1. Introduction to Object
Caching
Scott Cariss
Thursday, 20 June 13

2. What is it?
• Object caching is for caching data which
may be computationally expensive to
regenerate. E.G. a result from a complex
SQL query.
• You can have persistent and non-persistent
object cache.
• Object Cache can be stored in memory
(RAM), on disk or in a database.
Thursday, 20 June 13

3. Why use it?
• Speed improvement!
• Less wasteful
• Reduction in load on queried systems.
Thursday, 20 June 13

4. How to use it?
• WordPress comes with non-persistent object caching out of
the box with WP_Object_Cache(). Use wp_cache_get() and
wp_cache_set()
• If you want to use persistent caching then decide where you
want to store your object cache, in memory is the quickest.
• Install a WordPress persistent object caching plugin.W3 Total
Cache,WP File Cache and APC Object Cache to name a
few.
• If coding your own plugins and themes use wp_cache_get()
and wp_cache_set() to store and get data from the object
cache.
Thursday, 20 June 13

5. Demo
• Show a plugin that does computational
expensive queries to the database that
could benefit from a persistent object
cache.
• Show how to install APC object cache
plugin to WordPress.
• Re show the same plugin now using a
persistent object cache.
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6. Not using object cache
Thursday, 20 June 13

7. Using object cache
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8. Improvements
• Gone from a stats page taking ~19 seconds
to get results and display to ~1 second.
Thursday, 20 June 13