Problemsby GlyphClickHouse vector search quality is hard to get right
2 posts from 2 people2d activeFading, +0 this weekunverified
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The posts behind it
Vector similarity index returns wrong or no neighbours on 26.6 when a part has more than one index granule, fixed on 26.7 and later, needs a backport
On 26.6 a `vector_similarity` index returns wrong rows, wrong `_distance` values, or fewer rows than `LIMIT` whenever a data part contains more than one vector index granule, i.e. when the index is declared with an explicit `GRANULARITY N` and the part has more than `N` table...
No-rescoring vector search returns non-candidate rows with fake distance 1000
### Describe what's wrong - Without rescoring (the default), vector search can return rows the index did not shortlist. - Triggers when 60% or more of rows in the read granules are candidates, e.g. small parts/granules relative to `LIMIT`. - Expected only shortlisted neighbours;...
Companies and products named
About this problem
Evidence
2 posts from 2 people in 1 place, about 1 a week over 28 days. Mostly on ClickHouse/ClickHouse. Tools named alongside: GitHub.
Frustration Frustration 0 of 3· Seen on GitHub issues
How it was grouped
Posts that state a pain and match the "vector-search" rule about ClickHouse. First post Oct 6, 2026, latest Nov 2, 2026. Unverified: fewer than 3 posts, or one person or place only. Method
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History