AI article
pgvector HNSW Filtering: My RAG Asked for 10 Rows and Got 0
Community description: pgvector HNSW filtering runs your WHERE clause after the index scan, so filtered RAG queries return fewer rows than LIMIT. Here's the fix.
Dev.to | Oct 4, 2026 | jidonglab
Automated excerpt
Expected rows returned ≈ ef_search × selectivity. Why does pgvector HNSW filtering return fewer rows than LIMIT? Your test tenant is probably your biggest tenant, or your only tenant.
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