[wp-hackers] RE: apache 2.2.2 upgrade

[Mark Jaquith]

On Jul 14, 2006, at 11:20 PM, Scot Hacker wrote:

> So I've inferred that caching is fully present and working.
>
> But I also  keep seeing references to WP-Cache 2, as if caching   
> were NOT already present in WP 2.
>
> What's the real caching deal?

WP 2.0+ includes an object-caching system.  It caches data objects  
frequently used by WP, e.g. user data, category data, page data.  The  
system is pluggable, but has built-in support for caching to the  
filesystem.  This system was enabled by default in 2.0 and 2.0.1

In 2.0.2, it was turned off, because certain setups were causing  
problems.  So now it has to be intentionally enabled in wp-config.php  
in order to work.

This system, no matter what backend it uses (there are drop in  
backends for APC and Memcached), is not a substitute for WP-Cache2.   
The benefits of the built-in object cache are small, but WP-Cache2  
can give you several orders of magnitude more page-serving power,  
because it caches the HTML output of pages for a particular URL +  
Cookie combination.  Cached hits use no DB calls and very little  
processing power (as WP isn't fully loaded for the hit).

Both systems offer speed and throughput benefits, and complement each  
other, as they cache different things.  The built-in cache speeds up  
your dynamic hits, and WP-Cache2 caches your dynamic hits so that  
subsequent hits use fewer resources.
--
Mark Jaquith
http://txfx.net/