The symbol © stands for copyright. It is used to indicate that a creative work, such as a book, song, movie, or software, is legally protected. When you see this symbol, it means the creator or owner of the work has exclusive rights to control how the work is used, copied, or shared. This protection ensures that others … Read more
The Local Recovery Manager (LRM) is a crucial part of a database management system, responsible for ensuring data consistency and integrity in case of system failures. These failures may include scenarios such as system crashes, hardware malfunctions, power outages, or application failures. The LRM coordinates the entire process of restoring the database to a consistent … Read more
Lock-based protocols are a method of concurrency control in database management systems (DBMS). They ensure that multiple transactions can access the database simultaneously without violating data integrity and consistency. These protocols allow transactions to lock data items to avoid conflicts like reading inconsistent data or overwriting changes made by other transactions. In simpler terms, a … Read more
In distributed database systems (DDBMS), reliability refers to the ability of the system to functioncorrectly and consistently, even in the presence of failures or unexpected events. It ensures that thesystem can continue to provide accurate, consistent, and available data under various conditions, such asnetwork failures, hardware crashes, and data corruption.Measures to Ensure Reliability 1. Data … Read more
Network partitioning is a critical concept in the reliability of Distributed Database Management Systems(DDBMS). It refers to a situation where a network split occurs, dividing the distributed system intodisjoint sub-networks that cannot communicate with each other. Here’s a detailed discussion of networkpartitioning and its impact on DDBMS reliability: Network partitioning happens when there is a … Read more
The comparison of Lock-Based, Timestamp-Based, and Optimistic Concurrency Control Mechanisms are as follows: Feature Lock-Based Concurrency Control (LBCC) Timestamp-Based Concurrency Control (TBCC) Optimistic Concurrency Control (OCC) Approach Uses locks to control access to resources. Assigns timestamps to transactions and orders them. Allows transactions to run freely and checks for conflicts at commit time. Conflict Handling … Read more
Relaxed concurrency control (RCC) is a technique used in distributed databases to balance consistencyand performance by allowing some level of inconsistency in exchange for improved performance andscalability. Unlike traditional strict concurrency control methods, which enforce strong consistencyguarantees, RCC provides a more flexible approach that can be tailored to the specific needs of anapplication. Use Cases … Read more
Deadlock management is crucial in distributed systems to ensure smooth and efficient operation. Hereare the main strategies for handling deadlocks: detection, prevention, and avoidance: 1. Detection: Deadlock detection involves identifying deadlocks after they have occurred and taking corrective measures. 2. Prevention: Deadlock prevention involves designing the system to ensure that deadlocks cannot occur. 3. Avoidance: … Read more
Timestamp-based concurrency control (TBCC) is a technique used in database systems to manageconcurrent access to data. The goal is to ensure that transactions are executed in a way that maintainsconsistency and isolation without causing conflicts. Here’s a simplified breakdown of its role: 1. Timestamps: Each transaction is assigned a unique timestamp when it begins. This … Read more
Strict Two-Phase Locking (2PL) and Optimistic Concurrency Control (OCC) are two popular methods forensuring transaction consistency in distributed databases, each with its own advantages and trade-offs.Here’s a comparison of the two: 1. Strict Two-Phase Locking (2PL) How It Works: i. In 2PL, transactions acquire locks on data items before accessing or modifying them. The keyrule … Read more