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Sporadically onstat fails with Cannot attach to shared memory. errno = 22

  • 1.  Sporadically onstat fails with Cannot attach to shared memory. errno = 22

    Posted Tue December 15, 2020 09:00 AM
    Hi,

    i've the problem that sometimes (random) onstat commands fails with following error:

    14:53:31  shmat: [22]: operating system error
14:53:31  Client could not attach server shared memory segment, use IFX_XFER_SHMBASE.
MapViewOfFileEx: w32ec=487 at nt_shm.c:735
onstat: Cannot attach to shared memory. errno = 22​

    Errorlevel returned is 255.


    OS:
    Server 2019

    Informix:
    14.10FC5WE

    But the problem is accross all server and all informix versions since 14.10.

    I've tried it with different SHM settings, but the error apears everytime:

    #RESIDENT -1
RESIDENT 0

#SHMBASE 0x80000000L
#SHMBASE 0x141460000L
SHMBASE 0x150000000L

#SHMVIRTSIZE 6291456
SHMVIRTSIZE 1048576

#SHMADD 3145728
SHMADD 204800 #add in 200mb lots 

EXTSHMADD 8192
SHMTOTAL 33554432
SHMVIRT_ALLOCSEG 0,3

#SHMNOACCESS 0x70000000-0x7FFFFFFF​


    To reproduce the error you can use this cmd script:

    @echo off

set INFORMIXDIR=xxxxx
set INFORMIXSERVER=xxxx

:START
onstat.exe - >> onstat.txt 2>&1
echo ErrorLevel: %errorlevel% >> onstat.txt

if %errorlevel% neq 5 exit

GOTO START

    Sometimes the onstat is working ~30 times, sometimes ~300 times.

    I can't see a system here.

    Thanks.



    ------------------------------
    Josef Albert
    ------------------------------

    #Informix