Performance Troubleshooting EPiServer CMS Web Sites

Steve Celius – EPiServer Geek

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The Different Approaches to Performance

» This presentation focuses on troubleshooting existing sites with performance problems- Finding the cause and what you can do about it- The tools you need, and the common causes

» Performance is much much more- Clientside (everything not in your aspx) can be 80% of the

download time (when you’re not having server trouble)- I’ll cover this the next time

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The cost of fixing performance problems

Content Infrastructure CodeLow

Intermediate

HighCost

Thanks to Stuart Tuppert

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Finding the slow parts of your site

» Analyse IIS Logs- Check time_taken, # requests per hour / min (find the peaks)- Check for errors (404 / 500 status)

» LogParser & Visual Log Parser- Find the most requested pages- Find errors and long running requests- Easier with Visual LogParser

» Use Fiddler

» Performance Monitor- Lots of information on the net- Check cpu, req/s and req. queue

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Common Performance Problems

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The Large List Problem

» Large collections of pages will kill performance

» Understanding the cache is important- GetPage / GetChildren gets copies of PageData objects- Memory and CPU intense (lots of allocations and deallocations)

» Dynamic Properties – are they really neccessary?

» Pages with large strings (MainBody) is also a problem

» News archives will slowly kill your site

» Edit mode, expanding the tree loads two levels

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Key Points

» The devil is in the details- You don’t TRULY know until you have profiled

» Things changes with content- What does not hurt you today might hurt you tomorrow

» Make sure you optimize the important things

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Fixing it!

» Split up page lists with more then 250 pages into subtrees- Why 250? Practical reasons for editors- Use ”Date Containers” (/News/2007/June/My-news-article)- Moving pages using code is easy

• You don’t even need to recompile (no code behind file neccessary). See ArchiveBuilder.aspx

• If there are many pages, it will take some time

» Cache the list

» Move Dynamic Properties to the Start Page

» This problem has less impact in CMS 5

Easy Fix

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FindPagesWithCriteria (FPWC)

» The most resource intensive operation in EPiServer

» Very useful, and most sites need it

» It will search the database, returning all pages that match the criterias

» ”With great power comes great responsibility”

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Fixing it!

» Use log4net to detect FPWC calls- Log all FPWC calls to one file, with page id and search ref

» Limit the use of FPWC- Always think of alternative solutions- Limit the count of returned pages. The database call is not the

problem, working with a large resultset is

» Cache what you can cache- Enter EPiCode Cache Framework...

Medium Fix

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EPiCode Cache Framework for EPiServer 4

» All sites will have some complex and/or heavy queries (not only FPWC)

» You should recognize them when you write the code

» Prevent these queries to run too often, cache the result

» Designed for low impact on existing code

» Download from:- www.coderesort.com/p/epicode/wiki/CacheFramework

Medium Fix

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Use output caching

» Configurable, turn on in web.config

» Will cache the html output from your pages

» Can give you extreme performance

» Whole cache is invalidated on page publishing

» Not available for logged in users and POST

» ”VaryBy” – don’t vary by browser if you do not have to

» /3GB in boot.ini (?)

» It won’t fix your problems though

Easy Fix

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Beware of what you cannot see

» RSS Feeds in particular- Long lists, requested often- Check the IIS log file- Use the cache framework

» Bots, Crawlers and Spiders- They might fill our output cache- Will visit the ”uninteresting” pages, like the sitemap and news

archive. Pages you hope no one visits

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Scale out

» Buy more hardware

» Load balance on several servers

» Especially if the load is the problem

» Requires cache invalidation and file sync

» Session state (are you using it?)- State Server or SQL Server

Expensive Fix

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Migrate to EPiServer CMS 5

» You will need to rewrite some of the code

» The Migration Tool helps with data migration- This is another presentation altogether

» See Marek Blotny’s excellent blog post on EPiServer 5 vs. EPiServer 4.61- CMS 5 scales much better

Expensive Fix

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Important Tools

» Fiddler

» JetBrains DotTrace

» WebLoad / Jmeter / WAPT Load Testing

» log4net

» Trace Diagnostics

» IIS Diagnostics

» ASP.NET Viewstate Helper

» Performance Viewer (Windows)

» LogParser & Visual Log Parser

» IIS Traffic Monitor

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» Special offer to all EPiServer Developer Summit 2008 attendees

» Extended trial period (10 30 days)

» Offer lasts for 30 days – from now!

» Read more, download evaluation and order on:http://www.jetbrains.com/profiler

» Eval and Coupon code:

15%

b4zLrhD/g23bNieHrY8oV6EIezUiCzad

Discount

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Misc...

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Release Mode

» Compile the site in Release Mode (in VS)

» <compilation debug=”false” /> in web.config

» This will give you ~10% performance gain

» ASP.NET will not time out with debug = true- Just as important as the performance gain

» WebResources.axd scripts can be cached

» Site will use less memory

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Enterprise Gotcha

» Same source code, many different web sites- One place to deploy code- One config file to update

» But...- Config changes will restart all sites

• This is heavy lifting!

- Logging with log4net is a pain• All sites uses same config, with file locking, first site to start ”wins”.

Without locking, log file is a mess

- One change affects all sites, needs recompiling

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Enterprise Gotcha, contd.

» Use deployment scripts to copy files to all sites- With delays to allow recompilation and startup peaks- This also goes for web.config

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IIS Settings

» Log more- Review the IIS log settings. Turn on most log settings- Remember ”time-taken”

» Process Recycling – dont rely on it- It will only help on memory or resource leaks, temporarily- More often used on .NET 1.0/1.1 sites than 2.0 and up

» Web Gardens- No, no and no! It can actually hurt performance

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Minimize Viewstate

» Think Green - Save Bandwidth

www.binaryfortress.com/aspnet-viewstate-helper

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Links

» Performance Tuning and Optimization of EPiServer CMS (Fredrik Haglund)

» EPiServer 5 vs. EPiServer 4.61 part I - GetPage() (Marek Blotny)

» The challenges of a high traffic site with EPiServer (Adam Najmanowicz)

» Performance Pitfalls in EPiServer (Mats Hellström)

» The Output Cache - When and Why (Daniel van den Tempel)

» Caching Custom Data in EPiServer

» EPiServer Labs

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Per Request Cache

» Don’t do expensive operations more than once in a request

» Example:- Checking if the current page is in a given structure

» Refactor into utililty methods

» Keep the impact on existing code low

» Store in HttpContext.Current.Items- Request bound, thread safe

Medium Fix

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IIS Traffic Monitor

» Analyses IIS log files on the fly

» Simple and quick to use

» Uses Log Parser 2.2

Tool

http://niknak.org/software/IIsTrafficMonitor

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Use Fiddler to see real traffic

» Server performance is important, but don’t neglect the client side performance

» Check the Yahoo Performance Blog (and YSlow)- Percieved performance is also important!

» Make sure the clients cache effiently

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