Troubleshooting
Problem
When trying to use ontape utility to backup the logical logs the operation aborts with the following Assert Warnig message written in the online.log file: 16:55:01 Assert Warning: ISAM error: An error has occurred during logical log back up. 16:55:01 Who: Session(103919, xyz@hostname.com, 682, 0x68e24f14) Thread(104536, ontape, 68e0824c, 1) File: rsarcutl.c Line: 121 16:55:01 Action: isopen_logbu()/alloc_tQ() 16:55:01 Stack for thread: 104536 ontape
Symptom
The logical log backup is cancelled.
Cause
Out of virtual shared memory.
Diagnosing The Problem
The stack for thread ontape should look similar to this:
(oninit)afstack
(oninit)afhandler
(oninit)afwarn_interface
(oninit)oops_error
(oninit)isopen_logbu
(oninit)sqisopen_logbu
(oninit)tbj_open_logbackup
(oninit)tbj_archive
(oninit)sq_archive
(oninit)sqmain
(oninit)listen_verify
(oninit)spawn_thread
(oninit)startup
1) Use 'onstat -g seg' to check whether the total number of dynamically allocated shared memory segments reached the SHMTOTAL onconfig parameter value or if SHMTOTAL is set to 0 (zero), whether it reached the available physical memory.
2) Use 'onstat -g ses' to check for user sessions with large amounts of total and used memory values:
session #RSAM total used dynamic
id user tty pid hostname threads memory memory explain
103932 informix - 0 - 0 12288 7984 off
103931 informix - 0 - 0 12288 7984 off
103921 informix - 0 - 0 12288 7984 off
299862 informix - -1 localhos 1 192655360 41654376 off
383081 informix - -1 localhos 1 399044608 80636664 off
560221 informix 5 1572956 u169 1 49152 46376 off
Resolving The Problem
Find the sessions consuming large amounts of memory and therefore causing dynamic shared memory allocation and take actions.
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Document Information
Modified date:
01 June 2022
UID
swg21515051