Data Conflict Detection and Resolution
Learn about conflict detection methods, resolution strategies, and sync queue design to maintain data integrity and build reliable, collaborative mobile applications.
In mobile applications, data conflict arises when multiple devices or users attempt to modify the same piece of data concurrently, often in distributed systems. This challenge is prevalent in many scenarios: offline-first applications, where devices work in isolation before syncing; background synchronizations; or real-time collaborative apps, where multiple users can edit the same data simultaneously.
Imagine you’re editing a document on your phone while offline. At the same time, your colleague changes the same document. When you both reconnect, how does the app know which version is correct? Without a proper strategy for detecting and resolving this conflict, data could be lost or corrupted, frustrating users and undermining the app’s reliability.
In this lesson, we’ll explore the core strategies for maintaining data integrity across all devices. We will start by examining how systems detect a conflict, and then dive into the different strategies used to resolve it.
Conflict detection strategies
Before a conflict can be resolved, a system must first be able to detect that one has occurred. This is typically achieved by creating a clear history of changes for each piece of data. Here are the most common strategies for conflict detection and avoidance.
Versioning for conflict detection
Versioning is a foundational method where each piece of data is tagged with a version identifier. When the system sees two different versions of the same data item, it knows a potential conflict exists.
Versioning simplifies conflict detection by creating a clear record of the changes made to a piece of data. This process is essential for preventing data loss, improving synchronization, and enhancing the user experience.
A simple version number (like 1, 2, 3, etc.) is often enough to identify conflicts. However, in more complex systems, versioning could involve timestamps or hash values to ensure precise conflict resolution.
There are several common strategies for implementing versioning:
Integer-based versioning: The simplest form, where a version number (1, 2, 3...) is incremented with each change. It’s easy to implement but can be challenging if many devices are offline for long periods, and make numerous changes.
Timestamp-based versioning: Every change is assigned a precise timestamp. When synchronizing, the system can use the ...