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12.2双机rac,VKTM时间drift漂移

原创 问题归档 2019-04-14
3944

问题描述

2019-03-25T08:00:01.412940+08:00

Warning: VKTM detected a time stall.

Time drifts can result in unexpected behavior such as time-outs.

Please see the VKTM trace file for more details:

/u01/app/oracle/diag/rdbms/db/db/trace/db_vktm_63714.trc


两节点ntp服务已关闭

# service ntpd status

ntpd is stopped


Trace file /u01/app/oracle/diag/rdbms/db/db/trace/db_vktm_63714.trc

Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production

Build label:    RDBMS_12.2.0.1.0_LINUX.X64_170125

ORACLE_HOME:    /u01/app/oracle/product/12.2.0/db1

System name: Linux

Node name: db1

Release: 2.6.32-573.el6.x86_64

Version: #1 SMP Thu Jul 23 15:44:03 UTC 2015

Machine: x86_64

Instance name: db12

Redo thread mounted by this instance: 0

Oracle process number: 6

Unix process pid: 63714, image: oracle@db12 (VKTM)



*** 2019-02-10T15:09:46.168294+08:00 (CDB$ROOT(1))

*** CLIENT ID:() 2019-02-10T15:09:46.168349+08:00

*** SERVICE NAME:() 2019-02-10T15:09:46.168357+08:00

*** MODULE NAME:() 2019-02-10T15:09:46.168363+08:00

*** ACTION NAME:() 2019-02-10T15:09:46.168372+08:00

*** CLIENT DRIVER:() 2019-02-10T15:09:46.168379+08:00


[kji_attach][LMON !running, !call kjual]

*** SESSION ID:(727.45771) 2019-02-10T15:09:46.172975+08:00

*** SERVICE NAME:() 2019-02-10T15:09:46.172994+08:00

*** CONTAINER ID:(1) 2019-02-10T15:09:46.173001+08:00


kstmmainvktm: succeeded in setting elevated priority

highres_enabled

VKTM running at (1)millisec precision with DBRM quantum (100)ms

[Start] HighResTick = 75394510316

kstmrmtickcnt = 0 : ksudbrmseccnt[0] = 1549782586

kstmchkdrift (kstmhighrestimecntkeeper:lowres): Time moved backward by (68)microsecs at 1550713032


*** 2019-02-21T09:36:10.411244+08:00 (CDB$ROOT(1))

kstmchkdrift (kstmhighrestimecntkeeper:lowres): Time moved backward by (62)microsecs at 1550713032

kstmchkdrift (kstmhighrestimecntkeeper:lowres): Time moved backward by (56)microsecs at 1550713032

kstmchkdrif


怎么解决?

专家解答

可以尝试调整该功能:

In general VKTM process need to be scheduled in every 10ms, if due to above reasons this is not happening, occurs less than 1sec and 5 sec then it is permissible.

Eventually, this probably would cause the resource manager to take improper decisions and can lead to a hang in worst case.

If the time drifts occurs less than 1sec and 5 sec for forward and backward respectively, then it is permissible and OK.

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

alter system set "_disable_highres_ticks"=true scope=spfile;

_timer_precision = 500

最后修改时间:2019-04-14 14:33:25
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