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shared memory full

Posted By: KAMRAN HAQ
Date: Monday, 13 January 2014, at 1:27 p.m.

Hi,
Today, memory of our informix instance increased from 2.5GB to 8GB within 9 minutes.
That instance is running with 2.5GB shared memory for around last 4 months.
8GB is defined as shmtotal so further requests for memory chunks overturned by the instance.
Usually we have session with a few KB memory to around 10MB memory.
Sorting the sessions on memory we got a session aquiring 1.83GB as can be seen below:

onstat -g ses

950863 appuser - -1 fmcpdbsp 1 9551872 9526088 off
955301 appuser - -1 fmcpappp 1 9908224 9822320 off
954997 appuser - -1 fmcpappp 1 9928704 9846984 off
945865 appuser - -1 fmcpappp 1 10002432 9965144 off
950909 appuser - -1 fmcpappp 1 10113024 10069920 off
947189 appuser - -1 fmcpappp 1 10407936 10399920 off
955492 appuser - -1 CASUN185 1 1971294208 1961083904 off
-bash-3.2$ onstat -g ses 955492

IBM Informix Dynamic Server Version 11.50.FC8W3 -- On-Line (Prim) -- Up 97 days 09:11:52 -- 8259584 Kbytes

session effective #RSAM total used dynamic
id user user tty pid hostname threads memory memory explain
955492 appuser - - -1 CASUN185 1 1981358080 1970916600 off

tid name rstcb flags curstk status
954290 sqlexec 15d3efb78 ---P--- 7855 running-

Memory pools count 2
name class addr totalsize freesize #allocfrag #freefrag
955492 V 14804b040 1982713856 10469440 2729374 37206
955492*O0 V 17568e040 4096 808 1 1

name free used name free used
overhead 0 6576 mtmisc 0 72
scb 0 144 opentable 0 238856560
filetable 0 6072 ru 0 600
misc 0 80 log 0 16536
temprec 0 21664 keys 0 736
ralloc 0 1524405528 gentcb 0 1712
ostcb 0 2816 sqscb 0 9639672
sql 0 72 rdahead 0 352
hashfiletab 0 552 osenv 0 2992
buft_buffer 0 2168 sqtcb 0 3177936
fragman 0 196105192 udr 0 168

sqscb info
scb sqscb optofc pdqpriority optcompind directives
16c105b88 133144028 0 0 2 1

Sess SQL Current Iso Lock SQL ISAM F.E.
Id Stmt type Database Lvl Mode ERR ERR Vers Explain
955492 SELECT inventory CR Wait 5 0 0 9.28 Off

Current Role : app_role

Current SQL statement :

Last parsed SQL statement :
SELECT 1 FROM SYSTABLES

WHERE TABID = 1

Operating system: Sun Solaris

The second largest session w.r.t. memory was holding 9.9 MB. We are unable to find or guess
where the rest of memory gone. Also:
how a session can consume so much memory?
if cummulative memory of session (through onstat -g ses) is consuming only 20% of total instance memory,
why we receing the messages in online log that no more memory chunks are allowed as shmtotal limit reached

Messages In This Thread

• shared memory full
  KAMRAN HAQ -- Monday, 13 January 2014, at 1:27 p.m.
  • Re: shared memory full
    Fernando Nunes -- Monday, 13 January 2014, at 1:35 p.m.

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