RDBMS

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RDBMS

  1. 1. Outline Introduction Background Distributed DBMS Architecture Datalogical Architecture Implementation Alternatives Component Architecture Distributed DBMS Architecture Distributed Database Design Semantic Data Control Distributed Query Processing Distributed Transaction Management Parallel Database Systems Distributed Object DBMS Database Interoperability Current IssuesDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  2. 2. Architecture Defines the structure of the system components identified functions of each component defined interrelationships and interactions between components definedDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  3. 3. ANSI/SPARC Architecture Users External External External External Schema view view view Conceptual Conceptual view Schema Internal Internal view SchemaDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  4. 4. Standardization Reference Model A conceptual framework whose purpose is to divide standardization work into manageable pieces and to show at a general level how these pieces are related to one another. Approaches Component-based Components of the system are defined together with the interrelationships between components. Good for design and implementation of the system. Function-based Classes of users are identified together with the functionality that the system will provide for each class. The objectives of the system are clearly identified. But how do you achieve these objectives? Data-based Identify the different types of describing data and specify the functional units that will realize and/or use data according to these views.Distributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  5. 5. Conceptual Schema Definition RELATION EMP [ KEY = {ENO} ATTRIBUTES = { ENO : CHARACTER(9) ENAME : CHARACTER(15) TITLE : CHARACTER(10) } ] RELATION PAY [ KEY = {TITLE} ATTRIBUTES = { TITLE : CHARACTER(10) SAL : NUMERIC(6) } ]Distributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  6. 6. Conceptual Schema Definition RELATION PROJ [ KEY = {PNO} ATTRIBUTES = { PNO : CHARACTER(7) PNAME : CHARACTER(20) BUDGET : NUMERIC(7) } ] RELATION ASG [ KEY = {ENO,PNO} ATTRIBUTES = { ENO : CHARACTER(9) PNO : CHARACTER(7) RESP : CHARACTER(10) DUR : NUMERIC(3) } ]Distributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  7. 7. Internal Schema Definition RELATION EMP [ KEY = {ENO} ATTRIBUTES = { ENO : CHARACTER(9) ENAME : CHARACTER(15) TITLE : CHARACTER(10) } ] ⇓ INTERNAL_REL EMPL [ INDEX ON E# CALL EMINX FIELD = { HEADER : BYTE(1) E# : BYTE(9) ENAME : BYTE(15) TIT : BYTE(10) } ]Distributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  8. 8. External View Definition – Example 1 Create a BUDGET view from the PROJ relation CREATE VIEW BUDGET(PNAME, BUD) AS SELECT PNAME, BUDGET FROM PROJDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  9. 9. External View Definition – Example 2 Create a Payroll view from relations EMP and TITLE_SALARY CREATE VIEW PAYROLL (ENO, ENAME, SAL) AS SELECT EMP.ENO,EMP.ENAME,PAY.SAL FROM EMP, PAY WHERE EMP.TITLE = PAY.TITLEDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4.
  10. 10. DBMS Implementation Alternatives Distribution Distributed Peer-to-peer multi-DBMS Distributed DBMS Client/server Autonomy Multi-DBMS Federated DBMSHeterogeneity Distributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  11. 11. Dimensions of the Problem Distribution Whether the components of the system are located on the same machine or not Heterogeneity Various levels (hardware, communications, operating system) DBMS important one data model, query language,transaction management algorithms Autonomy Not well understood and most troublesome Various versions Design autonomy: Ability of a component DBMS to decide on issues related to its own design. Communication autonomy: Ability of a component DBMS to decide whether and how to communicate with other DBMSs. Execution autonomy: Ability of a component DBMS to execute local operations in any manner it wants to.Distributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  12. 12. Datalogical DistributedDBMS Architecture ES1 ES2 ... ESn GCS LCS1 LCS2 ... LCSn LIS1 LIS2 ... LISnDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  13. 13. Datalogical Multi-DBMSArchitecture GES1 GES2 ... GESn LES11 … LES1n GCS LESn1 … LESnm LCS1 LCS2 … LCSn LIS1 LIS2 … LISnDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  14. 14. Timesharing Access to a Central Database Terminals or PC terminal emulators• No data storage• Host running all software Batch Response Network requests Communications Application Software DBMS Services DatabaseDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  15. 15. Multiple Clients/Single Server Applications Applications Applications Client Client Client Services Services Services Communications Communications Communications LAN High-level Filtered requests data only Communications DBMS Services DatabaseDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  16. 16. Task Distribution Application QL Programmatic Interface … Interface Communications Manager SQL result query table Communications Manager Query Optimizer Lock Manager Storage Manager Page & Cache Manager DatabaseDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  17. 17. Advantages of Client-Server Architectures More efficient division of labor Horizontal and vertical scaling of resources Better price/performance on client machines Ability to use familiar tools on client machines Client access to remote data (via standards) Full DBMS functionality provided to client workstations Overall better system price/performanceDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  18. 18. Problems With Multiple- Client/Single Server Server forms bottleneck Server forms single point of failure Database scaling difficultDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  19. 19. Multiple Clients/Multiple Servers directory Applications caching Client query decomposition Services Communications commit protocols LAN Communications Communications DBMS Services DBMS Services Database DatabaseDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 1
  20. 20. Server-to-Server SQL interface Applications programmatic Client interface Services other application Communications support environments LAN Communications Communications DBMS Services DBMS Services Database DatabaseDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 2
  21. 21. Peer-to-Peer Component Architecture USER PROCESSOR DATA PROCESSOR Global Local System Local External Conceptual Conceptual Log Internal Schema Schema GD/D Schema SchemaUserrequests Database Local Recovery User Interface Semantic Data Global Query Local Query Controller Execution Optimizer Processor Processor Handler Manager Runtime Monitor SupportUSER GlobalSystemresponsesDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 2
  22. 22. Components of a Multi-DBMS USER Global Responses Requests GTP GUI GQP GS GRM GQOLocal Component Interface Processor Component Interface Processor LocalRequest (CIP) (CIP) Requests s User Transaction Transaction User D Interface Manager D Manager Interface B Query Scheduler B Scheduler Query M Processor … M Processor Query Recovery Recovery Query S Optimizer Manager S Manager Optimizer Runtime Sup. Runtime Sup. Processor ProcessorDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 2
  23. 23. Directory Issues Type Local & central Local & distributed Global & central & non-replicated (?) & non-replicated & non-replicated Global & distributed Local & central & non-replicated (?) & replicated (?) Location Global & central & replicated (?) Local & distributed & replicated Global & distributed & replicated ReplicationDistributed DBMS © 1998 M. Tamer Özsu & Patrick Valduriez Page 4. 2

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