Consistent Hashing is a distributed hashing scheme that aims to minimize the rehashing of keys when nodes are added or removed from a distributed hash table. It divides the hash space into virtual rings and maps each node to a random point on the ring, ensuring that each key is assigned to the closest node. This approach significantly reduces the number of keys that need to be remapped during topology changes, improving system stability and performance.
TakeAways
- 📌 🔢 Consistent Hashing] minimizes rehashing by mapping nodes to random points on a virtual ring.
- 💡 The technique is useful for maintaining system stability and performance in distributed hash tables.
- 🔍 Consistent Hashing significantly reduces the number of keys affected during node additions or removals, as compared to traditional hashing methods.
Process
- 🔄 Initialize a virtual ring with a large number of slots (hash values).
- 💭 Assign each node a random position on the ring using a hash function.
- ⏳ Store data (keys) in the closest node’s slot based on the hash value.
- 🔑 When adding or removing nodes, only remapping keys associated with the affected slots.
Thoughts
- 📌 Consistent Hashing helps maintain system stability by reducing rehashing during topology changes.
- 💡 The technique is particularly useful in Distributed Systems where node additions and removals are common (e.g., content delivery networks, distributed databases).
- 🔍 By mapping nodes to random positions on a virtual ring, Consistent Hashing ensures that each key is assigned to the closest node, minimizing remapping during topology changes.