How does IVF-PQ differ from IVF-Flat?

IVF-PQ and IVF-Flat are indexing and search methods in vector databases, often used in tasks involving searching by vector representations (for example, in systems for finding similar images or texts).

• IVF (Inverted File) is a structure that divides the vector space into several clusters (centroids). During search, the clusters closest to the query are selected first, and then the search is conducted within them.

• IVF-Flat stores all vectors within the selected clusters in a "flat" form, meaning without additional compression. Searching within a cluster is precise but requires more memory.

• IVF-PQ (Product Quantization) further compresses vectors within clusters using product quantization. This reduces memory volume and speeds up search, but the search becomes approximate with some loss of accuracy.

Summary:

• IVF-Flat provides accurate search but requires more resources.
• IVF-PQ is a compromise between speed, memory, and accuracy, allowing efficient handling of very large datasets.