Joshua Eichorn discusses scaling WooCommerce sites. He explains that page caching is crucial for scaling WordPress sites and handling high traffic. However, personalization features can break caching. He suggests caching all pages by default and only bypassing the cache when users add items to their cart. For personalization, storing some data in cookies to handle personalization client-side is better. Properly sizing servers, splitting MySQL, and potentially scaling out caching and web servers are also important for scaling.

1. Joshua Eichorn, CTO CONFERENCE
SCALING
WOOCOMMERCE
Joshua Eichorn
CTO Pagely
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2. Joshua Eichorn, CTO CONFERENCE
WHO AM I?
‣ CTO of Pagely dealing with WordPress
at Scale every day
‣ Long time Open Source Developer,
PHPDocumentor, PEAR
‣ Lots of experience with PHP at extreme
scale at Stumbleupon
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3. Joshua Eichorn, CTO CONFERENCE
WHAT DO WE MEAN BY SCALE?
‣ High volume of traffic
‣ High volume of transactions
‣ Large product catalog
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4. Joshua Eichorn, CTO CONFERENCE
TODAY’S FOCUS
‣ High volume of traffic
‣ Large transaction volume is largely a sizing issue
‣ Large product catalog is largely unsolved. Normally this means importing
data, importer performance will be your main issue.
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5. Joshua Eichorn, CTO CONFERENCE
HAVE REALISTIC EXPECTATIONS
‣ Successful stores generate data (orders, products, reviews)
‣ Don’t expect to host a store for the same cost as a blog
‣ You will need more Mysql capacity: storage, memory, and CPU
‣ You will need more PHP capacity: CPU and memory
‣ You will likely want shell access so you can use WP-CLI for maintenance
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6. Joshua Eichorn, CTO CONFERENCE
SCALING WORDPRESS = PAGE CACHING
‣ WordPress scaling has generally focused on page caching using Nginx or
Varnish
‣ Most blogs are serving mostly static content
‣ Ecommerce isn’t that different, the majority of your product pages etc are
static content
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7. Joshua Eichorn, CTO CONFERENCE
PAGELY VPS CACHED
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8. Joshua Eichorn, CTO CONFERENCE
PAGELY VPS NO CACHING
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9. Joshua Eichorn, CTO CONFERENCE
PERSONALIZATION BREAKS CACHING
‣ Logged in users
‣ Showing the Cart status on every page
‣ Using a plugin that starts a PHP session
‣ Recommendations based on past purchases
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10. Joshua Eichorn, CTO CONFERENCE
PERSONALIZATION SHOULDN’T BREAK
CACHING
‣ Most sites use very minimal personalization
‣ Option #1: Cache pages unless a specific cookie is set, only set cookie
when an item is in the cart
‣ Option #2: Client side personalization
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11. Joshua Eichorn, CTO CONFERENCE
CACHE PAGES UNLESS A
SPECIFIC COOKIE IS SET
‣ WooCommerce sets the cookie for
you
‣ woocommerce_items_in_cart=1
‣ This is an easy solution, no template
changes needed
map $http_cookie $no_cache_cookie {
default 0;
"~woocommerce_" 1;
"~wordpress_" 1;
}
server {
listen 80;
proxy_cache CONTENT;
proxy_cache_min_uses 1;
proxy_cache_valid 200 30m;
location / {
proxy_no_cache $no_cache_cookie;
proxy_cache_bypass $no_cache_cookie;
proxy_set_header Host $host;
proxy_pass http://realserver:80;
}
}
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NGINX Example

12. Joshua Eichorn, CTO CONFERENCE
CLIENT SIDE PERSONALIZATION
‣ Store the data you need in a cookie
‣ Read the cookie on the client side, update UI
‣ This isn’t happening out of the box so it takes some work
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13. Joshua Eichorn, CTO CONFERENCE
WILL CACHING SOLVE EVERYTHING?
‣ Maybe
‣ What does your traffic look like
‣ The more successful you are at driving purchases the less helpful caching
is
‣ Use cache purging or low cache times or both
‣ Large catalogs lower cache hit rates
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14. Joshua Eichorn, CTO CONFERENCE
WHAT MAKES YOUR SITE SLOW
‣ Running PHP code (uses CPU)
‣ Talking to MySql (waiting)
‣ Talking to an Object Cache (waiting)
‣ Talking to external services (waiting)
‣ Doing fileIO (waiting)
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15. Joshua Eichorn, CTO CONFERENCE
THEME/PLUGIN CHOICES CAN MAKE
YOUR SITE UN-SCALABLE
‣ Showing 500 products on one page
‣ Dynamic menus that load every page in your site from the DB
‣ Calling a Facebook API on every page load
‣ Loading images over http to get there size
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16. Joshua Eichorn, CTO CONFERENCE
HOW TO SIZE YOUR SERVER
‣ PHP-FPM is easier to scale them mod_php
‣ # of workers hard limit is ram
‣ Useful limit is amount of CPU
‣ Run enough concurrent traffic to bring CPU to 100% (ab -c 2 http://localhost/)
‣ Once you reach this point, more workers are trading off speed for concurrency
‣ If that level of concurrency is less then you see in your logs on a regular basis
‣ You need a bigger server or you need to be faster
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17. Joshua Eichorn, CTO CONFERENCE
SCALING OUT VS SCALING UP
‣ Bigger servers are easier then many servers
‣ Many servers gets you added reliability as well as more scale
‣ On most cloud platforms it’s the same cost or cheaper to scale
up
‣ Splitting out Mysql makes sense in almost all cases, due to
different reliability needs
‣ Test splitting out object cache, usage is very round trip heavy, it
may be slower
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18. Joshua Eichorn, CTO CONFERENCE
SCALING OUT
‣ Scale out webservers:
‣ Direct traffic – Amazon ELB, Nginx, Varnish, Apache mod_proxy
‣ Sync files – DRBD, Lsyncd (Don’t use nfs)
‣ Scale out Mysql:
‣ Master + Read Slaves (doesn’t scale writes)
‣ Hyperdb DB drop-in
‣ Slave lag monitoring is important, HyperDb has examples
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19. Joshua Eichorn, CTO CONFERENCE
QUESTIONS
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20. Joshua Eichorn, CTO CONFERENCE
THANK YOU
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