outsystems - when it's slow it sucks: lessons from the trenches - nextstep 2012
DESCRIPTION
Knowing your application has a performance problem is half the battle. Fixing the problem typically falls into one of several categories. In this session learn from performance problems encountered across the OutSystems ecosystem and the approach taken to find and address each issue.TRANSCRIPT
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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…
