1、Managing Database Storage StructuresObjectivesAfter completing this lesson, you should be able to do the following:Describe how table row data is stored in blocksDefine the purpose of tablespaces and data filesCreate and manage tablespacesObtain tablespace informationDescribe the main concepts and f

2、unctionality of Automatic Storage Management (ASM)Storage StructuresDatabaseTablespaceSegmentExtentOracle datablockLogicalPhysicalOSblockOS fileHow Table Data Is StoredTablespaceTable ATable BSegmentSegmentRowsColumnsTableBlocksRow pieceExtentAnatomy of a Database BlockBlock headerFree spaceRow data

3、GrowthTablespaces and Data FilesThe Oracle database stores data logically in tablespaces and physically in data files.Tablespaces:Can belong to only one databaseConsist of one or more data filesAre further divided into logical units of storageData files:Can belong to only onetablespace and one datab

4、aseAre a repository for schema object dataDatabaseTablespaceData filesSpace Management in TablespacesLocally managed tablespace:Free extents are managed in the tablespace.A bitmap is used to record free extents.Each bit corresponds to a block or group of blocks.The bit value indicates free or used e

5、xtents.The use of locally managed tablespaces is recommended.Dictionary-managed tablespace:Free extents are managed by the data dictionary.Appropriate tables are updated when extents are allocated or unallocated.These tablespaces are supported only for backward compatibility.Creating a New Tablespac

6、eCreating a New Tablespace(Notes Only Slide)Storage for Locally Managed TablespacesStorage for Locally Managed Tablespaces Full Notes PageTablespaces in the Preconfigured DatabaseSYSTEMSYSAUXTEMPUNDOTBS1USERSEXAMPLETablespaces in the Preconfigured Database Full Notes PageAltering a TablespaceAlterin

7、g a Tablespace Full Notes PageAltering a Tablespace Full Notes PageActions with TablespacesActions with TablespacesFull Notes PageDropping TablespacesViewing Tablespace InformationWhere We AreUsing tablespaces to separate dataCreating various types of tablespacesManaging tablespacesObtaining tablesp

8、ace informationDescribe the main concepts and functionality of Automatic Storage Management (ASM)What Is Automatic Storage Management?Is a portable and high-performancecluster file systemManages Oracle database filesSpreads data across disksto balance loadMirrors dataSolves many storage management c

9、hallengesASMFilesystemVolumemanagerApplicationDatabaseOperating systemASM: Key Features and BenefitsStripes files, but not logical volumesProvides online disk reconfiguration and dynamic rebalancingAllows for adjustable rebalancing speedProvides redundancy on a per-file basisSupports only Oracle dat

10、abase filesIs cluster awareIs automatically installedASM: ConceptsDatabaseTablespaceSegmentExtentOracle datablockData filePhysicalblockASM diskASM fileAllocation unitFile systemfileorRaw deviceASMdisk groupSummaryIn this lesson, you should have learned how to:Describe how table row data is stored in blocksDefine the purpose of tablespaces and data filesCreate and manage tablespacesObtain tablespace informationDescribe the main concepts and functionality of ASM, such as:Disk mirroringDynamic rebalancingAS