ora_chintu - notepad
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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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7/31/2019 Ora_chintu - Notepad
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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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