Re: Performance Decreasing

In article <50q3hh$7ka@nntp1.best.com>, Lin-Chuan Lee <lclee@nntp.best.com> writes >Bill Ennis (ennis@ssax.com) wrote: >: Are you adding dynamic memory segments as the system is up? >: Run onstat -g seg. If you have many segments of type V when your >: system is slow this could be a signifcant part of the problem. > >: -Bill > >Is there a known bug that causes engine to add segments >when it shouldn't ?? I've never heard of that. >Assuming your machine has enough physical memory for application, >dynamic allocation of more memory shouldn't be causing >a slowdown, right ?? Is the 'right' thing to bump >up SHMVIRTSIZE ?? > >-Lin Yes, on my Informix Performance Tuning course I was told that having more than on segment of type V (virtual segment) reduces performance. Do onmode -F to free used memory pools/segments. Then count how much shared memory is in use, add 10% (to allow for heavy loads) and use this as SHMVIRTSIZE. Monitor with onstat -g seg say once a day and increase SHMVIRTSIZE if you get > 1 segment of class V. -- David Williams