I've been bitten by similar complexities around indirectly managing the database connection pool in Go, too. There might be a little too much magic in the library (such as successfully iterating to the end of a resultset implicitly releasing the results).
That one I'm still not clear on. I THINK I should be closing that particular rows set already, the SQL is LIMIT 1 and I check if !rows.Next(){return ...}, yet... here we are :-)
