Consistency

Eventual Consistency Explained

Eventual consistency guarantees that, absent new updates, all replicas or downstream views of data will converge to the same state — but not instantly, which s…

Cosmos DB Basics

Azure's globally distributed, multi-model NoSQL database service, covering APIs, partitioning, consistency levels, and request units.

Consistency Models

Consistency models define the contract about what values reads may return after concurrent writes, ranging from strict linearizability to loosely-ordered event…

What are ACID Properties in DBMS?

ACID stands for Atomicity, Consistency, Isolation, and Durability — the four guarantees a database transaction must satisfy so that data stays correct even und…

What is CAP Theorem?

CAP theorem states that a distributed data store can only guarantee two of three properties at once — Consistency, Availability, and Partition tolerance — duri…

Write-Through vs Write-Back Cache: What is the Difference?

Write-through caching writes to the cache and the underlying database synchronously on every write, trading extra write latency for strong consistency, while w…

What is the CAP Theorem and What Trade-offs Does It Force?

The CAP theorem states that a distributed data store can provide at most two of Consistency, Availability, and Partition tolerance at the same time, and since…

What is the PACELC Theorem and How Does It Extend CAP?

PACELC extends the CAP theorem by pointing out that even when there is no network partition, a distributed system still has to trade off Latency against Consis…

What is Quorum-based Consensus and How Does It Work?

Quorum-based consensus requires a minimum number of nodes (a quorum) to agree before a read or write is considered successful, typically enforcing that the rea…

What Are the Main Data Replication Strategies?

Data replication strategies fall into three broad approaches — synchronous, asynchronous, and semi-synchronous — which trade off consistency, latency, and dura…

What Are Network Partitions in Distributed Systems?

A network partition occurs when a communication failure splits a distributed system into two or more groups of nodes that can no longer reach each other, even…

What is Clock Synchronization in Distributed Systems?

Clock synchronization is the process of keeping the independent hardware clocks on separate machines close enough in agreement that timestamp-based ordering, e…