--- title: "How CockroachDB Built Vector Indexing at Scale" url: https://daily.dev/posts/how-cockroachdb-built-vector-indexing-at-scale-ctsjj6qg0 source_url: https://blog.bytebytego.com/p/how-cockroachdb-built-vector-indexing type: article source: "ByteByteGo" published: 2026-05-25T15:32:57.550Z updated: 2026-05-25T15:33:24.591Z tags: ["vector-search", "cockroachdb"] reading_time: 13 upvotes: 61 comments: 2 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # How CockroachDB Built Vector Indexing at Scale **[ByteByteGo](https://daily.dev/sources/bytebytego)** · 13 min read · 61 upvotes · 2 comments ## Summary CockroachDB's engineering team built C-SPANN, a novel vector index designed to satisfy six strict architectural constraints of a distributed SQL database: no central coordinator, no large in-memory caches, minimal network hops, sharding compatibility, no hot spots, and real-time incremental updates. C-SPANN combines ideas from Microsoft's SPANN, SPFresh, and Google's ScaNN, using a hierarchical K-means tree stored as ordinary key-value table data inside CockroachDB. This design lets the index inherit existing distributed machinery — range splitting, rebalancing, replication — for free. Vectors are compressed using RaBitQ (94% size reduction) with a reranking step to recover accuracy. Multi-tenancy is handled via prefix columns, maintaining separate K-means trees per user and supporting geo-partitioning. The tradeoff: C-SPANN loses on raw latency vs. specialized in-memory vector databases but wins on transactional consistency, multi-tenant isolation, and multi-region deployment. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community discussion Top comments from developers on daily.dev. **@deepjoshi\_dev** · 2 upvotes > Name is a bit freaky though. ## Similar posts on daily.dev - [AlloyDB ScaNN index four-level tree improves vector search](https://daily.dev/posts/alloydb-scann-index-four-level-tree-improves-vector-search-y3mlioddc) · Google Cloud · 0 upvotes · 0 comments - [Decoupled by Design: Billion-Scale Vector Search](https://daily.dev/posts/decoupled-by-design-billion-scale-vector-search-puyxn3eah) · databricks · 26 upvotes · 0 comments - [The story of BigQuery vector search](https://daily.dev/posts/the-story-of-bigquery-vector-search-tmmmlqwoo) · Google Cloud · 1 upvotes · 0 comments --- Tags: [#vector-search](https://daily.dev/tags/vector-search), [#cockroachdb](https://daily.dev/tags/cockroachdb) [View this post on daily.dev](https://daily.dev/posts/how-cockroachdb-built-vector-indexing-at-scale-ctsjj6qg0)