TiDB Vector Search

Crate is an open-source, self-hosted distributed SQL database with native vector data types and similarity search for AI applications. Key features include horizontal scaling, PostgreSQL compatibility, Lucene-based indexing, and Apache 2.0 license. Ideal for RAG and real-time analytics, providing free self-hosting vs managed vector DBs like Pinecone for cost control.

ClickHouse is a columnar OLAP database with vector indexes (ANN via AMM, brute-force), supporting SQL queries over vectors + structured data at petabyte scale. Excels in aggregations with vectors. For analytics workloads with embeddings; faster ingestion than Postgres pgvector for big data.

High-performance vector database with SQL support.

Open-source search engine with support for vector and hybrid search for fast semantic retrieval.

Distributed vector engine for embedding similarity search.

Lucene KNN vector plugin for Elasticsearch search engine, enabling hybrid lexical+vector search, BM25 fusion, HNSW/IVF indexes for ANN. Used for enterprise search, RAG, multimodal apps. Integrated vs standalone like Weaviate: superior hybrid text handling but higher resource footprint.