First, let’s create a submodule hibernate-types for extensions like this. The extension itself is for PostgreSQL and includes:

• DdlType for new SqlTypeCodes entry to map to vector($l) on PostgreSQL

• cosine_distance function for <=> operator

• euclidean_distance and l2_distance functions for the <-> operator

• taxicab_distance and l1_distance functions

• inner_product function for the <#> operator times -1

• negative_inner_product function for the <#> operator

• vector_dims function

• vector_norm function

Try supporting +, -, * operators and also the sum and avg functions.

See for details.