1. M ODULE 3: W EEK 6 D ATABASE MANAGEMENT 1 ITEC 450 Fall 2012

2. A CCESS D ATABASE – SQL P LUS Fall 2012 2 ITEC 450

3. SQL P LUS L OGIN Fall 2012 3 ITEC 450

4. SQL P LUS C OMMANDS Fall 2012 4 ITEC 450

5. OEM ( HTTPS ://{ HOSTNAME }:1158/ EM ) Fall 2012 5 ITEC 450

6. T HE D ATA D ICTIONARY Looking at Data Dictionary Components Using Data Dictionary Views Useful Dynamic Performance Views Examining Table Structure Using SQL*Plus and iSQL*Plus Fall 2012 6 ITEC 450

7. LOOKING AT DATA DICTIONARY Fall 2012 7 ITEC 450

8. LOOKING AT DATA DICTIONARY Generally, USER, ALL, and DBA views are in sets USER_TABLES, ALL_TABLES, DBA_TABLES Each view has nearly identical columns USER version omits OWNER column; it also sometimes omits columns to simplify the view V$ and GV$ views are in sets There are few views that don’t begin these prefixes For simplicity, all views (except DBA ones) prefix public synonyms and public permission to query Fall 2012 8 ITEC 450

9. U SING D ATA D ICTIONARY V IEWS Frequently used (static) data dictionary views: USER_TABLES, USER_VIEWS ALL_DEPENDENCIES USER_ERRORS USER_INDEXES, USER_IND_COLUMNS DBA_SOURCE USER_TAB_PRIVS, ALL_TAB_PRIVS_MADE USER_TAB_PRIVS_MADE DBA_USERS PRODUCT_COMOPONET_VERSION Fall 2012 9 ITEC 450

10. U SEFUL D YNAMIC P ERFORMANCE V IEWS Begin with V$ and have a counterpart GV$ view V$SYSSTAT V$SQL V$SESSTAT V$SESSION_WAIT V$FILESTAT Primary use: tuning the database system Oracle provides options for gathering/viewing stats Statistics are used to tune a database This book does not cover the details of DB tuning Fall 2012 10 ITEC 450

11. M ODULE 3 D ATABASE M ANAGEMENT Section 1 Database Change Management 11 ITEC 450 Fall 2012

12. D RIVERS FOR C HANGE M ANAGEMENT Change is inevitable but necessary for business survival and success. Missed a requirement – an existing system is missing a feature Identified a defect Scalability demand, marketplace changes Policy and politics – process, procedure or methodology; legislation changes Fall 2012 12 ITEC 450

13. C HANGE M ANAGEMENT R EQUIREMENTS Proactively change – the earlier to make change, the lower cost to achieve it Planning analysis – intelligently examining the change whether it is necessary, and planning to do it right the first time Impact analysis – comprehensive impact and risk analysis Execution – standardization of procedure, availability consideration, quick and efficient delivery Fall 2012 13 ITEC 450

14. T YPES OF D ATABASE C HANGES DBMS software – versions and releases for new features, functions, bug fixes, support models Hardware configuration – memory, CPU, storage device Logical and physical design for an application Physical database structures Fall 2012 14 ITEC 450

15. I MPACT OF D ATABASE C HANGES Data Definition Language is mainly used for database changes. Create, alter, and drop schema objects require exclusive access to the specified object The change is implicitly committed The change may cause dependent objects become invalid, which may need to recompile or reauthorize schema objects Recovery from a database change is challenging, and has to be well-planned. Fall 2012 15 ITEC 450

16. E XECUTION OF D ATABASE C HANGES Maintain current database structures – source control and version control Migration process Request database change Standardized change requests Managing database changes from one database environment to another Condense a series of changes by comparing database structures, and migrate the differences Fall 2012 16 ITEC 450

17. E XAMPLES OF D ATABASE C HANGES Change Management: planning (necessary?) impacts, and execution (recovery?) Add a new column to the end of a table Resize a column from char (8) to char (12) Re-create a new package, procedure, or function Add a new column to the middle of a table Fall 2012 17 ITEC 450

18. M ODULE 3 D ATABASE M ANAGEMENT Section 2 High Availability Requirement and Architecture 18 ITEC 450 Fall 2012

19. D RIVERS OF A VAILABILITY Availability is the condition where a given resource can be accessed by its consumers. Mandate for 24x7 availability Shrinking maintenance window Full-time availability: airline reservation systems, credit card approval Cost of downtime Fall 2012 19 ITEC 450

20. A VAILABILITY P ROBLEMS Disasters: loss of the data center System failures Server infrastructure problems: network, loss of the server hardware, storage, operating system Software failure: DBMS, application, corruption of data Data failures Procedure problems: security and authorization, loss of database objects Human errors: loss of data, DBA mistakes Fall 2012 20 ITEC 450

21. A VAILABILITY S OLUTIONS Automate DBA functions Exploit high-availability DBMS features Exploit clustering technology Hardware redundancy design Fall 2012 21 ITEC 450

22. H IGH A VAILABILITY DBMS F EATURES Solutions to disasters Oracle data guard – a single primary database and one or more standby database SQL Server database mirroring – a single copy of the mirrored database that must reside on a different server instance, usually on a separate physical server in a different location Hardware replication: EMC SRDF Solutions to system failures Oracle Real Application Clusters SQL Server transactional replication DB2 Data Sharing Solutions to data failures Backup and recovery capability Flashback database: view data at a point-in-time in the past Partition: decompose large tables and indexes into smaller and more manageable pieces Fall 2012 22 ITEC 450

23. C LUSTERING T ECHNOLOGY A cluster is a group of interconnected servers for increasing the reliability of servers. Oracle standby database: Fall 2012 23 ITEC 450

24. ORACLE REPLICATION Fall 2012 24 ITEC 450

25. SQL S ERVER D ATABASE M IRRORING Database mirroring maintains an exact copy of the database on the mirror. It works at the level of the physical log record (by sending the actual log records to the mirror server). Fall 2012 25 ITEC 450

26. SQL S ERVER T RANSACTIONAL R EPLICATION A RCHITECTURE Fall 2012 26 ITEC 450

27. O RACLE R EAL A PPLICATION C LUSTER (RAC) Oracle database with RAC architecture build higher levels of availability on top of the standard Oracle features. Fall 2012 27 ITEC 450

28. H ARDWARE R EDUNDANCY D ESIGN No single point of failures on CPU, Memory, I/O controller, Network, etc. Clustered software to failover to another server in seconds RAID technology (Redundant Arrays of Inexpensive Disks) – one large logical storage unit with a set of physical disk drives Fall 2012 28 ITEC 450

29. RAID T ECHNOLOGY RAID example with 4 disks and striping. Pages 1-4 can be read/written simultaneously Fall 2012 29 ITEC 450

30. W RAP U P Assignment 6-1: Research Paper: Database High Availability Fall 2012 30 ITEC 450