1. I NTRODUCTION OF W EEK 2  Assignment Discussion  Due this week:  1-1 (Exam Proctor): everyone including in TLC  1-2 (SQL Review): review SQL  Review of previous week and module  Concept: database, DBMS, SQL  DBA tasks: install software, create db, manage db, etc.  Oracle: types of database users, DBA security and privilege - sys and system  Overview of this week  DBMS architecture  Oracle architecture 1 ITEC 450 2011 Fall

2. S ECTION 2 DBMS S TRATEGY AND A RCHITECTURE Module 1 Database Administration Techniques and Practices 2 ITEC 450 2011 Fall

3. O RGANIZATION ’ S DBMS S TRATEGY It’s typical to run two or more DBMS products in large and medium-sized organization The organization should have the vision to consolidate and minimize the number Using an existing DBMS whenever it is possible Once a DBMS is installed, removal can be difficult: incompatibilities, conversion, special features Organization’s DBMS strategy is a join effort from groups of DBA, Architect, App Dev, and Business 3 ITEC 450 2011 Fall

4. C HOOSING A DBMS: S ELECTION D RIVERS A commercial off-the-shelf application package: ERM, PeopleSoft, CRM The latest and greatest technology: Web, Java,.NET DBMS performance: TPC benchmarks Operating systems: Unix, Windows, Linux Hardware platforms: HP, Sun, IBM, Dell Total cost of ownership : license, people, development, and maintenance support 4 ITEC 450 2011 Fall

5. L EVELS OF DBMS A RCHITECTURE Enterprise and Departmental DBMS Scalability and availability, high performance Large database, concurrent users, multiprocessors Examples: Oracle, DB2, SQL Server Personal DBMS: Access, Visual dBase, Personal Oracle Mobile DBMS: a special version of DBMS for remote users who are not on the network all the time. 5 ITEC 450 2011 Fall

6. DBMS A RCHITECTURE C OMPONENTS Disk: logical and physical database structures CPU: Operating system processes Memory: shared and private memory structures Network: user access and process interactions Clustering: multiple computing systems working together 6 ITEC 450 2011 Fall

7. S ECTION 3 O RACLE A RCHITECTURE Module 1 Database Administration Techniques and Practices 7 ITEC 450 2011 Fall

8. S ECTION I MPORTANT N OTES This section is Oracle specific. Terms can be very different among different DBMS’s (e.g. Oracle vs. SQL) Database (different) Instances (different) Schemas (common) Segments (Oracle specific) 8 ITEC 450 2011 Fall

9. O RACLE D ATABASE AND I NSTANCE An Oracle Database server consists of an Oracle Database and one or more Oracle Database instances. Database: all Oracle related files Data files – holding tables and indexes System files – System, Undo, Temp Physical and logical structures Instance: the combination of processes and memory Processes – background Memory – allocated to Oracle Running components – Instance is up 9 ITEC 450 2011 Fall

10. P HYSICAL D ATABASE S TRUCTURE Main types of files – data files, control files, redo log files, archived redo log files. Data files – database data, such as tables and indexes Control files – Oracle structure information, such as database name, data file names, time stamp of database Redo log files – database change logs for recovery Archived redo log files – offline copies of online redo log files Parameter files – SPFILE, init.ora Administration files – alert.log, trace files, the password files 10 ITEC 450 2011 Fall

11. L OGICAL D ATABASE S TRUCTURE Logical database structure consists of: tablespaces, segments, extents, and data blocks. A database is divided into one or more tablespaces. A tablespace contains one or more segments (such as tables, indexes). A segment is a logical structure with a set of extents. An extent is a specific number of contiguous data blocks. A data block is the smallest Oracle I/O unit. 11 ITEC 450 2011 Fall

12. L OGICAL S TRUCTURE D ETAILS Read Chapter 2 Oracle Database Concept Data block - the standard block size is determined by the init parameter DB_BLOCK_SIZE. Extent - When you create a database object, you allocate it an initial extent. When the object grows more than the initial extent, Oracle will automatically allocate next extent. Segment - Oracle calls all the space allocated to a particular database object a segment, such as table or index. Tablespace - A tablespace contains one or more physical files; a data file belongs to one and only one tablespace. 12 ITEC 450 2011 Fall

13. O VERVIEW OF O RACLE I NSTANCE When a database is started, Oracle starts many background processes and acquires memory structures. The combination of the background processes and memory buffers is called an Oracle instance. 13 ITEC 450 2011 Fall

14. O RACLE P ROCESSES Read Chapter 9 Oracle Database Concept A process is a connection or thread to the operating system. Oracle processes – server processes and background processes. The background processes are the core of the Oracle instance. When you start an instance, these processes are created; when you shutdown an instance, these processes are terminated. Database writer Log writer Process monitor System monitor User processes – connecting users to the database instance 14 ITEC 450 2011 Fall

15. O RACLE M EMORY S TRUCTURES Read Chapter 8 Oracle Database Concept The memory structures enable Oracle to share executable code, and produces high performance. Oracle uses two basic memory structures: shared and process-specific System global area (SGA) – total memory shared by all server processes including background processes Program global area (PGA) – memory used for private (application, program) processes 15 ITEC 450 2011 Fall

16. S YSTEM G LOBAL A REA The SGA main components. Database buffer cache – recently used blocks of data Shared pool – library cache, data dictionary cache Redo log buffer – a log of database changes Other Memory areas: Large pool – optional large memory segments for shared SQL and better performance Java pool – memory for java code and data within the JVM Streams pool – memory for using Streams Automatic shared memory management: total amount of SGA memory for the database 16 ITEC 450 2011 Fall

17. W RAP U P Assignment 2-1: Installation of Virtual Environment Assignment 2-2: DBA Roles and Expectations Please start to work on them right way. Course DVD Download information is on Bulletin Board. 17 ITEC 450 2011 Fall