Distributed Databases Questions
The ACID properties in distributed databases refer to a set of characteristics that ensure reliability, consistency, and integrity of data across multiple nodes or locations in a distributed system.
1. Atomicity: This property ensures that a transaction is treated as a single, indivisible unit of work. It guarantees that either all the operations within a transaction are successfully completed, or none of them are. If any part of the transaction fails, the entire transaction is rolled back, and the database returns to its previous state.
2. Consistency: Consistency ensures that a transaction brings the database from one valid state to another. It enforces integrity constraints, business rules, and predefined relationships, ensuring that data remains valid and consistent throughout the transaction. If a transaction violates any of these constraints, it is rolled back, and the database remains unchanged.
3. Isolation: Isolation ensures that concurrent transactions do not interfere with each other. Each transaction is executed in isolation, as if it were the only transaction running on the system. This prevents data inconsistencies and conflicts that may arise when multiple transactions access and modify the same data simultaneously.
4. Durability: Durability guarantees that once a transaction is committed, its effects are permanent and will survive any subsequent failures, such as power outages or system crashes. The changes made by a committed transaction are stored in a durable storage medium, such as disk, ensuring that they are not lost and can be recovered in case of failures.
These ACID properties are crucial in distributed databases to maintain data integrity, consistency, and reliability across multiple nodes or locations, even in the presence of failures or concurrent transactions.