Indexing in a vector engine is what gives you similarity search faster than brute force. The type of engine is what gives you various different distance measur

Indexing in a vector engine is what gives you similarity search faster than brute force. The type of engine is what gives you various different distance measures (often approximate). Redis specifically has two choices: brute force (which is precise and slow), or HNSW (which is approximate and fast, but space-consuming for interesting dimensionality).