Re: IBM AIX Kernel parameter limitations - HP seqment problem

Our numbers show that there is a 30% degradation in program performance between having one large shared memory segment and having 2. Mr. Lo - thanks for replying, my lack of hands on experimentation with AIX is showing. 2.5 GBytes is not an unreasonable limit for an instance of Informix. Anybody out there have a similar in depth understanding of HP's shared memory segment limitations?? So far my understanding of HP shared memory is: "For any given instance of HP-UX on any PA-RISC machine, more than 2 shared memory segments systemwide will lead to excessive processor interrupts to properly load the registers that contain the last 2 shared segment addresses referenced, resulting in drastically reduced throughput." Can anyone verify or debunk my perception of this? Thanks in Advance - Greg Mr Cheuk Kong Lo wrote: > > The ten segment limits exist on a single process (aka instance) because > the master oninit daemon allocates them at very initialization. If you > have multiple instances, then _each_ of these instances can have > (at max) 10 share memory segments. > > I've no problem in having 5 seperate instances on a single AIX machines, > for example. > > Of course, if you have a HUGE database, the current AIX v4.1/2 has the > limitation of 10x256MB share memory for your instance, but that's the > other issue... > > Chris snip.....