onstat -g ses returns "Changing data structure forced command termination"

Hello, I installed a new informix server version IBM Informix Dynamic Server Version 14.10.FC9 running on a RedHat Enterprise Linux 8.4 VM machine. I noticed that every time i run the command onstat -g ses <sessionid>i receive the following message: Changing data structure forced command termination On informix log file i do not see any error or warning at the time that i execute the command. Note also that other commands eg. onstat -g ath, onstat -g ckp, onstat -g dis, etc. are displaying the expected output. I only face this issue specifically with onstat -g ses command.I found some old articles about this issue and they are mentioning a bug in informix if the client host which connects to the informix server has more than 8 characters in its hostname. I tested the above but the issue remains. Other suggestions mentioned that this output is displayed momentarily and if you try to run the command again the session information will be displayed but i tried to run the command repeatedly and i always get the same message. Is it a known bug on version 14.10? Is there any workaround or do i need to fix something in my onconfig file. If it is required i can post my onconfig file as well. Please advise. ------------------------------ Stavros Tseriotis ------------------------------ #Informix

Yup known bug in 14.10.FC9. Art ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------

Hello Art, Thank you for your prompt reply. Is there any other way to monitor the session information? ------------------------------ Stavros Tseriotis ------------------------------

Hello, This bug is fixed in specific 14.10.FC9X2 but in onstat from version 14.10.FC9X2 there is a couple of other onstat output problems with changing structure ( onstat -g top session cpu|bwr|bfw, onstat -g top sessmem gro which I observed) or incorrect output (onstat -x).We asked to fix as well. Milan Rafaj Infrastructure Architects & Specialists Teamleader Kyndryl Consult +420 737 264 248 www.kyndryl.com

Hello Milan, Are you aware if similar onstat bugs exists in 14.10FC8 as well? If not then maybe i will reinstall the server on FC8 instead. ------------------------------ Stavros Tseriotis ------------------------------

Stavros: You can query the SMI tables in sysmaster. The details span five tables or more however, so not trivial depending on what you need to see. The best documentation of what's in sysmaster is the sysmaster.sql script in $INFORMIXDIR/etc Some interesting tables include: syssesprof syssessions sysrstcb systcblst sysseswts syssessiontempspaceusage syssqscb sysconblock sysenvses sysscblst Art ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------

There are indeed some interesting tables in the sysmaster.sql. I found table syssqlstat which displays the query that is executed in the specified session. Maybe i can create a script using these tables. Thank you. ------------------------------ Stavros Tseriotis ------------------------------

I am afraid no, I did not test FC8 Milan Rafaj Infrastructure Architects & Specialists Teamleader Kyndryl Consult +420 737 264 248 www.kyndryl.com --

I ran 14.10.FC8 for a while, I did not see this issue with onstat there. Art ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------

Much appreciated! ------------------------------ Stavros Tseriotis ------------------------------

Hi, Do you have an APAR for that? Under what conditions does it occur? David. ------------------------------ David Williams ------------------------------

Hi, Do you have APARs for these? Under what conditions do they occur? Can someone from HCL comment on how this passed QA? Regards, David. ------------------------------ David Williams ------------------------------

David: I don't know the APAR. It happens with even a single client connection that has executed no SQL at all. Art ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------

IT42548 - onstat -g ses <sessid> throws "Changing data structure forced command termination." Thanks Manesh Informix Support ------------------------------ Maneshkumar Sivalingam ------------------------------

IT42548 ------------------------------ Maneshkumar Sivalingam ------------------------------

Thank you Manesh! Art Art S. Kagel, President and Principal Consultant ASK Database Management www.askdbmgt.com Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on 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.

Reproduced: $ onstat -g ses 68 IBM Informix Dynamic Server Version 14.10.FC9DE -- On-Line -- Up 00:37:23 -- 327812 KbytesChanging data structure forced command termination. Work-around: $ onstat-g-ses.sh 68 IBM Informix Dynamic Server Version 14.10.FC9DE -- On-Line -- Up 00:37:28 -- 327812 Kbytessession effective #RSAM total used dynamic id user user tty pid hostname threads memory memory explain ... Code: $ cat onstat-g-ses.sh# Work-around to IT42548 - Doug Lawry, Oninit Consulting, January 2023 case $1 in [1-9]*) sid=$1 ; shift exec onstat -g ses 0 "$@" | awk -v sid=$sid ' NR <= 5 { print } $1 == sid { found = 1 } found != 1 { next } /^-+$/ { exit } { print } ' ;; *) exec onstat -g ses "$@" ;; esac ------------------------------ Doug Lawry Oninit Consulting ------------------------------

Doug: Very cool! Works like a charm: $ onstat.g.ses 65 IBM Informix Dynamic Server Version 14.10.FC9DE -- On-Line -- Up 23:37:27 -- 1119364 Kbytes 2023-01-18 14:44:12session effective #RSAM total used dynamic 65 informix - 4 153001 Elezar-II 1 217088 197848 off Program : /opt/informix/infmx.14.10.FC9DE/bin/oninit tid name rstcb flags curstk status 84 CDRNsA1 44ae9150 ---P--- 3280 sleeping secs: 3 - Memory pools count 1 name class addr totalsize freesize #allocfrag #freefrag 65 V 48762040 217088 19240 75 12 name free used name free used overhead 0 3352 scb 0 144 opentable 0 5992 filetable 0 1016 log 0 16536 temprec 0 120992 ralloc 0 9632 gentcb 0 1592 ostcb 0 2992 sqscb 0 24856 hashfiletab 0 552 sqtcb 0 8752 fragman 0 720 sapi 0 144 cdr 0 576 sqscb info scb sqscb optofc pdqpriority optcompind directives 44ca91c0 487c5028 0 0 0 1 Sess SQL Current Iso Lock SQL ISAM F.E. Id Stmt type Database Lvl Mode ERR ERR Vers Explain 65 syscdr CR Not Wait 0 0 9.03 Off ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------

Hi, Do you have APARs for these? I did not see these in the fix list for 14.10.FC9W1, can you test on that version? Regards, David. ------------------------------ David Williams ------------------------------

David: Yes the fix for this os included on 14.10.FC9W1 Art ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------

idsdb00111503 IDS-14.10.XC9W1 onstat -g ses <sessid> throws "Changing data structure forced command termination."Validated November 28, 2022 8:44:35 AM CST IT42548 TSUPP ONUTILS-ONSTAT This is taken from the fixlist MARCUS HAARMANN

HI, I was asking about: " there is a couple of other onstat output problems with changing structure ( onstat -g top session cpu|bwr|bfw, onstat -g top sessmem gro which I observed) or incorrect output (onstat -x).We asked to fix as well." Do we have APARs for these? ------------------------------ David Williams ------------------------------

Hello David, some of them yes (onstat -g ses <sid>, onstat -x some of them not yet: onstat -g top session cpu IBM Informix Dynamic Server Version 14.10.FC9W1DE -- On-Line -- Up 00:07:22 -- 6603536 Kbytes 2023-02-23 15:33:43Top Resource Usage (Max lines 10, Time interval 5 seconds): Top sessions (CPU usage) -------------------- sid CPU_time 93 0.0031 Errors found in session block list. May be caused by changing data structures. ... onstat -g top session bfr IBM Informix Dynamic Server Version 14.10.FC9W1DE -- On-Line -- Up 00:11:47 -- 6603536 Kbytes 2023-02-23 15:38:08Top Resource Usage (Max lines 10, Time interval 5 seconds): Top sessions (buffer reads) ----------------------------- sid bfrd bfwrt 101 3 2 Errors found in session block list. May be caused by changing data structures. ... onstat -g top session bfw IBM Informix Dynamic Server Version 14.10.FC9W1DE -- On-Line -- Up 00:13:00 -- 6603536 Kbytes 2023-02-23 15:39:21Top Resource Usage (Max lines 10, Time interval 5 seconds): Top sessions (buffer reads) ----------------------------- sid bfwrt bfrd 101 8 12 Errors found in session block list. May be caused by changing data structures. ... For some could not get data: onstat -g top sessmem gro IBM Informix Dynamic Server Version 14.10.FC9W1DE -- On-Line -- Up 00:14:20 -- 6603536 Kbytes 2023-02-23 15:40:41Top Resource Usage (Max lines 10, Time interval 5 seconds): (No session pool growth to display) Regards ------------------------------ Milan ------------------------------