--- title: "Release notes" slug: "dev-vector-search-release-notes" description: "Explore VAST Cluster 5.5's vector indexing capabilities, release updates, and limitations for enhanced vector search performance and accuracy." updated: 2026-10-30T18:18:51Z published: 2026-10-30T18:18:51Z canonical: "docs.vastdata.com/dev-vector-search-release-notes" --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.vastdata.com/llms.txt > Use this file to discover all available pages before exploring further. # Release notes *Applies to VAST Cluster 5.5. Examples use the VAST DataBase Python SDK 2.1.0.* This page lists what VAST Cluster 5.5 supports for VAST Vector Search, what each 5.5 release added, and the known limitations. It's a digest of the [VAST Cluster 5.5.0 release notes](/docs-5-5/docs/vast-cluster-5-5-0-release-notes#vector-indexing) and their service packs. For changes to VAST DataBase as a whole, see the VAST DataBase [release notes](/develop/docs/dev-database-release-notes). To find out which release your cluster runs, see [find your versions](/develop/docs/dev-database-reference-versions#find-your-versions). For which Python SDK, ADBC driver and connector versions go with each release, see [version compatibility](/develop/docs/dev-database-reference-versions). ## What VAST Cluster 5.5 supports | Capability | VAST Cluster 5.5 | | --- | --- | | `VECTOR(FLOAT, d)` and `VECTOR(FLOAT16, d)` columns, and the SQL distance functions | Yes | | Vector index, declared when you create the table (`VECTOR CLUSTER BY` in SQL, `create_table(vector_index=...)` in the Python SDK, `vector_indexes` in the VMS REST API) | Yes. See [create an index](/develop/docs/dev-vector-search-guides-create-an-index). | | Distance metrics `l2sq`, `cosine` and `ip`, for the index and for search | Yes | | Quantization `scalar_8bit` (the default, for clustering and search) and `none`, set separately for clustering and search | Yes. Not every pair is allowed; see [quantization](/develop/docs/dev-vector-search-guides-quantization). | | RaBitQ quantization | No | | Secondary index (`SECONDARY INDEX`, `INCLUDE`) | No. Filter with `WHERE`; see [filters](/develop/docs/dev-vector-search-guides-filters). | | Search through the VAST Query Engine (Query Engine virtual IP pool), with ADBC or the Python SDK | Yes. See [setup](/develop/docs/dev-vector-search-operations-setup). | | Search session settings, passed as ADBC connection options | Yes. See [search session settings](/develop/docs/dev-vector-search-reference-configuration). | | Python SDK `VectorIndexSpec` and `vector_search()` | Yes, with SDK 2.1.0. On `ip` tables, search with SQL instead; see [Python SDK](/develop/docs/dev-vector-search-integrations-python-sdk#inner-product-indexes-search-with-sql). | | Index-based search from the Trino or Spark connector | No | | Add an index to an existing table, or remove one | No | | Add or drop columns on a vector-indexed table | No | | Update the vector column | No. Delete the row and insert it again. Updating other columns works. | | Vector index on a sorted or partitioned table | No | | Replication of vector-indexed tables | No See [limits](/develop/docs/dev-database-reference-limits#combining-table-structures). | Searches use the index only if they have the shape it needs: one distance, ascending, with `LIMIT k` and no `OFFSET`. Other searches run as full scans. See [query design](/develop/docs/dev-vector-search-guides-query-design). For each limit in detail, see [limits](/develop/docs/dev-vector-search-reference-limits). ## 5.5.0 ### What you can now do **Vector indexing.** VAST DataBase tables can now have a vector index. A table with a vector index arranges its data by the vector distances of one vector column, so similarity searches are faster and more accurate and use less compute. - You choose the distance metric when you create the index. - With the VAST Query Engine, use `CREATE TABLE ... VECTOR CLUSTER BY`. See [create an index](/develop/docs/dev-vector-search-guides-create-an-index). - In the VAST Web UI, your platform team enables the **Vector indexing** capability when they create a table with a vector column, then chooses the column and the distance function ([Managing tables](/docs-5-5/docs/managing-tables#configuring-vector-indexing)). - The VMS REST API `/tables/` endpoint takes the index as a `vector_indexes` array, and an index can only be declared when the table is created: `/tables/add_columns/` on an indexed table fails with HTTP 400 `adding columns on indexed tables is forbidden`. See [CI/CD and automation](/develop/docs/dev-vector-search-operations-ci-cd#you-cant-add-an-index-to-an-existing-table). - Newly inserted vectors can be searched straight away. The index catches up with them in the background, which can take some time. The cluster accepts three distance metrics: `l2sq` (Euclidean), `cosine` and `ip` (inner product). ### Known limitations These are listed in the 5.5.0 release notes and repeated unchanged in SP2, SP3 and SP6. **Vector-indexed tables** - Once vector indexing is enabled for a table, it can't be disabled. - After a vector index is created, its distance function can't be changed. - Only one vector column can be indexed per table. - The word `vector` can't be used as the vector column name. - Adding a vector index to an existing table isn't supported. - Adding or deleting columns in an indexed table isn't supported. - Vector indexing can't be used together with sorted tables or partitioned tables. - In the release notes' words: "VAST Connectors for Trino, Spark and Dremio do not support vector index-based search." **VAST Query Engine** - Virtual IP pools with the Query Engine role can't be modified after they're created. To change one, your platform team deletes it and creates a new one, so expect the Query Engine address to change if they do. See [setup](/develop/docs/dev-vector-search-operations-setup). ## 5.5.0-SP2 No new vector search features or fixes. The known limitations are the same as 5.5.0. ([5.5.0-SP2 release notes](/docs-5-5/docs/vast-cluster-5-5-0-sp2-release-notes)) ## 5.5.0-SP3 No new vector search features or fixes. The known limitations are the same as 5.5.0. ([5.5.0-SP3 release notes](/docs-5-5/docs/vast-cluster-5-5-0-sp3-release-notes)) ## 5.5.0-SP6 No new vector search features or fixes. The known limitations are the same as 5.5.0. ([5.5.0-SP6 release notes](/docs-5-5/docs/vast-cluster-5-5-0-sp6-release-notes)) ## See also - [Limits](/develop/docs/dev-vector-search-reference-limits): what can't be changed after creation, and why. - [Move vectors into an indexed table](/develop/docs/dev-vector-search-guides-migrate). - VAST DataBase [release notes](/develop/docs/dev-database-release-notes) and [version compatibility](/develop/docs/dev-database-reference-versions).