They are part of the hype. Lucene has vector search capabilities. Elasticsearch and Opensearch have support for that (slightly different implementations). I assume solr has similar capabilities. The combination of traditional search and vector search makes a lot of sense from a cost control point of view. Vector search at scale is expensive. The smaller the result set, the cheaper it is to do vector search over it. So using a cheap traditional search to limit the results before you run vector search makes a lot of sense.
Also, bm25 holds up well against vector search. A well tuned model can outperform it but many off the shelf models struggle to do that. Vector search is a useful tool but so far it's not a one size fits all solution that "just works". It's something that can work really well if you know what you are doing and with a lot of tuning. With things like Elasticsearch you can try both approaches.
Comments
They are part of the hype. Lucene has vector search capabilities. Elasticsearch and Opensearch have support for that (slightly different implementations). I assume solr has similar capabilities. The combination of traditional search and vector search makes a lot of sense from a cost control point of view. Vector search at scale is expensive. The smaller the result set, the cheaper it is to do vector search over it. So using a cheap traditional search to limit the results before you run vector search makes a lot of sense.
Also, bm25 holds up well against vector search. A well tuned model can outperform it but many off the shelf models struggle to do that. Vector search is a useful tool but so far it's not a one size fits all solution that "just works". It's something that can work really well if you know what you are doing and with a lot of tuning. With things like Elasticsearch you can try both approaches.