Jo Kristian Bergum
Jo Kristian Bergum
Vespa Solutions Architect

Scaling vector search using Cohere binary embeddings and Vespa

Scaling vector search using Cohere binary embeddings and Vespa

Photo by Phil Botha on Unsplash

Cohere recently released a new embedding API, now featuring support for binary and int8 vectors: Cohere int8 & binary Embeddings - Scale Your Vector Database to Large Datasets.

We are thrilled to introduce Cohere Embed, the pioneering embedding model that inherently accommodates int8 and binary embeddings.

This development is significant because:

  • Binarization dramatically reduces storage requirements, compressing vectors from 1024 floats (4096 bytes) per vector to just 128 bytes.
  • Faster distance computations facilitated by hamming distance, a feature natively supported by Vespa. More insights on hamming distance in Vespa.
  • Multiple vector representations for the same text input allow for initial coarse retrieval in coarse-level hamming space, followed by subsequent phases using higher-resolution representations.
  • Significantly reduces deployment costs due to tiered storage and computations economics.

Vespa supports hamming distance calculations both with and without HNSW indexing.

For those seeking further understanding of binary vectors, it’s recommended to explore the 2021 blog series on Billion-scale vector search with Vespa and its continuation in part two. We also use a similar vector compression and binarization schema for Vespa’s colbert embedder.

About the new Cohere v3 embedding models

Cohere’s embedding models offer the versatility of multiple vector representations for a single text input, all without incurring extra charges when utilizing the embedding API. This API allows for balancing effectiveness with cost. Users can make informed trade-offs between these factors, ensuring optimal performance within their budgetary constraints.

Using the new Cohere embedding models with Vespa

We have built three comprehensive guides on using the new Cohere embedding models with Vespa.

Embed-english-v3.0 with compact binary representation

This is a great starting point for understanding Vespa’s capabilities and the new Cohere embedding models. This application uses only the most compact representation (128 bytes per vector) and includes a single re-scoring phase that lifts retrieval accuracy to 95% using the 32x larger float representation.

cohere-binary-vectors-in-vespa-cloud.html cohere-binary-vectors-in-vespa-cloud.ipynb

Embed-english-v3.0 with two vector representations

This demonstrates using two representations per text. The binary representation and the int8 version. This also features a 3-phase coarse-to-fine retrieval and ranking pipeline. These re-ranking phases improves accuracy further, but with increased storage costs (but no additional memory required).

billion-scale-vector-search-with-cohere-embeddings-cloud billion-scale-vector-search-with-cohere-embeddings-cloud.ipynb

The flagship of multilingual hybrid search. This app demonstrates combining Vespa’s support for multi-vector indexing (arrays of vectors per document embedding field) with Cohere binary embeddings.

This app combines the Cohere multilingual embeddings with lexical keyword search, including language-specific linguistic processing.

  • Indexing multiple vectors per document field: Vespa’s offers the flexibility to index multiple vectors for each document field. Instead of indexing chunks, we index pages with chunk-level vector representations using the Cohere embeddings.
  • Hybrid search with lexical linguistic processing: Combines the power of Vespa’s lexical linguistic processing with vector embeddings to deliver hybrid search.
  • Keep the context By indexing pages with chunked texts and their corresponding vector representation—retaining the page-level context. Vespa’s support for Multi-vector indexing prevents metadata duplication and eliminates the operational complexity associated with dividing the original text context into multiple rows, as is the case with single-vector databases that can only store one vector per row.

multilingual-multi-vector-reps-with-cohere-cloud multilingual-multi-vector-reps-with-cohere-cloud.ipynb


Cohere’s latest embedding models complement Vespa’s support for binary and int8 vectors, effectively minimizing costs through tiered storage and computations. The versatility of the embedding API, combined with Vespa’s features, offers a valuable opportunity for organizations looking to enhance their RAG pipelines while simultaneously lowering expenses while scaling large datasets.