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1、OracleArchitecturalComponentsCopyright©OracleCorporation,2002.Allrightsreserved.ObjectivesAftercompletingthislesson,youshouldbeabletodothefollowing:•OutlinetheOraclearchitectureanditsmaincomponents•ListthestructuresinvolvedinconnectingausertoanOraclei
2、nstance1-2Copyright©OracleCorporation,2002.Allrightsreserved.ObjectivesThislessonintroducestheOracleserverarchitecturebyexaminingthephysical,memory,process,andlogicalstructuresinvolvedinestablishingadatabaseconnection,creatingasession,andexecutingSQLc
3、ommands.Oracle9iDatabaseAdministrationFundamentalsI1-2OverviewofPrimaryComponentsInstanceUserprocessSharedPoolSGALibraryRedoLogDatabaseCacheBufferBufferCacheServerDataDictionaryprocessCacheJavaPoolLargePoolPGAPMONSMONDBWRLGWRCKPTOthersDataControlRedoL
4、ogParameterfilesfilesfilesArchivedfileLogfilesPasswordfileDatabase1-3Copyright©OracleCorporation,2002.Allrightsreserved.OverviewofPrimaryComponentsTheOraclearchitectureincludesanumberofprimarycomponents,whicharediscussedfurtherinthislesson.•Oracleserv
5、er:Thereareseveralfiles,processes,andmemorystructuresinanOracleserver;however,notallofthemareusedwhenprocessingaSQLstatement.Someareusedtoimprovetheperformanceofthedatabase,toensurethatthedatabasecanberecoveredintheeventofasoftwareorhardwareerror,orto
6、performothertasksnecessarytomaintainthedatabase.TheOracleserverconsistsofanOracleinstanceandanOracledatabase.•Oracleinstance:AnOracleinstanceisthecombinationofthebackgroundprocessesandmemorystructures.Theinstancemustbestartedtoaccessthedatainthedataba
7、se.Everytimeaninstanceisstarted,aSystemGlobalArea(SGA)isallocatedandOraclebackgroundprocessesarestarted.Backgroundprocessesperformfunctionsonbehalfoftheinvokingprocess.TheyconsolidatefunctionsthatwouldotherwisebehandledbymultipleOracleprogramsrunningf
8、oreachuser.Thebackgroundprocessesperforminput/output(I/O)andmonitorotherOracleprocessestoprovideincreasedparallelismforbetterperformanceandreliability.Oracle9iDatabaseAdministrationFundamentalsI1-3OverviewofPrimaryComponents(continued)•Oracled