Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.1 Outline Introduction Background Distributed DBMS Architecture Distributed Database Design Distributed Query Processing Distributed Transaction Management n Building Distributed Database Systems (RAID) Mobile Database Systems Privacy, Trust, and Authentication Peer to Peer Systems

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.2 Useful References B. Bhargava and John Riedl, The Raid Distributed Database System, IEEE Trans on Software Engineering, 15(6), June B. Bhargava and John Riedl, A Model for Adaptable Systems for Transaction Processing, IEEE Transactions on Knowledge and Data Engineering, 1(4), Dec B. Bhargava, Building Distributed Database Systems. Y. Zhang and B. Bhargava, WANCE: Wide area network communication emulation systems, IEEE workshop on Parallel and Distributed Systems, E. Mafla, and B. Bhargava, Communication Facilities for Distributed Transaction Processing Systems, IEEE Computer, 24(8), B. Bhargava, Y. Zhang, and E. Mafla, Evolution of a communication system for distributed transaction processing in RAID, Computing Systems, 4(3), 1991.

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page LOCUS (UCLA)File system OS 2. TABS (Camelot) (CMU)Data servers OS 3. RAID (Purdue)Database level (server) 4. SDD-1 (Computer Corp. of America)Transaction manager Data manager 5. System – R* (IBM)Database level 6. ARGUS (MIT)Guardian (server) Implementations

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.4 User Transaction Parser Action Driver (ensure transaction atomicity across sites) Action Driver (interpret transactions) Action Driver (ensure serializability) compiled transactions compiled transactions compiled transactions abort or commit Concurrency Controler Atomic Controller site j, k, l,… Action Driver (interpret transactions) log//diff file Database after commit updates read only Architecture of RAID System

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.5 RAID Transactions Query Language DBMS Atomicity Controller Atomicity Controller Atomicity Controller Concurrency Controller completed transactions

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.6 RAID Distributed System RAID supports reliability transactions stable storage buffer pool management DBOS other applications OS DBMS other applications OS RAID

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.7 Local Database User Process (UI and AD) TM Process (AM, AC, CC, RC) Remote RAID Sites (2 messages) Transaction Management in one Server

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.8 Server CPU Time (second) ServerACCC Transactionusersystemusersystem Select one tuple select eleven tuples Insert twenty tuples Update one tuple ServerADAM Transactionusersystemusersystem Select one tuple select eleven tuples Insert twenty tuples Update one tuple CPU time used by RAID servers in executing transactions

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.9 Transaction1 site2 sites3 sites4 sites Select one tuple Select eleven tuples0.4 Insert twenty tuples Update one tuple0.4 RAID Elapsed Time for Transactions in seconds

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.10 Transaction1 site2 sites3 sites4 sites Select one tuple0.4 Select eleven tuples Insert twenty tuples Update one tuple RAID Execution Time in seconds

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.11 Message († multicast dest = 5) Length Bytes Raidcomm V.1  s Raidcomm V.2  s Raidcomm V.3  s SendNull MultiNull † Send Timestamp Send Relation Descriptor Send Relation Descriptor † Send Relation Send Write Relation Performance Comparison of the Communication Libraries

Distributed DBMS© 2001 M. Tamer Özsu & Patrick Valduriez Page 0.12 Experiences with RAID Distributed Database Unix influences must be factored out. Communications software costs dominate everything else. Server based systems can provide modularity and efficiency. Concurrent execution in several server types is hard to achieve. Need very tuned system to conduct experiments. Data is not available from others for validation. Expensive research direction, but is respected and rewarded.