When I started, I was using what was available out in the world. The vector dbs I used and even the first version I built weren't really optimized to use RAM and resources conservatively. One of the aspects of Polign is it's optimized towards cold queries and only warms the cache when needed, all while keeping the recall accuracy in acceptable range. I accepted slower first-query latency on cold data as the tradeoff. For example, the demo serves 12.5 million passages from S3 with the server idling around 37 MiB RSS (I realized there is a 20 MB gcp sdk in there).

Hosted db have query costs that grow with the corpus, and self hosted have operational overheads. They do add up over time and I wanted cost flat, which took a while to get it right.

If a vibe-coded version covers your use case, you don't need this. I have added my own experience working and optimizing the storage into this, and Im certain it holds up well for a growing corpus and with simplicity to use it across multiple readers.