Re: Online 7.x on IBM uni-processor

I have also found that Informix (which both uses multiple processes and multiple threads) count on a correct management of system signals. Shame, IBM AiX has reported a major bug in its "libpthread" system library which caused the Informix TCP/IP listener to hang, and caused Informix Server being waiting forever when attempting to stop it with "onmode -ky", requiring "kill -9" on all "oninit" processes, and "ipcrm" to remove shared memory segments and semaphores, before restarting the server. See the IBM RS6000 Web page for a free system fix (APAR) which solves the problem. Not all AiX systems exhibit this bug. Bill Ennis <ennis@ssax.com> a 'crit dans l'article <5ujt2c$r0j@cssun.mathcs.emory.edu>... > Informix version 7 and later is multi-threaded; whch means that it > can take advantage of multiprocessing. > > If you only have one processor you do not want to use the multiprocessing > capabilities. There is overhead involved with multi-threading an operation > since the threads will need to communicate with each other in order to get > the job done. > > Informix recommends that you not use multi-processor mode until > you have a machine that has at least 4 processors. > > The parameter in the onconfig file you need to be concerned with > is MULTIPROCESSOR (set it to 0). You should also set NUMCPUVPS=1. > > I would think that you would expect a multi-processor machine to perform > better than a single CPU machine so I wouldn't call that performance > degradation. > > -Bill > > > > We are running Informix systems on IBM RS6000s under AIX 4.2. We have to > > upgrade to Informix DSA v7.x to take advantage of the latest release of > > our application. > > > > We have heard that DSA, written for multi-processors, runs slower on a > > uni-processor (which is what we have). Has anyone any information on > > any potential performance degradation? > > > > David Kerslake > > > > > > > > > -- > Bill Ennis Voice: 312-474-7516 > SSA Fax: 312-474-7460 > 500 W. Madison email: ennis@ssax.com ennis@accesschicago.net >