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How to troubleshoot
WordPress performance
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Carl Alexander
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@twigpress
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carlalexander.ca
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Common situation
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Client:
WordPress is slow.
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Client:
Can you help?
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You:
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Load times are important
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But hard to debug
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Needle in a haystack
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Issue can be anywhere
(It really can!)
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Lots of tools available
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What’s a WordPress
performance issue?
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Slowness defines
performance issues
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Example:
Loading a page is slow
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Example:
Site search is slow
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Example:
Publishing is slow
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Example:
“Everything is slow”
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WordPress takes too long
to do something
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Frustrates the client
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Has a financial impact
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Where can you
find them?
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What happens when
you request a web page?
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Most obvious location
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Can be your code
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Can be plugin code
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Can be theme code
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Check PHP code
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Check JavaScript code
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Other common location
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Dozens of queries
on each page load
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Only takes one slow query
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Hard to diagnose
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Hardware and Software
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Varies from host to host
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Why picking
a good host is important
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Hard to diagnose as well
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Browsers are complex
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Lots going on between
requesting and rendering
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Can appear anywhere
between both points
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Questions?
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Browser tools
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Web developer tools
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Most important tool
at your disposal
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Available on all browsers
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Mandatory tool
for web development
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Console panel
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First panel to look at
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Shows error messages
and warnings
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Useful for rendering
performance issues
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But mostly for JavaScript
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Network Panel
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Look at waterfall first
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Scan for long bars
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Slow first request often
means issue with server
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Time To First Byte (TTFB)
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Time between request and
start of response
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One of the best metrics for
application performance
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Not a silver bullet
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Don’t forget summary!
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Web page
analysis services
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Questions?
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Server tools
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If nothing found in browser
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Problem is figuring out
where on the server
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Two sources of
performance issues
(Hardware and Software)
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Start with WordPress
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Query Monitor
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Best debugging
plugin for WordPress
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Collects all sorts of
information on WordPress
(More than just SQL queries!)
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Visible from the admin bar
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Visible from the admin bar
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Visible from the admin bar
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Visible from the admin bar
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Additional HTTP requests
can also slow things down
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Database server processes
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SQL query:
SHOW FULL PROCESSLIST;
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Additional tools
(But need access to your server)
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Slow logs
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MySQL tuner
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Application
performance monitoring
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Questions?
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Recapping
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How do you use
these tools together?
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Still stuck? Ask for help!
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Questions?
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Thank you!