Forum OpenACS Development: Re: NaviServer "breaks" under high load
~60 users is no load to be concerned of
I've read about your impressive WU-Wien installation...
However, with ~2.500 "total users" (using ]po[ at least once a week for hour logging, as opposed to these ~60 "active users" in the 2 min interval), also the number of "activities" (projects, tickets and tasks) go up more or less linearly. Most pages algorithms with at least n*log(n) complexity, so that overall load rises with at least n^3*log(n) with the number of users, probably even higher.
Right, this didn't make sense...
OK. I've now set maxthreads = minthreads = 32 and highwatermark=100 in order to disable dynamic thread creation.
The server has 8 physical cores. The "hang" occurred during re-spawning threads if I understood it right. So maybe just disabling dynamic thread creation might fix the situation.
We've got 15, 5 and 5 for pools 1, 2 and 3 respectively.
I'll have a detailed look at DB-connection stats next Friday.
It seems "hangs" have occurred so far only Fridays, because users seem to log hours for the week on Friday. Logging hours initiates some complex cache maintenance PG-triggers: Logged hours will create "cost items" which are attached to the respective activity. These items are rolled-up (aggregated) the project-activity-hierarchy towards the main project as part of a cache for the most important financial figures per project.