Oracle VKRM 後臺程式介紹

有好幾次重啟 Oracle 11g 資料庫，在告警日誌中，都會發現在資料庫關閉和開啟的最後一步，都會出現 VKRM 這個後臺程式，於是就去文件中查了一下這個程式的說明。

alert 中關閉資料庫的記錄

ARC1: Archival stopped
Thread 1 closed at log sequence 14797
Successful close of redo thread 1
Mon Dec 21 21:59:03 2015
Completed: ALTER DATABASE CLOSE NORMAL
ALTER DATABASE DISMOUNT
Shutting down archive processes
Archiving is disabled
Completed: ALTER DATABASE DISMOUNT
ARCH: Archival disabled due to shutdown: 1089
Shutting down archive processes
Archiving is disabled
ARCH: Archival disabled due to shutdown: 1089
Shutting down archive processes
Archiving is disabled
Mon Dec 21 21:59:04 2015
Stopping background process VKTM
Mon Dec 21 21:59:24 2015
Instance shutdown complete

alert 中啟動資料庫的記錄

Starting background process CJQ0
Mon Dec 21 22:13:01 2015
CJQ0 started with pid=59, OS id=8663
Setting Resource Manager plan SCHEDULER[0x3189]:DEFAULT_MAINTENANCE_PLAN via scheduler window
Setting Resource Manager plan DEFAULT_MAINTENANCE_PLAN via parameter
Mon Dec 21 22:13:05 2015
Starting background process VKRM
Mon Dec 21 22:13:05 2015
VKRM started with pid=73, OS id=8711

官方文件中的說明如下：

VKRM

Virtual Scheduler for Resource Manager Process

Serves as centralized scheduler for Resource Manager activity

VKRM manages the CPU scheduling for all managed Oracle processes. The process schedules managed processes in accordance with an active resource plan.

Database instance

這個程式主要負責 Resource Manager ，配合資源計劃，為 Oracle所有的程式分配 CPU 資源。