Different vector indexing algorithms under the hood, with different tradeoffs.
In this case "hnsw" is the name of the algorithm. If you want to know more, just search "hnsw" and "ivfflat" to understand the differences.
tsvector is something else; it's not a numeric vector index, it's a different kind of data structure that stores the actual lexemes (keywords) with positions and weights to facilitate full text search (rather than using a text embedding model.)
In this case "hnsw" is the name of the algorithm. If you want to know more, just search "hnsw" and "ivfflat" to understand the differences.
tsvector is something else; it's not a numeric vector index, it's a different kind of data structure that stores the actual lexemes (keywords) with positions and weights to facilitate full text search (rather than using a text embedding model.)