Re: Shared Memory/Semaphore Parameters for Sun 670 ??

A. J. Dibbins writes: |> Can anybody help with more information on the relationship between the |> semaphore parameters SEMMNI, SEMMSL and SEMMNS. The manual says |> Online uses one semaphore per database engine process so SEMMNS should |> equal the number of users + 4, for us about 80, anyway it is currently set |> as above, 640 (plenty) and SEMMSL should be at least 25, well it is set |> equal to SEMMNS according to "sem.h" so what about SEMMNI ? SEMMNI specifies the number of set identifiers in the kernel. This is the number of semaphore sets that can be active at a given time. In theory, SEMMNI*SEMMSL should be equal to SEMMNS. You current config allows as many semaphores as are available (SEMMNS) to be in a single set if need be (if indeed SEMMSL == SEMMNS). I don't know how many semaphores OnLine is putting in a set on your system. ipcs -s should show the sets and the semaphores per set allocated. It may be that you need more sets available (assume at least one set per online instance, though it may need more). Also note that 640 for SEMMNS means 640 OnLine users can be supported across all the online instances. So for example if you have 5 instances each tuned to support 20 users you would need 100 semaphores. Dave Disclaimer: The opinions expressed in this message are not those of Informix Software, its partners or lackeys. Anyone who says otherwise is itching for a fight. **************************************************************************** "I look back with some satisfaction on what an idiot I was when I was 25, but when I do that, I'm assuming I'm no longer an idiot." - Andy Rooney