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When It's Slow it Sucks
Lessons Learned From the Trenches
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Good applications have at least one thing in common: they are really fast.
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built-in agileplatform™
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viewstate reduction through R/W analysis partial screen rendering through visual AJAX
automatic AJAX queuing smart prevention of duplicated AJAX requests
automatic end-users activity monitoring
user interface logic database
agileplatform™
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unlimited horizontal scalability built-in distributed session management
automated batch processing scaling batch processes instrumentation & monitoring
integrations instrumentation & monitoring automatic monitoring of all errors
built-in logs rotation persistence of logs in bulk
asynchronous logging through messaging
user interface logic database
agileplatform™
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database connection pooling unused database connections unloading
optimized !elds fetch optimized dataset memory load
queries automatic instrumentation & monitoring primary & foreign keys automatic indexing
user interface logic database
agileplatform™
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Beyond built-in agileplatform™ optimizations,
keep these performance best practices in mind.
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la Palisse truth
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• Creating indexes for the most used entity attributes will signi!cantly improve the performance of select queries
– at the cost of slight overhead in insert and update operations.
la Palisse truth #1 Index your entities
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Lesson Learned From the Trenches
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Lesson Learned From the Trenches #1 Monitor your indexes
Uncover Hidden Data to Optimize Application Performance (Ian Stirk) http://msdn.microsoft.com/en-us/magazine/cc135978.aspx
SQL Server
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• Costly Missing Indexes – Indexes that you may consider adding
• Unused Indexes – Not needed indexes (they hurt performance too)
• Costly Used Indexes – Indexes hurting insert / update operations
Lesson Learned From the Trenches #1 Monitor your indexes
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• Reorganization of indexes and statistics update – Don't forget to involve the resident DBA.
la Palisse truth #2 Setup database maintenance plan
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the maintenance plan was being executed but…it was
stopping due to an error Inevitably, this was leading to performance degradation.
Lesson Learned From the Trenches #2 Ensure execution is being monitored
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• Avoid the use of 2000+ characters in a text !eld. – Data !elds greater than 2000 bytes are converted into a Text data
type.
• As a rule, isolate binary and/or large text !elds in separate entities
– And only retrieve them when they are strictly necessary
la Palisse truth #3 Isolate large text and binary data
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• allows fast and "exible indexing for keyword-based querying of text data
• also, To search inside the binary !les stored in database using I!lters
How-to install, con!gure and use Full Text Search agile network
Lesson Learned From the Trenches #3 Use Full-Text Search
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• Cross server joins are very inefficient. – The table in the linked server is completely loaded to the local DB in
order to perform the join.
• May be acceptable if the tables are small and unavoidable.
la Palisse truth #4 Don't join over linked server
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• Apply the recommended settings from the installation checklist.
la Palisse truth #5 Con!gure web server memory settings
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• Affects user experience, therefore should be simple and fast to execute.
• Also avoid using functions accessing the DB in Table/List Records.
la Palisse truth #6 Simplify screen preparations
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• Increases network traffic between the server and the browser.
la Palisse truth #7 Avoid using preparation data in screen actions
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• Use Service Studio’s build-in caching features (5.1+): – Queries – Actions
– Web blocks – Screens.
la Palisse truth # 8 Cache, baby, cache
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What about the lessons?
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la Palisse…The obvious
• Index your entities • Setup database maintenance plan • Isolate large text and binary data • Don't join over linked server • Con!gure web server memory settings • Simplify screen preparations • Avoid using preparation data in screen actions • Cache, baby, Cache
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80% of the end-user response time is spent on the browser
• downloading all the components in the page:
images, .css, scripts, flash, …
• The goal: Reducing the number of components in turn reduces the number of HTTP requests required to render the page
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Let’s start with…
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• The preferred method for reducing the number of image requests.
• Group multiple images together (usually icons or decorative images) into one sprite.
• Position the sprite to display the appropriate image by shifting the X or Y position by a multiple of the spacing.
Lesson Learned From the Trenches #4 CSS sprites
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Lesson Learned From the Trenches #4 CSS sprites
Enjoy the increased speed and reduced HTTP requests.
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• Moving stylesheets to the document HEAD makes pages appear to be loading faster, it allows the page to render progressively
• The problem with putting stylesheets near the bottom of the document is that it prohibits progressive rendering in many browsers
• Some browsers block rendering to avoid having to redraw elements of the page if their styles change.
Lesson Learned From the Trenches #5
Put Stylesheets at the Top
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• The problem caused by scripts is that they block parallel downloads.
• The HTTP/1.1 speci!cation suggests that browsers download no more than two components in parallel per hostname.
• While a script is downloading, the browser won't start any other downloads.
Lesson Learned From the Trenches #6
Put Scripts at the Bottom
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Lesson Learned From the Trenches #7 Minify CSS / JS !les
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Lesson Learned From the Trenches #7 really…minify it!
minifyjs.com jscompress.com
…
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• JavaScript and CSS !les are cached by the browser.
• JavaScript and CSS that are inlined in HTML documents get downloaded every time the HTML document is requested. – reduces the number of HTTP requests needed – increases the size of the HTML document.
Lesson Learned From the Trenches #8
Make JavaScript and CSS External
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Lessons Learned From the Trenches
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• Monitor your indexes • Ensure Database maintenance is being monitored • Use Full-Text Search • CSS sprites • Put Stylesheets at the Top • Put Scripts at the Bottom • Minify CSS / JS !les • Make JavaScript and CSS External
To keep in mind
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http://www.!ddler2.com/ http://yslow.org/ https://developers.google.com/speed/pagespeed/ http://www.websiteoptimization.com
search for…
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• How to tune the TCP/IP stack for high volume of web requests agile network
• Secrets to Building High Performance Apps nextstep11 presentation
• Spriting made easy http://spriteme.org/
• Automatic Performance Optimizations http://www.outsystems.com/demos
also search for…
