In this Document

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.2 and later
Information in this document applies to any platform.

Goal

Below message keeps repeating in Alert-log.

Time drift detected. Please check VKTM trace file for more details.

This note explains the possible cause and if the issue needs to be addressed or not.

Fix

There are multiple bugs filed for this issue, Some of them follows:

Bug 12601857 - TIME DRIFT DETECTED. PLEASE CHECK VKTM TRACE FILE FOR MORE DETAILS.
Bug 12374867 - TIME DRIFT DETECTED. PLEASE CHECK VKTM TRACE FILE FOR MORE DETAILS.

Which were closed as duplicates of:

Bug 11837095 "TIME DRIFT DETECTED" APPEARS INTERMITTENTLY IN ALERT LOG, THO' EVENT 10795 SET.

To fix the issue, please download and apply patch 11837095 as available for your release/platform.

NOTE:
Patch 11837095 extends to functionality of event 10795 (set to level 2) for VKTM tracing and limits alert log entries.

After applying the patch, enable event 10975 at level 2:

alter system set event="10795 trace name context forever, level 2" scope=spfile;

 Then bounce the instance (shutdonw then startup) for the event to be applied.

The permanent fix is planned to be included in the 11.2.0.4 and 12.1 releases.

Meaning and technical Impact of the error:

The time drifts usually occurring less than 1sec and 5 sec for forward and backward respectively are permissible and OK.
If the traces are emitting time drifts of amount beyond these ranges, then it needs to be analyzed.
Most of the times, during high loads, there would be issues with underlying OS due to virtual memory, network time protocol improper configuration etc.

In general VKTM process need to be scheduled in every 10ms, if due to above reasons this is not happening we see the time drifts and to certain level (mentioned above) are permissible.
Eventually, this probably would cause the resource manager to take improper decisions and can lead to a hang in worst case.

VKTM process trace file can be found under bdump, However in this case the trace file doesn't contain useful information, Which makes the message ambiguous.

References

BUG:11837095 - "TIME DRIFT DETECTED" APPEARS INTERMITTENTLY IN ALERT LOG, THO' EVENT 10795 SET
BUG:12374867 - TIME DRIFT DETECTED. PLEASE CHECK VKTM TRACE FILE FOR MORE DETAILS
NOTE:1381270.1 - Patch For Excessive VKTM And VKRM Traces In Bug 9382956 Requires Events
NOTE:1055257.1 - Starting a Database Using Solaris Zone Generates Errors in the vktm Trace File
NOTE:837105.1 - The Database Server Is Creating A Lot Of Trace Files From the VKTM Process
NOTE:822635.1 - Ksesethighpri: (Ksb.C:3539) Failed to Elevate VKTM's Priority Found In Trace Files
BUG:12601857 - TIME DRIFT DETECTED. PLEASE CHECK VKTM TRACE FILE FOR MORE DETAILS.
NOTE:1185093.1 - VKTM Trace Files Generated With KSTMCHKDRIFT "BACKWARD DRIFT ENDED AT"