Goroutine不会遍历切片

I have this code:

for _, v := range sams {
    sam := v
    pid := getPracticeIdBySam(db, sam)

    go func() {
        defer wg.Done()

        for _, v := range pid {
            process(db, stmt, v, min_year, max_year, bar)
        }
    }()
}

It iterates through the first "pid", however it stops there. Is there a reason for this?

I found out the reason. It is because I had wg.Wait() in process which in turn caused it to hang.