unexpected EOF on client connection with an open transaction

[andreaneri]

Good evening,
my setup:
go 1.18.9
github.com/jmoiron/sqlx v1.3.4
github.com/jackc/pgx/v5 v5.2.0
postgres v14

this instruction:
db.SetMaxOpenConns(dbConfig.DBMaxOpenConn) // value 1

bring this problem:
LOG: unexpected EOF on client connection with an open transaction

since i use godror driver on Oracle engine all works fine,
any idea ?
thanks

Andrea