SMSE05数据字典与实例优化.pptVIP

Data Dictionary Contents and Usage Objectives Identify key data dictionary components Identify the contents and uses of the data dictionary Describe the statistics kept in the dynamic performance views Developing for performance Oracle Instance Tuning Measure and tune the SGA(library cache hit ratio, dictionary cache hit ratio, data buffer,…) Identify the performance bottleneck(s): Oracle’s Wait Events” and OS statistics Tuning Goals and Techniques Query the data dictionary Create a Database Creating and starting oracle instance Creating database files Creating data dictionary views Adding PL/SQL support Adding advanced replication Adding oracle Jserver Adding oracle InterMedia Adding oracle spatial Adding oracle TimeSeries Adding oracle visual information retrieval Adding SQL*Plus help Database creation complete Data Dictionary Data dictionary tables: Dynamic performance tables PL/SQL packages were also created as well as Database event triggers. Characteristics of the Data Dictionary Central to every Oracle Database Describes the database and its objects Contains read-only tables and views Maintained by the Oracle server Accessed with SELECT Stored in the SYSTEM tablespace Owned by the user SYS Data Dictionary Includes two types of objects(two levels): Base tables(Internal level) Store description of database Created with CREATE DATABASE(sql.bsq) You should never attempt to write to these tables – never use DML commands to attempt to update base tables directly(IND$) Data Dictionary views(external level) Summarize base table information in order to make the information easier for a DBA to use. Created using catalog.sql script 数据字典中的数据按其易变程度分为： 来自基表、视图和索引的定义:元数据 来自数据库状态的定义：统计数据(ANALYZE) Data Dictionary Contents The data dictionary provides information about: Logical and physical database structure Definitions and space allocations of objects Integrity constraints Default values for columns Oracle user names (accounts) Roles Privileges Auditing in