《大型数据库系统分析与设计：Less05_Storage》由会员分享，可在线阅读，更多相关《大型数据库系统分析与设计：Less05_Storage（26页珍藏版）》请在金锄头文库上搜索。
1、5Copyright 2005, Oracle. All rights reserved.Managing Database Storage Structures5-2Copyright 2005, Oracle. All rights reserved.ObjectivesAfter 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 fil
2、esCreate and manage tablespacesObtain tablespace informationDescribe the main concepts and functionality of Automatic Storage Management (ASM)5-3Copyright 2005, Oracle. All rights reserved.Storage StructuresDatabaseTablespaceSegmentExtentOracle datablockLogicalPhysicalOSblockOS file5-4Copyright 2005
3、, Oracle. All rights reserved.How Table Data Is StoredTablespaceTable ATable BSegmentSegmentRowsColumnsTableBlocksRow pieceExtent5-5Copyright 2005, Oracle. All rights reserved.Anatomy of a Database BlockBlock headerFree spaceRow dataGrowth5-6Copyright 2005, Oracle. All rights reserved.Tablespaces an
4、d 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 databaseAre a repository
5、for schema object dataDatabaseTablespaceData files5-7Copyright 2005, Oracle. All rights reserved.Space 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 val
6、ue indicates free or used extents.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 compatibili
7、ty.5-8Copyright 2005, Oracle. All rights reserved.Creating a New Tablespace5-10Copyright 2005, Oracle. All rights reserved.Storage for Locally Managed Tablespaces5-12Copyright 2005, Oracle. All rights reserved.Tablespaces in the Preconfigured DatabaseSYSTEMSYSAUXTEMPUNDOTBS1USERSEXAMPLE5-14Copyright
8、 2005, Oracle. All rights reserved.Altering a Tablespace5-17Copyright 2005, Oracle. All rights reserved.Actions with Tablespaces5-19Copyright 2005, Oracle. All rights reserved.Dropping Tablespaces5-20Copyright 2005, Oracle. All rights reserved.Viewing Tablespace Information5-21Copyright 2005, Oracle
9、. All rights reserved.Where We AreUsing tablespaces to separate dataCreating various types of tablespacesManaging tablespacesObtaining tablespace informationDescribe the main concepts and functionality of Automatic Storage Management (ASM)5-22Copyright 2005, Oracle. All rights reserved.What Is Autom
10、atic Storage Management?Is a portable and high-performancecluster file systemManages Oracle database filesSpreads data across disksto balance loadMirrors dataSolves many storage management challengesASMFilesystemVolumemanagerApplicationDatabaseOperating system5-23Copyright 2005, Oracle. All rights r
11、eserved.ASM: 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 database filesIs cluster awareIs automatically installed5-24Copyr
12、ight 2005, Oracle. All rights reserved.ASM: ConceptsDatabaseTablespaceSegmentExtentOracle datablockData filePhysicalblockASM diskASM fileAllocation unitFile systemfileorRaw deviceASMdisk group5-25Copyright 2005, Oracle. All rights reserved.SummaryIn this lesson, you should have learned how to:Descri
13、be 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 rebalancingASM disk groups5-26Copyright 2005, Oracle. All rights reserved.Practice Overview:Managing Database Storage StructuresThis practice covers the following topics:Creating tablespacesGathering information about tablespaces
