Postgres is fine if your search problem is mostly a recall problem. If N is large enough or you have small N with enough overlapping keywords (long documents) t

Postgres is fine if your search problem is mostly a recall problem. If N is large enough or you have small N with enough overlapping keywords (long documents) then precision becomes important. That is when you need things like BM25, PageRank, machine learning, etc and Postgres just doesn't cut it anymore. Additionally spell check, high-quality autocomplete, multiple languages are better supported and much easier to implement in ES/Solr.