18 Questions
What is one potential advantage of a distributed database system mentioned in the text?
Reduced contention for CPU and I/O services
What is the purpose of breaking up a single query into several subqueries in a distributed database system?
Achieving intra-query parallelism
Which factor contributes to reducing delays in a distributed database system?
Localization of data
What is a key requirement for achieving parallelism in executing multiple queries in a distributed database system?
Inter-query parallelism
Which technology emergence impacted the issue of database scaling according to the text?
Microprocessor and workstation technologies
How does full replication of data contribute to ensuring mutual consistency in a distributed database system?
By maintaining multiple copies of the same data
What is the main characteristic of pull-based delivery in data delivery alternatives?
Clients have to explicitly request data from the server.
In a distributed database system, how are processors at different sites interconnected?
By a computer network
What does D-DBMS stand for in the context of databases?
Distributed Database Management System
Which dimension is NOT part of the three orthogonal dimensions in data delivery alternatives (DDA)?
Query processing methods
What is the main difference between a distributed database and a collection of files?
A distributed database uses a relational data model.
Which type of system involves the transfer of data from servers to clients initiated by a client pull?
Pull-only system
What is the main reason for distributing processing in distributed computing?
To delegate various functions to different hardware or software
Which of the following is an example of a distributed application?
A cloud computing platform
In the context of distributed computing, what does data independence refer to?
Data being accessible from multiple processing sites
Which statement best describes the role of a Distributed Database Management System (DBMS)?
Coordinating data manipulation at multiple sites
Why is distributed processing considered essential for various computer applications today?
To align with the distributed nature of organizations
What is a key characteristic of distributed computing systems?
Autonomous elements interconnected by a network
Study Notes
Database Management Application
- Application programs interact with the DBMS, which provides description, manipulation, and control of the database.
- Multiple application programs can interact with the DBMS, each with its own data semantics.
Motivation for Distributed Database Systems
- Integration of database technology and computer networks leads to distribution, not centralization.
- Distributed DBMS integrates data from multiple processing sites.
Distributed Computing
- Autonomous processing elements, interconnected by a computer network, cooperate to perform tasks.
- Distribution can be in processing logic, processing elements, functions, data, or control.
Advantages of Distributed Computing
- Better fits organizational structure of today's applications.
- Advantages include:
- Reduced contention for CPU and I/O services.
- Reduced remote access delays.
Parallelism Requirements
- Inter-query parallelism: executing multiple queries simultaneously.
- Intra-query parallelism: breaking up a single query into subqueries executed at different sites.
Data Replication
- Full replication: having all required data at each site.
- Issues with updates: maintaining mutual consistency and freshness of copies.
System Expansion
- Database scaling: a key issue.
- Emergence of microprocessor and workstation technologies.
- Demise of Grosh's law.
- Client-server model of computing.
Distributed DBMS Characteristics
- A database, not a collection of files.
- Data logically related as exhibited in users' access patterns.
- Relational data model.
- A full-fledged DBMS, not a remote file system or TP system.
Distributed DBMS Environment
- Multiple sites connected by a communication network.
- Each site may have its own DBMS.
Data Delivery
- Data delivery alternatives (DDA) have three dimensions:
- Delivery modes.
- Delivery frequency.
- Communication methods.
- Pull-only delivery mode: client-initiated data transfer from servers.
Test your knowledge on database management, distributed computing, and data semantics based on chapters 1 to 6 from the book co-authored by M.T.Özsu and P.Valduriez.
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