* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download 슬라이드 1
Survey
Document related concepts
Microsoft Access wikipedia , lookup
Entity–attribute–value model wikipedia , lookup
Global serializability wikipedia , lookup
Tandem Computers wikipedia , lookup
Oracle Database wikipedia , lookup
Commitment ordering wikipedia , lookup
Ingres (database) wikipedia , lookup
Extensible Storage Engine wikipedia , lookup
Microsoft SQL Server wikipedia , lookup
Functional Database Model wikipedia , lookup
Open Database Connectivity wikipedia , lookup
Serializability wikipedia , lookup
Microsoft Jet Database Engine wikipedia , lookup
Relational model wikipedia , lookup
Versant Object Database wikipedia , lookup
Database model wikipedia , lookup
Clusterpoint wikipedia , lookup
Transcript
Pusan National University em Spatiotemporal Database Laboratory File Processing : Database Management System Architecture 2004, Spring Pusan National University Ki-Joune Li Pusan National University Spatiotemporal Database Laboratory em Architecture of DBMS Client-Server Model Parallel Database System Distributed Database System Pusan National University em Client-Server Systems Server systems satisfy requests generated at m client systems Spatiotemporal Database Laboratory Clients are geographically distributed or Clients are located in the same machine of server Pusan National University em Server Systems Server systems can be broadly categorized into two kinds: Spatiotemporal Database Laboratory transaction servers which are widely used in relational database systems, and data servers, used in object-oriented database systems Pusan National University em Transaction Servers Also called Spatiotemporal Database Laboratory query server systems or SQL server systems; clients send requests to the server system Requests specified in SQL, and communicated to the server through RPC mechanism. Transactional RPC allows many RPC calls to collectively form a transaction. Open Database Connectivity (ODBC) is a C language JDBC standard similar to ODBC, for Java Pusan National University em Transaction Server Process Structure A typical transaction server consists of multiple processes accessing data in shared memory. Server processes Spatiotemporal Database Laboratory Lock manager process These receive user queries (transactions), execute them and send results back Processes may be multithreaded, allowing a single process to execute several user queries concurrently Typically multiple multithreaded server processes More on this later Database writer process Output modified buffer blocks to disks continually Pusan National University em Transaction Server Processes Log writer process Spatiotemporal Database Laboratory Checkpoint process Server processes simply add log records to log record buffer Log writer process outputs log records to stable storage. Performs periodic checkpoints Process monitor process Monitors other processes, and takes recovery actions if any of the other processes fail E.g. aborting any transactions being executed by a server process and restarting it Pusan National University em Parallel Systems Parallel database systems consist of Spatiotemporal Database Laboratory Granularity multiple processors and multiple disks connected by a fast interconnection network. A coarse-grain parallel machine A massively parallel or fine grain parallel machine Two main performance measures: throughput --- the number of tasks that can be completed in a given time interval response time --- the amount of time it takes to complete a single task from the time it is submitted Pusan National University em Parallel Database Architectures Spatiotemporal Database Laboratory Shared memory -- processors share a common memory Shared disk -- processors share a common disk Shared nothing -- processors share neither a common memory nor common disk Hierarchical -- hybrid of the above architectures Spatiotemporal Database Laboratory Pusan National University em Parallel Database Architectures Pusan National University em Distributed Systems Spatiotemporal Database Laboratory Data spread over multiple machines (also referred to as sites or nodes. Network interconnects the machines Data shared by users on multiple machines Pusan National University em Distributed Databases Homogeneous distributed databases Spatiotemporal Database Laboratory Heterogeneous distributed databases Same software/schema on all sites, data may be partitioned among sites Goal: provide a view of a single database, hiding details of distribution Different software/schema on different sites Goal: integrate existing databases to provide useful functionality Differentiate between local and global transactions A local transaction accesses data in the single site at which the transaction was initiated. A global transaction either accesses data in a site different from the one at which the transaction was initiated or accesses data in several different sites. Pusan National University em Trade-offs in Distributed Systems Spatiotemporal Database Laboratory Sharing data Autonomy Higher system availability through redundancy Disadvantage: added complexity required to ensure proper coordination among sites. Software development cost. Greater potential for bugs. Increased processing overhead.