Informix in Memory Windows

[Chris Riggins]

On an N4000-44 with 4 CPUs and 5 GB of RAM, running HP-UX 11.00, we have an user running (I believ) Informix 9.2 32-bit.

She cannot seem to start Informix within a memory window, and the 32-bit limitations on shared-memory space seem onerous.

Are Informix and Memory Windows oddly incompatible? Our Oracle instances (on other machines) don't have any problems.

Thanks.
Chris

[James Murtagh]

Hi Chris,

Although I haven't checked the release notes for that particular version on informix, they are not incompatible and I have seen informix run in a window.

What errors did you get?

Regards,

James.

[James Murtagh]

Hi Chris,

You don't need to recompile the kernel to disable memory windows - simply don't start the database in one?

I have a theory, but first can you provide the output from the following commands when the instance is not running in a window :

# ipcs -mob
# kmtune -l -q shmmax
# swlist -l product | grep -i windows

Also, can you confirm the contents of /etc/services.window and the setmemwindow command to start the database?

regards,

James.

[Chris Riggins]

Yes, I know that memory windows are _supposed_ to be invisible to processes when they're simply started normally (eg. without assignment to a window).

I've asked the DBA to provide more information on how she was starting the Informix instance (in or out of the memory window?), but haven't heard back yet.

[James Murtagh]

Hi Chris,

You've just sprung something to mind with your last response! It would be interesting to know if Informix didn't start even outwith the memory window but with memory windows set on in the kernel. Have memory windows configured (even if they are not used) does change the allocation algorithm for the shared quadrants space.

Regards,

James.

[JJ_4]

The engine came up succesfully after a full level 0 restore (presumably not in a memory window).

The engine was then attempted to be started (presumably within a memory window).

So, what changed in the startup?

=========================
11:32:35 Logical Recovery Complete.
11:32:36 Quiescent Mode
11:32:36 Logical Log 26767 Complete.
...
11:37:44 Informix Dynamic Server 2000 Stopped.

11:55:20 Informix Dynamic Server 2000 Started.
11:55:20 shmmax is configured too small to allow a single resident+virtual
+segment.
Multiple OS shared memory segments will be required
11:55:20 Could not create single shared memory segment with resident and
+non-resident partitions. Proceeding to create 2 shared memory segments instead.
11:55:22 Segment locked: addr=0x80000000, size=459812864
11:55:22 shmget: [ENOMEM][12]: key 52744802: out of shared memory, check system
+max shared memory segment size
=========================