7/31/2019 Ora_chintu - Notepad

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ora_chintu-- The oracle Database

> Memory Areas> processes> Data Files> Development Tools> Applications

> Queary Tools

--Memory Area(Shared Memory Structure)SGA

> Database Buffer Cache> Shared Pool

Instances in oracle = set of memory structure + background process that accessset of data files.

it is possible for a single database to beaccessed by multipleinstances.( parallel server option)

Oracle processes ( four main catagories)> servicing the user request> writing data to data file> recording transaction to log file> monitoring the funtioning of the database

Oracle Process Architecture

Required process ( main process)PMON SMON DBWR LGWR

Optional ProcessLCK ( Locker Writer) CKPT ( Check Point Process) WMON ( Weakup

monitor)snmpn( Snapshot process) - it is a replication facility to copy

data changes from one database to anotherDnnn ( Dispatcher) each dispatcher handles requests of several

userServer Process

Dedicated server processDispatched DnnShared server process SnnListener

PMON SMONMemoryArea

DBW LGWR

| |Data File Log Files

--SMON> Caretaker of the instance> Detects Deadlock> Temporary segment Release> Free Space fragments> performe recovery

--PMON> Care tacker of the processes> monitor externals

( PMON automatically roll back the workof the user processes since thetrasaction started,

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ora_chintuit releases any locks and other system resources taken up by the

failed process)--DBWR

> Transfer Data to physicaldisk> Manages free buffers

--LGWR

> Record to Transaction log

Optional process

--ARCH ( archive log mode)> Archive is started by Log writer

- when database is operated in archive log mode- when then LGWR finishes filling up one of the online redolog

file to either a new file on a diskdrive or toa tape

--RECO (Recoverer)LCK ( Locker Writer) CKPT ( Check Point Process) WMON ( Weakup monitor)

snmpn( Snapshot process) - it is a replication facility to copydata changes

from one database to another

Dnnn ( Dispatcher) each dispatcher handles requests of severaluser

Server Process

--Dedicated server process> All user get dedicated server process when they connect to the oracle

instance and remain until theydisconnect from the database

> it is a interface between a user process sending request to thedatabase and memory area and files

--Listener - it is a process monitor that is defined communication channel.waiting for a request from the client.

User server processes> oracle server code that translates and execute SQL

MEMORY AREA of Oracle> Software Code Area> SGA> PGA> Sort Areas

STORAGE (files) of Oracle data files

> Data files> online Redolog files> Archive log files> Initialization files> Control Files> SGA defination files> Oracle processing log and error ( trace) file

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