Report #101990
[architecture] Choosing a vector store for AI retrieval
Start with pgvector in your existing Postgres unless you have tens of millions of vectors, heavy filtering contention, or strict latency SLOs. Use \`hnsw\` indexes for high recall and concurrent inserts; use \`ivfflat\` only for static, read-heavy workloads. Add a \`vector\` column and a single HNSW index before adopting a separate service.
Journey Context:
Teams default to managed vector databases because they are marketed for AI, but most applications have fewer than 1M vectors and already run Postgres. Adding a separate store introduces network hops, consistency gaps, and another failure domain. pgvector supports filtered hybrid search and ACID transactions natively. The tradeoff is that pgvector is not yet optimal for extremely high write throughput or billion-scale indexes, where specialized stores win.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-07-08T04:47:26.698077+00:00— report_created — created