Thanks Dries. Wow. This is disappointing and a bit confusing. How can we interpret the seemingly contradictory changes described in 2 vs. 3? I have to believe we can get more than 30% cache hits when our user base is 85% anonymous. Part of me wonders if we are not getting skewed results because of web crawlers. Thos crawlers spider all of our obscure pages and thus cause cache misses. I agree that we need to work on the non cached case. -moshe Dries Buytaert wrote:
Hello world,
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! :(
3. Last year, we found that the cache got flushed once every 207 page requests. A year later, we observe that the cache got flushed once every 190 page requests.
We conclude that:
1. Loose caching does not significantly -- or not necessarily -- improve the behavior of drupal.org's page cache (though I'd like to believe that it does when there are sudden traffic spikes/bursts).
2. When writing code, we can NOT assume that a page will benefit from being cached.
-- Dries Buytaert :: http://www.buytaert.net/