To get a feel for the size of Bleve, checkout this graph that shows commit rates doing into Bleve versus Elasticsearch and Vespa:
http://blog.minimum.se/assets/elasticsearch-open-source-comm...
If you don't need heavy lifting, then "sonic" implemented in rust is a really nice lean alternative too: https://github.com/valeriansaliou/sonic
FWIW, that graph is from a blog post I published earlier today: http://blog.minimum.se/2019/04/08/elastic-search-introductio...