As we were findingslow page loading times on doc (45+ seconds sometimes) we decided to switch off feature_stats and feature_referer_stats to see what happens and that seems to have helped somewhat.
Annoyingly someone has changed the code so you can't actually stop tiki from trying to record "hits" information in the database and for each page load, and actually it tries to record a the same "hit" in tiki_pageviews, tiki_pages and tiki_stats and then also tries to do the same in tiki_files for each image and linked file on the page!
And since doc and dev were moved to using InnoDB storage this causes a huge bottleneck on writing to the database and thus seems to kill the performance on the site. I will try and add another pref or two to stop this madness but in the meantime i hope this helps anyone else finding their Tiki becoming unusably slow.
Generally for any site with a reasonable amount of traffic storing usage data in the same database is not a good solution, using log analysis tools and other applications such as Piwik is really the only way to go, i think.
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