All recordsets (at least on postgres) are coming from the primary instead of a db replica. In MDL-70997 I'm moving some of these to be normal queries as they shouldn't be recordsets anyway, but in the more general case we can decide on a case by case basis whether each cursor is able to go to a replica based on the same logic as a normal read query. But we need to store this connection state decision and then keep honoring it and flipping it as we do all the internal cursor fetching and AUX calls so that all of a given cursors actions are on the same connection.