Use Postgres built-in search functionalities instead of Elasticsearch?

[dongbohu]

Postgres has been improving full text search and trigram search a lot since version 9.6. I wonder whether it is possible to use them to replace Elasticsearch. If we can, the backend architecture (and deployment) can be greatly simplified. With the GIN or GIST indexes on search fields, we don't have to worry about the index updates (which invoke celery jobs right now).

Right now, Elasticsearch is being used to search genes and genesets. We have 312,983 genes and 408,237 genesets in Postgres backend database.