While starting oracle database observed, PMON ospid: terminating the instance due to error 12752. SA00 died unexpectedly, VKTM detected a forward time drift.
Below are the complete alert log messages.
Warning: VKTM detected a forward time drift.
Time drifts can result in unexpected behavior such as time-outs.
Please see the VKTM trace file for more details:
/scratch/u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_vktm_61607.trc
2019-08-22T02:40:31.548649-07:00
Instance Critical Process (pid: 8, ospid: 61615, SA00) died unexpectedly
PMON (ospid: 61600): terminating the instance due to error 12752
2019-08-22T02:40:32.612079-07:00
Instance terminated by PMON, pid = 61600
Reason and resolution steps:
After investigation we observed that there was no free memory available for the database instance.
[root@orahow ~]# free -g
total used free shared buff/cache available
Mem: 14 13 0 0 0 0
Swap: 15 15 0
We rebooted the server to release the memory occupied by the process. After reboot there was free memory available for the database and the DB started normally. You can execute “echo 3 > /proc/sys/vm/drop_caches” command to release the memory. If its not working then reboot the server and start the database.
After reboot:
bash-4.2$ free -g
total used free shared buff/cache available
Mem: 14 3 8 0 1 10
Swap: 15 0 15
bash-4.2$ sqlplus / as sysdba
SQL*Plus: Release 12.2.0.1.0 Production on Thu Aug 22 03:17:47 2019
Copyright (c) 1982, 2016, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 4529848320 bytes
Fixed Size 8801680 bytes
Variable Size 989856368 bytes
Database Buffers 3523215360 bytes
Redo Buffers 7974912 bytes
Database mounted.
Database opened.