Dear ART,

Thank you for your answer.

My Informix version is 10.00 UC6 (i know 9/2010 end of support...) On Linux
Box (RHL).

I would like to know, besides complex queries and sort, which other actions
could generate the increase on these segments? Views?
Is there any tool, besides Set Explain On (4GL), Trace on (SPL) that allows
me to see why these segments keep on increasing and why these virtual
memory segments are not liberated?.

Thank you,

Marcelo

---------- Forwarded message ----------
From: Art Kagel <art.kagel (AT) gmail (DOT) com>
Date: 2010/7/22
Subject: Re: Dynamically allocated new virtual shared memory segment
repeatdly
To: marcelo jaime <emetejota (AT) gmail (DOT) com>
Cc: informix-list (AT) iiug (DOT) org


You can release shared memory segments (except for the RESIDENT segment,
Message segments, and the first virtual segment) by running "onmode -F".
You don't state what version you are running, so I'll warn you that on some
IDS 7.3x/9.30 and earlier releases running onmode -F can sometimes crash the
engine especially if you run it often, so try it the first few times during
off times to make sure it is safe if you have an older version of Informix.

To prevent allocation of new memory resources, you have two choices:

- Expand the initial virtual segment size to include all of the extra
memory that's being allocated over time (SHMVIRTSIZE) or
- find the complex queries and sorts that are making the requests for
more memory and eliminate or simplify them.


Now, hitting the error 12 means that the OS would not give Informix any more
memory. That can be caused by several factors:

- The kernel parameter that controls how much memory a single process can
have is set too low. Solution: tune he kernel parameter (usually MAXMEM)
- The kernel parameter that controls how much shared memory a single
process can have or the number of shared memory segments a process can
attache to is set too low. Solution: tune the kernel (usually SHMMAX or
SHMNMN)
- You do not have enough physical memory plus swap to permit the engine
to allocate any more memory. Solution: buy and install more memory and/or
create more swap space.
- You are running a 32bit version of Informix and require access to more
than the 2-3 GB of memory that a 32bit process can address. Solution:
Upgrade to a 64bit version of Informix.


Art

Art S. Kagel
Advanced DataTools (www.advancedatatools.com)
IIUG Board of Directors (art (AT) iiug (DOT) org)

Disclaimer: Please keep in mind that my own opinions are my own opinions and
do not reflect on my employer, Advanced DataTools, the IIUG, nor any other
organization with which I am associated either explicitly, implicitly, or by
inference. Neither do those opinions reflect those of other individuals
affiliated with any entity with which I am affiliated nor those of the
entities themselves.



On Thu, Jul 22, 2010 at 4:02 PM, marcelo jaime <emetejota (AT) gmail (DOT) com> wrote: