper.blogspot.com http://www.philippursglove.com/ScalableASPNET http://twitter.com/philpursglove
- 2. About Me • Senior .NET Developer • MBCS • MCSD • VBUG East Anglia Co-ordinator • Written for VB Developer and SQL Server Pro
- 3. Agenda • Increasing serverperformance – Caching • Output caching • Donut caching • Object caching • Velocity – Paging • Reducing network loads – Managing ViewState – Compression
- 4. 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
- 5. Increasing Server Performance
- 6. Why Cache? • Becausethere’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!
- 7. 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
- 8. Caching 2: DonutCaching • 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
- 9. Caching 3: CachingAPI • Store objects in memory and pull them out when you need them • For data objects, you have to use DataSets and DataTables, not DataReaders
- 10. 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
- 11. 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
- 12. Paging • Default GridViewpaging 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
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- 14. ViewState 1 Viewstate Size Object in bytes HTML Table 52 DataList 6628 Repeater 6600 DataGrid 10592 GridView 10928
- 15. ViewState 2 • TamingViewstate – Can be disabled per-control – ZIP it up and put the zipped version on the page – Keep it on the web server
- 16. Compression 1 • Allmodern 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
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- 18. Compression 2 • JavaScriptCompression – JSMin (http://tinyurl.com/jscriptmin) – jQuery is pre-minified for you • CSS Compression – CSSMin (http://tinyurl.com/cssmin-webdd) – Written in PHP
- 19. Summary • Cache isKing! • Paging is good for your pages! • Viewstate doesn’t have to be evil!
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- 21. 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/
- 22. 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