Outline n Introduction n Background o Distributed DBMS Architecture

Transcription

1 Outlie Itroductio Backgroud o Distributed DBMS Architecture Datalogical Architecture Implemetatio Alteratives Compoet Architecture o Distributed DBMS Architecture o Distributed Desig o Sematic Data Cotrol o Distributed Query Processig o Distributed Trasactio Maagemet o Parallel Systems o Distributed Object DBMS o Iteroperability o Curret Issues Page 4. 1 Architecture Defies the structure of the system compoets idetified fuctios of each compoet defied iterrelatioships ad iteractios betwee compoets defied Page 4. 2 Page 1

2 ANSI/SPARC Architecture Users Exteral Exteral view Exteral view Exteral view Coceptual Coceptual view Iteral Iteral view Page 4. 3 Stadardizatio Referece Model A coceptual framework whose purpose is to divide stadardizatio work ito maageable pieces ad to show at a geeral level how these pieces are related to oe aother. Approaches Compoet-based u Compoets of the system are defied together with the iterrelatioships betwee compoets. u Good for desig ad implemetatio of the system. Fuctio-based u Classes of users are idetified together with the fuctioality that the system will provide for each class. u The objectives of the system are clearly idetified. But how do you achieve these objectives? Data-based u Idetify the differet types of describig data ad specify the fuctioal uits that will realize ad/or use data accordig to these views. Page 4. 4 Page 2

3 Coceptual Defiitio 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) } ] Page 4. 5 Coceptual Defiitio RELATION PROJ [ KEY = {PNO} ATTRIBUTES = { PNO : CHARACTER(7) PNAME : CHARACTER(20) BUDGET : NUMERIC(7) LOC : CHARACTER(15) } ] RELATION ASG [ KEY = {ENO,PNO} ATTRIBUTES = { ] } ENO PNO RESP DUR : CHARACTER(9) : CHARACTER(7) : CHARACTER(10) : NUMERIC(3) Page 4. 6 Page 3

4 Iteral Defiitio RELATION EMP [ KEY = {ENO} ATTRIBUTES = { ] } ENO ENAME TITLE : CHARACTER(9) : CHARACTER(15) : CHARACTER(10) INTERNAL_REL E [ INDEX ON E# CALL EMINX FIELD = { ] } E# : BYTE(9) ENAME : BYTE(15) TIT : BYTE(10) Page 4. 7 Exteral View Defiitio Ð Example 1 Create a BUDGET view from the PROJ relatio CREATE VIEW BUDGET(PNAME, BUD) AS SELECT PNAME, BUDGET FROM PROJ Page 4. 8 Page 4

5 Exteral View Defiitio Ð Example 2 Create a Payroll view from relatios EMP ad TITLE_SALARY CREATE VIEW PAYROLL (EMP_NO, EMP_NAME, SAL) AS SELECT EMP.ENO,EMP.ENAME,PAY.SAL FROM EMP, PAY WHERE EMP.TITLE = PAY.TITLE Page 4. 9 DBMS Implemetatio Alteratives Page Page 5

6 Dimesios of the Problem Distributio Whether the compoets of the system are located o the same machie or ot Heterogeeity Various levels (hardware, commuicatios, operatig system) DBMS importat oe u data model, query laguage,trasactio maagemet algorithms Autoomy Not well uderstood ad most troublesome Various versios [Veijalaie ad Pepescu-Zeleti, 1988] u Desig autoomy: Ability of a compoet DBMS to decide o issues related to its ow desig. u Commuicatio autoomy: Ability of a compoet DBMS to decide whether ad how to commuicate with other DBMSs. u Executio autoomy: Ability of a compoet DBMS to execute local operatios i ay maer it wats to. Page Datalogical Distributed DBMS Architecture... ES 1 ES 2 ES GCS... LCS 1 LCS 2 LCS... LIS 1 LIS 2 LIS Page Page 6

7 Datalogical Multi-DBMS Architecture GES 1 GES 2... GES É É LES 11 LES 1 GCS LES 1 LES m LCS 1 LCS 2 É LCS LIS 1 LIS 2 É LIS Page Timesharig Access to a Cetral No data storage Host ruig all software Termials or PC termial emulators Batch Respose requests Applicatio Software DBMS Services Network Page Page 7

8 Multiple Cliets/Sigle Server Applicatios Cliet Services Applicatios Cliet Services Applicatios Cliet Services High-level requests Filtered data oly LAN DBMS Services Page Task Distributio Applicatio QL Iterface Programmatic Iterface Maager SQL query Maager Query Optimizer result table Lock Maager Storage Maager Page & Cache Maager Page Page 8

9 Advatages of Cliet-Server Architectures More efficiet divisio of labor Horizotal ad vertical scalig of resources Better price/performace o cliet machies Ability to use familiar tools o cliet machies Cliet access to remote data (via stadards) Full DBMS fuctioality provided to cliet workstatios Overall better system price/performace Page Problems With Multiple- Cliet/Sigle Server Server forms bottleeck Server forms sigle poit of failure scalig difficult Page Page 9

10 Multiple Cliets/Multiple Servers directory cachig query decompositio commit protocols Applicatios Cliet Services LAN DBMS Services DBMS Services Page Server-to-Server SQL iterface programmatic iterface other applicatio support eviromets Applicatios Cliet Services LAN DBMS Services DBMS Services Page Page 10

11 Peer-to-Peer Compoet Architecture USER PROCESSOR DATA PROCESSOR User requests USER Exteral User Iterface Hadler Sematic Data Cotroller Global Coceptual Global Query Optimizer GD/D Global Executio Moitor Local Coceptual Local Query Processor System Log Local Recovery Maager Local Iteral Rutime Support Processor System resposes Page Compoets of a Multi-DBMS Resposes USER Global Requests GTP GS GUI GRM GQP GQO Local Requests Compoet Iterface Processor (CIP) Compoet Iterface Processor (CIP) Local Requests D B M S User Iterface Query Processor Query Optimizer Rutime Sup. Processor Trasactio Maager Scheduler Recovery Maager É D B M S Trasactio Maager Scheduler Recovery Maager Rutime Sup. Processor User Iterface Query Processor Query Optimizer Page Page 11

12 Directory Issues Type Global & cetral & o-replicated Local & cetral & o-replicated (?) Local & distributed & o-replicated Local & cetral & replicated (?) Global & distributed & o-replicated (?) Global & cetral & replicated (?) Replicatio Global & distributed & replicated Local & distributed & replicated Locatio Page Page 12