dbaccess starts eating 100% CPU when terminal session closed abruptly on RedHat
Jose Ruiz reported that interactive dbaccess keeps running at 100% CPU after a PuTTY window is closed abruptly on RedHat. Andreas Legner said it is a known problem, also seen on SuSE and AIX, and recommended opening a support case. Jose opened one and reported APAR IT46691 now covers dbaccess surviving loss of its terminal.
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Hi everybody,
When running dbaccess (in interactive menu mode) on RedHat, if you just close the putty terminal window abruptly, dbaccess process keeps running and using up 100% CPU.
Top output shows:
The process hierarchy survives pending from process with pid 1,(init) and with no terminal attachment.
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root 1407447 1 0 09:13 ? 00:00:00 sudo su - informix
root 1407448 1407447 0 09:13 ? 00:00:00 sudo su - informix
root 1407449 1407448 0 09:13 ? 00:00:00 su - informix
informix 1407450 1407449 0 09:13 ? 00:00:00 -bash
informix 1409593 1407450 84 09:16 ? 00:03:28 dbaccess
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A "kill 1409593" will just end up the whole hierarchy.
Closing the terminal window without dbaccess running will end up the ps hierarchy correctly.
Using strace on the running dbaccess shows it is running an infinite loop doing
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read(0, "", 1) = 0
read(0, "", 1) = 0
read(0, "", 1) = 0
......
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This is happenning on RedHat only. Tested on SuSE and on HP/UX and dbaccess and everything else gets closed correctly on the linux/unix side.
I have checked stty -a and terminal config is exactly the same on RedHat and SuSE.
Any insight here much appreciated,
Best regards,
Josem
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Jose Ruiz
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Hi Jose, this is a known problem, bugging us too from time to time (test machines getting really slow), only no one so far got around to really fixing it and perform the required regression testing. -> if you need this fixed, I'd recommend opening a support case and request the fix Also: I cannot confirm this is anyhow RedHat specific, we're seeing it on SuSE too, and I just repro'ed it on AIX. ------------------------------ Andreas Legner ------------------------------
Support case opened. Thanks Andreas. ------------------------------ Jose Ruiz ------------------------------
We have APAR IT46691: INTERACTIVE DBACCESS SURVIVING LOSS OF TERMINAL CONSUMING AN ENTIRE CPU https://www.ibm.com/support/pages/apar/IT46691?myns=swgother&mynp=OCSSGU8G&mync=E&cm_sp=swgother-_-OCSSGU8G-_-E ------------------------------ Jose Ruiz ------------------------------