PouchDB handles data synchronization in a distributed environment using a combination of replication, conflict resolution, and eventual consistency mechanisms. Here's how the process works:
Replication :
* PouchDB uses Apache CouchDB's replication protocol to synchronize data between multiple instances of PouchDB or CouchDB databases.
* Replication can occur in both directions (bidirectional), meaning changes made to the data on one database are replicated to the other database, and vice versa.
* Replication can be initiated manually or set up to occur automatically at regular intervals or in real-time using continuous replication.
Conflict Detection and Resolution :
* During replication, PouchDB detects conflicts that may arise when conflicting changes are made to the same document on different databases.
* PouchDB provides conflict resolution mechanisms to reconcile conflicts and ensure data consistency.
* By default, PouchDB uses a Last-Write-Wins (LWW) conflict resolution strategy, where the most recent change to a document takes precedence.
* However, developers can implement custom conflict resolution policies based on their application's requirements to handle conflicts more effectively.
Eventual Consistency :
* PouchDB aims to achieve eventual consistency between the distributed databases, meaning that over time, all changes made to the data will be replicated and applied consistently across all databases.
* While immediate consistency may not always be guaranteed due to network latency and other factors, eventual consistency ensures that data eventually converges to a consistent state.
* Eventual consistency allows applications to continue functioning even in the presence of network partitions or temporary disruptions, ensuring that data remains accessible and up-to-date across distributed environments.
Conflict-Free Replication :
* PouchDB incorporates conflict-free replication (CRDT) techniques to minimize conflicts and ensure data consistency without the need for centralized coordination.
* CRDTs enable data to be replicated across distributed databases in a conflict-free manner, allowing replicas to converge to a consistent state without requiring explicit conflict resolution.
