Oracle学习笔记<<3>>

Oralce Architectural Components

Process Structure

Oracle takes advantage of various types of processes:

User Process

负责和客户端连接，并返回执行结果。有两种模式分为dedicated 和shared server模式

Background Process

Maintains and enforces relationships between physical and memory starututes:

DBWn???? PMON??? CKPT??? LGWR? SMON

ARCn????? LMDn??? QMNn??? CJQ0?? LMON

RECO????? Dnnn???? LMS????? Snnn?? LCKn?? Pnnn

Database Writer (DBWn)

DBWn writes when :

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DBWn 中的n 有20个 从DBW0到DBW9, 从DBWa 到DBWg

Log Writer(LGWR)

LGWR writes:

System Monitor

Responsibilities:

Rolls forward changes in online redo log files

Opens database for user access

?????? ?????? Rolls back uncommitted transactions

Process Monitor

Cleans up after failed processes by :

Checkpoint(CKPT)

Responsible for:

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Archiver(ARCn)

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