Re: VKTM background process terminating the DB instance.

Hi Nenad,

Sorry there was typo below. Below is the correct VKTM trace file. And yes you are right there is ORA-07445 reported. But not sure why we are not getting this issue for the DB instances after we moved to a different host.

kstmmainvktm: succeeded in setting elevated priority Verify: SETUID is set on ORADISM and restart the instance highres_enabled

• 2021-08-11 01:31:04.534 VKTM running at (1)millisec precision with DBRM quantum (100)ms [Start] HighResTick = 35067506276 kstmrmtickcnt = 0 : ksudbrmseccnt[0] = 1628645464
• 2021-08-11 04:36:31.842 Exception [type: SIGSEGV, Address not mapped to object] [ADDR:0x7F03344687D0] [PC:0x7F03344687D0, {empty}] [flags: 0x0, count: 1] Incident 1800033 created, dump file: /n02/base/diag/rdbms/xxxx/xxxxx/incident/incdir_1800033/xxxx_vktm_14386_i1800033.trc ORA-07445: exception encountered: core dump [PC:0x7F03344687D0] [SIGSEGV] [ADDR:0x7F03344687D0] [PC:0x7F03344687D0] [Address not mapped to object] []

ssexhd: crashing the process...
Background_Core_Dump = partial

Thanks,
Goti

On Wed, Aug 11, 2021 at 1:56 PM Goti <aryan.goti_at_gmail.com> wrote:

> Hi Nenad,
>
> Thanks for responding.
>
> Below is the VKTM trace. BTW forgot to mention that, we moved a couple of
> DB instances to another host post which those DB instances are not getting
> terminated.
>
> VKTM Trace:
>
> kstmmainvktm: succeeded in setting elevated priority
> Verify: SETUID is set on ORADISM and restart the instance
> highres_enabled
>
> *** 2021-08-11 04:36:49.798
> VKTM running at (1)millisec precision with DBRM quantum (100)ms
> [Start] HighResTick = 46212770348
> kstmrmtickcnt = 0 : ksudbrmseccnt[0] = 1628656609
>
> Thanks,
> Goti
>
>
> On Wed, Aug 11, 2021 at 1:51 PM Noveljic Nenad <
> nenad.noveljic_at_vontobel.com> wrote:
>
>> Strace shows the segmentation fault (sigsegv) which normally translates
>> to ora-7445.
>>
>> What are the last entries in the vktm trace?
>>
>>
>>
>> *Von: *oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org> im
>> namen von: Goti <aryan.goti_at_gmail.com>
>> *Datum *Mittwoch, 11. Aug. 2021, 8:54 AM
>> *An: *ORACLE-L <oracle-l_at_freelists.org>
>> *Betreff: *VKTM background process terminating the DB instance.
>>
>> Hi All,
>>
>> Envt Details: DB version 12.1.0.2 Apr 2019 PSU , Running on VM RHEL 7.7
>>
>> We have an issue wherein we have 6 DB instances running on different VM's
>> sharing the same host getting terminated. The background process VKTM dies
>> and subsequently PMON terminates the instance. Raised an SR with Oracle a
>> couple of weeks back but so far they have not been able to find the root
>> cause.Also i did follow some of the recommendations given the below MOS
>> notes, but that also didn't help. Prior to VKTM getting terminated , the
>> strace just shows "nanosleep({0, 1000000}, 0x7fff29abd7f0) = 0" in its
>> trace file. Please find the below gist file which contains strace
>> information of VKTM process just before it got terminated.
>>
>> https://gist.github.com/aryangoti/7fd0882352e4d6e306d212ff1ab0a432
>>
>> MOS Notes:
>> ==============
>> Customer RecommendedVKTM processes consume High CPU (Doc ID 1992652.1)
>>
>> Patch For Excessive VKTM And VKRM Traces In Bug 9382956 Requires Events
>> (Doc ID 1381270.1)
>>
>> Alert log snippet:
>> ========================
>> Wed Aug 11 01:30:55 2021
>> Instance Critical Process (pid: 4, ospid: 8566, VKTM) died unexpectedly
>> PMON (ospid: 8561): terminating the instance due to error 56703
>> Wed Aug 11 01:30:55 2021
>> System state dump requested by (instance=1, osid=8561 (PMON)),
>> summary=[abnormal instance termination].
>> System State dumped to trace file
>> /xxx/xxxxx/diag/rdbms/xxxx/xxxxx/trace/xxxx_diag_8576_20210811013055.trc
>> Wed Aug 11 01:30:56 2021
>> Dumping diagnostic data in directory=[cdmp_20210811013055], requested by
>> (instance=1, osid=8561 (PMON)), summary=[abnormal instance termination].
>> Wed Aug 11 01:30:57 2021
>> Instance terminated by PMON, pid = 8561
>> ==============================================================
>>
>>
>> Appreciate of i can get some help here!
>>
>>
>> Thanks,
>> Goti
>>
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