[drupal-devel] Drupal.org cache statistics

Steven Wittens steven at acko.net
Fri May 27 03:20:24 UTC 2005

> november last year, I profiled drupal.org's cache observations.   
> Yesterday, Moshe asked to profile it again so we could evaluate the  
> usefulness of Jeremy's "loose caching" mechanism.
> The past 20 hours, I logged 93.000 unique page requests using the  
> patch at http://buytaert.net/temporary/cache-statistics.patch.  Loose  
> caching was enabled.
> Results:
> 1. Last year we found that authenticated users were responsible for  
> 15,8 % of all page views.  A year later, we see that authenticated  
> users are responsible for 14,9% of all page views.
> 2. Last year we found that only 27.9% of the page requests actually  
> benefited from the cache system.  That is, for more than 2/3th of the  
> page requests, we had to generate a page dynamically.  A year later,  
> using "loose caching" rather than "strict caching", we see that 30,7%  
> of the page requests benefit from the cache system.  Read: we still  
> have a lot of page cache misses! :(

You have individual numbers for anonymous / authenticated, and for 
cached / not cached. But authenticated users do not get cached pages. Is 
that 27.9% / 30,7% figure the number of cache hits for all anonymous 
users, or for all users in general?

If it is for all users in general, then we can easily calculate the real 
page cache hit rate:
27.9 / (1 - 0.158) = 33,13%
30,7 / (1 - 0.149) = 36,07%

If my assumption is correct, these numbers are now not dependant on how 
many anonymous users / authenticated users we have. Not much difference, 
we can assume our distribution of anonymous users did not change much.

Steven Wittens

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