As someone who has been using pgvector for a while and is vaguely curious about alternatives without having the bandwidth to investigate -- is there anything out there that offers truly differentiated advantages over pgvector? I'm extremely wary of non-OSS solutions in this area, it seems ripe for enshittification and attempts at vendor lock-in.
I'd also start with pgvector (it's easy to switch), but the limitations around hybrid search and filtering + ANN are real and if you're doing any kind of RAG-like thing it's worth being aware of them upfront. pgvector is also an open-source project with way less manpower behind it than a bunch of venture-backed companies, so while you can expect it to pick up important features, it takes much longer (support for HNSW indices was a good example).
If you're still in the "millions of documents" scale range, then PostgreSQL on a beefy EPYC can probably handle everything fast enough so that it doesn't make sense to spend engineering time on using a vector db which would only shave off a few ms in latency.
