吉林大学大型数据库设计与实现dba-01.PPT
OracleArchitecturalComponents吉林大学
ObjectivesAftercompletingthislesson,youshouldbeabletodothefollowing:OutlinetheOraclearchitectureanditsmaincomponentsListthestructuresinvolvedinconnectingausertoanOracleinstance
OverviewofPrimaryComponentsInstanceSGARedolog
buffercacheSharedpoolDataDict.
cacheLibrarycacheDBWRSMONPMONCKPTLGWROthersUser
processServer
processPGAControlfilesDatafilesArchivedlogfilesParameterfilePasswordfileRedologfilesDatabaseDatabase
buffercache
OracleServerAnOracleserver:Isadatabasemanagementsystemthatprovidesanopen,comprehensive,integratedapproachtoinformationmanagementConsistsofanOracleinstanceandanOracledatabaseOracleServer
OracleInstanceAnOracleinstance:IsameanstoaccessanOracledatabaseAlwaysopensoneandonlyonedatabaseConsistsofmemoryandprocessstructuresBackgroundstructuresMemorystructuresSGARedolog
buffercacheDatabase
buffercacheSharedpoolDBWRSMONPMONCKPTLGWROthersDataDictionary
cacheLibrarycacheInstance
EstablishingaConnection
andCreatingaSessionConnectingtoanOracleinstanceconsistsofestablishingauserconnectionandcreatingasession.ConnectionestablishedSessioncreatedDatabaseuserUser
processOracleserverServer
process
OracleDatabaseAnOracledatabase:IsacollectionofdatathatistreatedasaunitConsistsofthreefiletypesControlfilesDatafilesArchivedlogfilesParameterfilePasswordfileRedologfilesOracleDatabase
PhysicalStructure
ThephysicalstructureofanOracledatabaseisdeterminedbytheoperatingsystemfilesthatprovidetheactualphysicalstoragefordatabaseinformation.ControlfilesDatafilesRedologfilesControlfilesDatafiles(includesdatadictionary)HeaderOnlineredologfiles)
MemoryStructureOracle’smemorystructureconsistsoftwomemoryareasknownas:SystemGlobalArea(SGA):Allocatedatinstancestartup,andisafundamentalcomponentofanOracleInstanceProgramGlobalArea(PGA):Allocatedwhenthes