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Group: distributed database
topics >
computer science >
optimistic update for concurrency control
Topic:
replicated data
Topic:
updating information in a distributed system
Topic:
updating information in Clearinghouse and Grapevine
Topic:
updating information with locking
Topic:
updating information with rumor mongering and random updates
distributed systems
Topic:
concurrency control by sequencers
Topic:
database transactions
Topic:
hypertext as a distributed system
Topic:
implementing distributed systems and applications
Topic:
heterogeneous database
Topic:
multi-user systems
Topic:
multiple processors
Topic:
specification and design of distributed systems
Topic:
timestamps
Topic:
translation of data
Topic:
using hypertext for cooperative work
Summary
A database may be distributed over many processors interconnected by a network. All networks can be seen as distributed databases, but the ones of special interest have shared components which are managed on a global scale. The goal is to keep all shared databases updated without a lot of network activity. In general exactly equivalent databases are not required, but each database should become equivalent after network inactivity. During network activity the databases remain internally consistent, and modifications are eventually propagated to all databases. T timestamps organize object modifications so that each transaction uses a consistent set of object values. (cbb 5/80)
Subtopic: ADMS -- mainframe database plus workstation caches
Quote: new operating systems needed for extended databases used by separate modules; e.g., airline reservations and project management [»balzRM_1986] Quote: for a data server, record-at-a-time DML statements are the wrong unit for interprocess communication; need to minimize messages [»maryF_1982] Quote: separate access module from the data server; move selected tuples to the workstation, then deliver one at a time [»maryF_1982]
Subtopic: SDD-1 -- distributed database
Quote: ADMS+- integrates ADMS+ on a mainframe with a large number of workstation databases called ADMS- Quote: ADMS- is a trimmed version of ADMS+ without security and concurrency control subsystems [»rousN12_1986] Quote: ADMS- is an intelligent cache database access subsystem for ADMS+ [»rousN12_1986] Quote: in ADMS+-, common access paths are globalized on ADMS+ while rare ones are localized on ADMS- at the requesting workstation [»rousN12_1986] Quote: ADMS+- assumes a high bandwidth with no delay between workstations and mainframe [»rousN12_1986]
Subtopic: Pegasus -- heterogeneous, distributed DB with a common view
Quote: SDD-1 supports a distributed database that expands by adding new sites and moderate-size computers [»bernPA5_1978] Quote: SDD-1 manages the retrieval of distributed data and the updating of shared copies [»bernPA5_1978]
Subtopic: standards
Quote: Pegasus is a heterogeneous, multidatabase management system developed by Hewlett-Packard; object-oriented and relational [»ahmeR12_1991] Quote: a Pegasus schema makes a local data source appear as Pegasus database; maps between data models and query languages [»ahmeR12_1991] Quote: a heterogeneous database may need a common view despite different definitions, algorithms, and units; users can specify the mappings [»ahmeR12_1991]
QuoteRef: burrWE8_1983 ;;An Overview of the proposed american national standard for local distributed data interfaces
Topic: optimistic update for concurrency control (35 items)
Topic: replicated data (51 items)
Topic: updating information in a distributed system (50 items)
Topic: updating information in Clearinghouse and Grapevine (11 items)
Topic: updating information with locking (20 items)
Topic: updating information with rumor mongering and random updates
(13 items)
Group: distributed systems (14 topics, 348 quotes)
Topic: concurrency control by sequencers (27 items)
Topic: database transactions (27 items)
Topic: hypertext as a distributed system (4 items)
Topic: implementing distributed systems and applications (41 items)
Topic: heterogeneous database (6 items)
Topic: multi-user systems (4 items)
Topic: multiple processors (10 items)
Topic: specification and design of distributed systems (14 items)
Topic: timestamps (19 items)
Topic: translation of data (26 items)
Topic: using hypertext for cooperative work
(9 items)