ORA-00800: soft external error, arguments: [Set Priority Failed], [VKTM]

We have had a few database upgraded from 12c/18c to 19c (running on Oracle Linux 7) recently and all of them have had this error during the startup of the database since the upgrade:

ORA-00800: soft external error, arguments: [Set Priority Failed], [VKTM], [Check traces and OS configuration], [Check Oracle document and MOS notes], []

VKTM stands for Virtual Keeper of Time Process , it provides a wall clock time and reference time for time interval measurements . it acts as a time publisher for the Oracle database instance.

Followed the MOS notes 2718971.1 & 2551359.1 and checked:

  1. The hidden parameter “_highest_priority_processes” is set to “VKTM”;
  2. “Sticky bit” is set for the file “$ORACLE_HOME/bin/oradism”;
  3. PMON & VKTM’s cpu cgroups are set correctly to “7:cpu,cpuacct:/“;
  4. VKTM process’ priority
SQL> select a.ksppinm "Parameter", b.ksppstvl "Session Value", 
c.ksppstvl "Instance Value", a.KSPPDESC "Describtion"
from x$ksppi a, x$ksppcv b, x$ksppsv c
where a.indx = b.indx and a.indx = c.indx and a.ksppinm like '_%' 
and a.ksppinm like '_highest_priority_process%';

Parameter                      Session Va Instance V Describtion
------------------------------ ---------- ---------- ----------------------------------------
_highest_priority_processes    VKTM       VKTM       Highest Priority Process Name Mask

[oracle@joetestDB 12c_archivelog]$ ls -lrt $ORACLE_HOME/bin/oradism
-rwsr-x---. 1 root oinstall 147848 Apr 17  2019 /opt/oracle/190000/bin/oradism

[oracle@joetestDB 12c_archivelog]$ ps -eaf|grep -i pmon|grep -v grep
oracle   22194     1  0 Dec21 ?        00:00:37 ora_pmon_APROD
[oracle@joetestDB 12c_archivelog]$ cat /proc/22194/cgroup |grep cpu
7:cpu,cpuacct:/
3:cpuset:/
[oracle@joetestDB 12c_archivelog]$ ps -eaf|grep -i vktm |grep -v grep
oracle   22201     1  0 Dec21 ?        00:02:11 ora_vktm_APROD
[oracle@joetestDB 12c_archivelog]$ cat /proc/22201/cgroup |grep cpu
7:cpu,cpuacct:/
3:cpuset:/

[oracle@joetestDB 12c_archivelog]$ ps -A -o pid,tid,pri | grep 22201
22201 22201  19

Other than the priority of VKTM is 19 instead of 39 mentioned in the note 2551359.1, rest of results from other 3 checks seems to be fine. Fortunately we haven’t seen any impact yet, Oracle has been running fine on 19c after the upgrade in spite of the ORA-00800 error during the startup.

From the notes 2627545.1, it sounds like Oracle is investigating it as the bug 31592108. It’s interesting that we haven’t seen this error on a fresh installation of 19c database.

References:

  • ORA-00800: soft external error, arguments: [Set Priority Failed], [VKTM], for Oracle Linux (Doc ID 2718971.1)
  • ORA-00800: Soft External Error, Arguments: [Set Priority Failed], [VKTM] [Check traces and OS configuration] (Doc ID 2551359.1)
  • Get ORA-800 Errors After Restart The Instance(Doc ID 2627545.1)

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