When `LoadTypes` is being called, it does not include the
namespace-qualified types in its result. While these namespaces are
visible to `LoadTypes` itself, `RegisterTypes` will not recognise this
form of the types, only allowing them to be used if they are on the
schema path, and referred to without their namespace component.
When loading even a single type into pgx's type map, multiple SQL
queries are performed in series. Over a slow link, this is not ideal.
Worse, if multiple types are being registered, this is repeated multiple
times.
This commit add LoadTypes, which can retrieve type
mapping information for multiple types in a single SQL call, including
recursive fetching of dependent types.
RegisterTypes performs the second stage of this operation.
Nick Farrell