10 Questions
What is the main purpose of concurrency control algorithms in a distributed database system?
Enforce isolation property for concurrent transactions
Which aspect of reliability do reliability measures in a distributed database system primarily enforce?
Atomicity and durability
What is the main function of distributed transaction processing in a distributed database system?
Maintain consistency and reliability of transactions across multiple sites
In a distributed database system, what does data replication primarily aim to achieve?
Enhance fault tolerance and availability of data
What is the primary role of web data management in a distributed database system?
Ensure efficient storage and retrieval of web-related data
What is the purpose of assigning unique timestamps to transactions in a distributed DBMS?
To establish a serialization order and execute transactions accordingly
What is the preferred method for assigning timestamps in a distributed DBMS to maintain uniqueness?
Use local counters with site identifiers appended for uniqueness
What is the purpose of the basic timestamp ordering (TO) algorithm?
To execute operations as soon as they are received, without causing deadlocks
In the basic TO algorithm, when is a new operation accepted by the scheduler?
If the new operation's transaction is younger than all conflicting ones already scheduled
What distinguishes the conservative TO algorithm from the basic TO algorithm?
It causes operations to wait instead of restarting them
Study Notes
Concurrency Control Algorithms
- Ensure that database transactions are executed in a correct and consistent manner, maintaining data integrity and consistency in a distributed database system.
Reliability Measures
- Primarily enforce fault tolerance, ensuring that the system can recover from failures and continue to operate correctly.
Distributed Transaction Processing
- Enables multiple operations to be executed as a single, all-or-nothing unit of work, ensuring consistency and reliability across the distributed system.
Data Replication
- Aims to achieve high availability and improved system performance by maintaining multiple copies of data in different locations.
Web Data Management
- Plays a crucial role in managing and integrating web-based data sources, enabling efficient and effective data retrieval and processing.
Assigning Unique Timestamps
- Enables the ordering of transactions, ensuring that the correct sequence of operations is maintained, and preventing conflicts and inconsistencies.
Assigning Timestamps
- The preferred method is to use a centralized timestamp generator, which ensures uniqueness and avoids conflicts.
Basic Timestamp Ordering (TO) Algorithm
- Ensures that transactions are executed in a consistent and correct order, by assigning timestamps to transactions and ordering them based on these timestamps.
Basic TO Algorithm
- A new operation is accepted by the scheduler if its timestamp is greater than the previous operation's timestamp.
Conservative TO Algorithm
- Distinguishes from the basic TO algorithm by using a more conservative approach, where an operation is only accepted if its timestamp is greater than the previous operation's timestamp, and the operation does not conflict with any previously scheduled operations.
Test your knowledge of distributed database systems with this quiz covering topics such as introduction to distributed databases, database design, query processing, distributed transactions, concurrency control, reliability, data replication, big data processing, and web data management.
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