INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10

A database operation that quickly consumed gigabytes of memory
caused the maximum number of segments to be allocated and ~16GB
more than SHMTOTAL (~14GB) to be allocated.

While we do not know the exact work executed by the offensive
session, the memory growth was far too excessive to be deemed
intentional by the low memory manager.

In this case, the excessive allocation was partially consumed by
lock allocation and the final segment allocated was quickly
followed by a lock table overflow assertion as the server could
not grow the lock table:

Forcing new segment size to 16Mb and non resident.
Exceeding SHMTOTAL because Low Memory Manager is on.
Dynamically allocated new virtual shared memory segment (size
16384KB)
Memory sizes:resident:71304 KB, virtual:14569956 KB,
SHMTOTAL:14624874 KB

< this continues for over 1000 segment allocations in only a few
seconds until...>

Forcing new segment size to 16Mb and non resident.
Exceeding SHMTOTAL because Low Memory Manager is on.
Dynamically allocated new virtual shared memory segment (size
16384KB)
Memory sizes:resident:71304 KB, virtual:31183332 KB,
SHMTOTAL:14624874 KB

Error: Number of Informix segments exceeds maximum allowed: 1024

Assert Warning: Lock table overflow - user id 204, session id
245255
IBM Informix Dynamic Server Version 
                Who: Session(245255, user@host, 18631,
0x4bdcc0a8)
                Thread(379208, sqlexec, 4bd99f08, 8)
                File: rslock.c Line: 3632
                Results: Memory allocation error.

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 12.10.xC14 and 14.10.xC4.  *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Update to Informix Server 12.10.xC14 or 14.10.xC4 (when      *
* available).                                                  *
****************************************************************

****************************************************************
* USERS AFFECTED:                                              *
* Users of Informix Server prior to 12.10.xC14 and 14.10.xC4.  *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Update to Informix Server 12.10.xC14 or 14.10.xC4 (when      *
* available).                                                  *
****************************************************************

Fixed in Informix Server 12.10.xC14 and 14.10.xC4.

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

10.12.2019
04.03.2020
04.03.2020

12.10.xC14,
14.10.xC4