Distributed Databases: Review May 2003Yangjun Chen1 Distributed Databases System Architecture Distributed Database Design Semantic Data Control Distributed.

Distributed Databases: Review May 2003Yangjun Chen1 Distributed Databases System Architecture Distributed Database Design Semantic Data Control Distributed Transaction Management Distributed Query Processing

Distributed Databases: Review May 2003Yangjun Chen2 System Architecture ANSI/SPARC Architecture DBMS Implementation Alternatives Datalogical Architecture Clients/Server Architecture Components of a Multi-DBMS

Distributed Databases: Review May 2003Yangjun Chen3

Distributed Databases: Review May 2003Yangjun Chen13 Distributed DBMS Design Relation Fragmentation Horizontal, Vertical, Hybrid Correctness of Fragmentation Completeness, Reconstruction, Disjointness Algorithms COM_MIN Al., Bond Energy Al. Fragment Allocation

Distributed Databases: Review May 2003Yangjun Chen20 Algorithms for horizontal fragmentation:  COM_MIN Algorithm Given a relation and a set of predicates, it will find a complete and minimal set of predicates  Horizontal Algorithm Given a complete and minimal set of predicates, it will produce a horizontal fragmentation

Distributed Databases: Review May 2003Yangjun Chen35 Global affinity measure: GAM = aff(A i, A j )*[aff(A i, A j-1 ) + aff(A i, A j+1 ) + aff(A i-1, A j ) + aff(A i+1, A j )] Since the affinity matrix is symmetric, we have GAM = 2 *aff(A i, A j )*[aff(A i, A j-1 ) + aff(A i, A j+1 )] AM = aff(A i, A j )*[aff(A i, A j-1 ) + aff(A i, A j+1 )]

Distributed Databases: Review May 2003Yangjun Chen36 Global affinity measure: AM = aff(A i, A j )*[aff(A i, A j-1 ) + aff(A i, A j+1 )] = [aff(A i, A j )*aff(A i, A j-1 ) + aff(A i, A j )*aff(A i, A j+1 )] = [bond(A i, A j-1 ) + bond(A i, A j+1 )], Where bond(A x, A y ) = aff(A z, A x )*aff(A z, A y ).

Distributed Databases: Review May 2003Yangjun Chen37 Relation schema: R[A 1, …, A i, …, A j, …, A k-1, A k, …, A n ] Affinity matrix: A 1, …, A i, …, A j, …, A k-1, A k, …, A n … … … … … Clustered affinity matrix: A i1, …, A il, A i, A j, A i(l+3), …, A i(k-1) A i1, …, A il, A i, A k, A j, A i(l+3), …, … ……… …… old new

Distributed Databases: Review May 2003Yangjun Chen38 AM old = AM old = [bond(A is, A i(s-1) ) + bond(A is, A j(s+1) )] + bond(A i, A il ) + bond(A i, A j ) + bond(A j, A i ) + bond(A j, A i(l+3) ) + [bond(A is, A i(s-1) ) + bond(A is, A j(s+1) )] AM new = AM new = [bond(A is, A i(s-1) ) + bond(A is, A j(s+1) )] + bond(A i, A il ) + bond(A i, A k ) + bond(A k, A i ) + bond(A k, A j ) + bond(A j, A k ) + bond(A j, A i(l+3) ) + [bond(A is, A i(s-1) ) + bond(A is, A j(s+1) )] AM new AM old = 2* AM new – AM old = 2* bond(A i, A k ) + 2* bond(A j, A k ) – 2* bond(A i, A j )

Distributed Databases: Review May 2003Yangjun Chen51 total cost cost for query processing cost for storage cost for data processing cost for transmission cost for data access cost for integrity checking cost for concurrency control update cost retrieval cost

Distributed Databases: Review May 2003Yangjun Chen52 Semantic Data Control View Management Data Security Semantic Integrity Control Constraint Specification Language Integrity Enforcement

Distributed Databases: Review May 2003Yangjun Chen62 Distributed Query Processing Query Processing Methodology -Query Decomposition -Data Localization -Global Optimization -Local Optimization

Distributed Databases: Review May 2003Yangjun Chen78 R* Algorithm SDD-1 Algorithm

Distributed Databases: Review May 2003Yangjun Chen91 Distributed Transaction Management Transaction Concepts and Models Distributed Concurrency Control Distributed 2PL Timestamp Ordering Optimistic Concurrency Control Deadlock

Distributed Databases: Review May 2003Yangjun Chen103 Phenomenadescription P1 dirty read (transaction can read data that is not committed) P2nonrepeatable read (transaction can read the same row twice, and it could be different) P3phantom

Distributed Databases: Review May 2003Yangjun Chen104 Phenomena occurs? P1P2P3 serializablenonono repeatable readnonoyes read committednoyesyes read uncommittedyes yesyes

Distributed Databases: Review May 2003Yangjun Chen1 Distributed Databases System Architecture Distributed Database Design Semantic Data Control Distributed.

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Distributed Databases: Review May 2003Yangjun Chen1 Distributed Databases System Architecture Distributed Database Design Semantic Data Control Distributed.

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