Question 1

How to use doublejump for load balancing in Go microservices?

Accepted Answer

Import the doublejump package, create a hash instance with NewHash(), add backend nodes using Add(), and distribute requests by calling Get() with a key like a request ID. When nodes fail or are added, use Remove() and Add() to update the ring dynamically, ensuring minimal key redistribution.

Question 2

Is doublejump faster than StathatConsistent for consistent hashing in Go?

Accepted Answer

Yes, benchmarks show doublejump runs at 22-46 ns/op with zero allocations, while StathatConsistent averages 273-367 ns/op with allocations, making doublejump 10-20 times faster and more memory-efficient for high-performance scenarios.

Question 3

What changes when upgrading from doublejump V1 to V2?

Accepted Answer

V2 requires Go 1.18+ and introduces a generic interface, so you need to update imports to '/v2' and use type parameters like NewHash[string](). The Get() method also returns an additional boolean for success, improving error handling in type-safe code.

Question 4

How does doublejump handle key redistribution when nodes are removed?

Accepted Answer

It uses a revamped jump consistent hash algorithm that minimizes reshuffling; only keys mapped to the removed node are reassigned to other nodes, maintaining high consistency and performance without rehashing the entire key space.

Question 5

Doublejump or original jump hash: which is better for dynamic clusters?

Accepted Answer

Choose doublejump if you need to add or remove nodes dynamically, as the original jump hash doesn't support removal. For static node sets, both are fast, but doublejump's flexibility makes it superior for evolving systems.

Question 6

Can I benchmark doublejump against other Go hashing libraries?

Accepted Answer

Yes, use Go's testing framework to write benchmark functions that simulate your workload. The README provides example benchmarks comparing doublejump to StathatConsistent and SerialxHashring, so you can replicate those tests or adapt them for your specific nodes and keys.

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