Binary represenation of XML and JSON instead of converting it to a String BEFORE transmission. Both JSON and XML essentially are graphs, and can be inflated with whitespace on the driver side AFTER transmission. Same in the other direction (deflate by transmitting binary object graph instead of whitespace-inflated String representation).
I have been actively maintaining the driver off and on since 1999 or so. Recently we have had a flurry of activity and one of the things I noticed was the surprise that PostgreSQL didn't support X or did Y in some unexpected way. Sometimes we are a bit too complacent, and accept things the way they are.
I am wondering what could the server do better that would help JDBC?
Obviously streaming a column is one. Possibly rowid's. Anything else ?