> Why would one use Algolia over Postgres's built in text search features? Ex:
http://rachbelaid.com/postgres-full-text-search-is-good-enou....
Postgres built-in search features are really for large document searching -- we've tried using it for indexing e.g. an array of tags for auto-complete and the search times were in the ~500ms+ range, as a matter of fact the non-indexed regex search was only slightly slower. I thought the later was rather surprising - but asking on the mailing-lists, I was told that this was basically working as intended.
edit: I don't fully understand the value-proposition of Algolia either, most of the trouble with going outside of your production database for search - is the problem of keeping your data in sync and current with the production database; compared to that setting up an Elasticsearch cluster really isn't such a big deal, there are also half-way solutions, for example Amazon has an Elasticsearch-service.