topic Problem clearing shared memory segments on HP 10.20 in Operating System - HP-UX

Problem clearing shared memory segments on HP 10.20

Alyx Chavis_1 — Thu, 13 Jan 2000 18:39:57 GMT

We have a system with two Informix instances. When the second one has to be
taken down one or more of the shared memory segments will not clear. This
prevents Informix from coming back on-line because it cannot access the memory
it needs. We end up having to reboot the machine to clear the segments. It is
not a situation where a shemaphore has remained and the segment cannot be
removed with ipcrm. It cannot be traced back to a active process either. My
thought is the O/S is not letting the segment go when all processes have been
removed. Has anyone encountered this problem and/or is there a related patch
or bug?

Thanks,
Alyx

Re: Problem clearing shared memory segments on HP 10.20

Simon Waters_2 — Fri, 14 Jan 2000 13:56:58 GMT

I didn't think the OS did clear shared memory, merely because all the processes
referencing it had died.

I thought that it had to be explicitly deallocated, or removed as you
described.

Re: Problem clearing shared memory segments on HP 10.20

Julio Garcia_4 — Mon, 17 Jan 2000 13:23:24 GMT

Excuseme my poor english.
I have I-DSA 7.24.
When you have two instances of informix, you should to identify the segment of
shared memory of very instance, revise the page 12-12 of the manual
Informix-Online Dynamyc Server Administrator's Guide, Volume 1 Version 7.1 and
then remove all the segments similar to the calculate value according to manual
using ipcrm -m.