RE: VKTM ? Anyone?

Hi Marco,  

If the xml loading process managed to use up all free memory in the system
(and eventually failed with ORA-4030) then other processes can't do further
allocations either. VKTM might have been the unlucky victim in this case.  

I consider setting some sort of virtual memory limit with ulimit a good practice. I normally set it some 10x higher amount than I think the process ever needs (so that processes wouldn't fail due occasional spikes in memory usage), but rogue processes and memory leaks will not be able to eat up all memory.  

On which OS, platform and version you are?  

Linux kernel allows virtual memory overallocation ( if /proc/sys/vm/overcommit_memory > 0 ), but in that case it starts killing processes if it runs out of memory when processes start touching those allocated pages. If the memory overcommit is enabled, then again VKTM might have been unlucky victim again. Syslog should have some lines about it in such case i think...    

Anyway, if the root cause for the issues wasn't memory overallocation but just VKTM crashing, there's a _disable_vktm parameter you can ask support about ;-)  

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Tanel Poder
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From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of Marco Gralike
Sent: Tuesday, September 16, 2008 15:59
To: oracle-l_at_freelists.org
Subject: VKTM ? Anyone?


Apparently I missed something somewhere... 
 
Errors in file /oracle/diag/rdbms/test/TEST/trace/TEST_pmon_16980.trc:
ORA-56703: VKTM process died unexpectedly
Mon Sep 15 22:16:47 2008
Error occured while spawning process q001; error = 56703
PMON (ospid: 16980): terminating the instance due to error 56703
Mon Sep 15 22:16:53 2008
Termination issued to instance processes. Waiting for the processes to exit
Instance termination failed to kill one or more processes
Mon Sep 15 22:17:15 2008
Instance terminated by PMON, pid = 16980

 
[oracle_at_srv trace]$ oerr ora 56703

56703, 00000, "VKTM process died unexpectedly"
// *Cause: An explicit kill or internal error caused the death of VKTM
//         background process.
// *Action: Restart the instance.

Apparently that this is serious enough, my instance crashed and to my
surprise without something like a ORA-0600 (maybe because "it is
handled..."), although I can imagine that this process, apparently with
dependencies with PMON, will cause the other important backgound processes
to shut down (if not already the case). 
 
For those who are interested this happened after trying to insert a lot off
big xml files into a binary xml xmltype, table which caused a lot of
ORA-04030, that caused job queue processes to die, that caused server


(shared server) processes to die, that signaled pmon to terminate the

instance.
 
 
So my question...
 

Does anyone know what a "VKTM" background process is...?


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