I run a fairly large (+50k unique users a month, +110k accounts, +5k active courses), we recently upgraded to 2.6 from 2.5. We're using memcached for application + session caching. There are 4 webservers running a memcached pool for the application cache, and 2 databases (master/slave) that have memcached running for sessions.
Since the upgrade to 2.6 we've noticed almost double the response time for viewing /moodle/my, has anyone else experienced this or know a patch/solution?
We've profiled the page loads and page loads of /moodle/my are taking upwards of 4500ms (in 2.5 we were rarely in excess of 3000ms, 99.5% of loads were at <800ms), where 90% of that time is spent on multiple calls to "get_fast_modinfo" by "get_all_instances_in_courses" (assign/lib.php ~306) from "assign_print_overview" (blocks/course_overview/localib.php ~43) from "block_course_overview_get_overviews" (blocks/course_overview/block_course_overview.php ~75).
It's my understanding that the 2.6 upgrade removed modinfo from the course table to instead move it to the MUC, which seems to actually be a performance hit for us.
EDIT: We've also noticed occasional large response times in "core\session\handler::start - session/memcached.php:96" (+30 seconds).