Because if you have N connections in your pool you're going to have to execute LISTEN on all N, or else the connection pool needs to be LISTEN-aware so it can process async notifies by calling some registered callback.
I.e., the connection pool API has to be designed with this in mind.
For that matter connection pools also need to be designed with the ability to run code upon connecting to create TEMP schema elements because PG lacks GLOBAL TEMP.
Because if you have N connections in your pool you're going to have to execute LISTEN on all N, or else the connection pool needs to be LISTEN-aware so it can process async notifies by calling some registered callback.
I.e., the connection pool API has to be designed with this in mind.
For that matter connection pools also need to be designed with the ability to run code upon connecting to create TEMP schema elements because PG lacks GLOBAL TEMP.