Re: Performance Testing

Elisa, Your email address elisa@ccserv.cc.nccu.edu bounces (or there's something up with our mail system)... Are you using OnLine? Which version? I'm not sure that there is a fixed limit on the number of users. You are constrained by the number of semaphores in the o/s kernel if you are using 4.x or 5.x; you are also constrained by the licence you bought (maybe, but not if it is unlimited, of course); and otherwise by the tbconfig or onconfig file. The locks are read & write locks and are limited to 256000, if I recall correctly. There are no login locks as such, though each database connection applies a lock to the database systables to prevent other users from gaining exclusive access to the database, and the number of semaphores is a limitation too. I'm not sure how big the biggest OnLine installation is, but I've certainly seen discussions about systems with many thousands (50+) of distinct users and several thousand concurrent users -- supporting that sort of system requires very powerful machines, needless to say. If your machine is big enough, you are unlikely to run into software limitations on the number of users. Yours, Jonathan Leffler (johnl@informix.com) #include <disclaimer.h> PS: The questions about version etc are rhetorical, though it is generally a good idea to quote version and platform (and product) when asking such questions. Note that the answer would be very different if you were using SE instead of OnLine. >From: elisa@ccserv.cc.nccu.edu (Elisa Chen) >Date: 13 Oct 1995 06:14:25 GMT >X-Informix-List-Id: <news.17888> > >I have a very critical problem here. How many users the Informix >DB engine can handle concurrently? In detail, how many read locks, >write locks, and login locks can be handled in the same time by >Informix DB engine? In what condition, the DB engine probably die. >Had anyone here done the pressure testing before for the Informix >DB engine? Because I runs an information system based on the Informix >DB now, I am afraid that the performance will go poor or down while >the number of users is up and the access frequencies is increased. >If anyone here have any experience on the problem, please give me >a hand. Thanks a lot!