conn.flush() will not flush all record to redis

Question

this is code

 func main() {
   ...
   pool := createPool(*redis_server, *redis_pass)
   defer pool.Close()
   c := pool.Get() 
   var i int64
   st := tickSec()
   for i = 0; i < *total; i++ {
      r := time.Now().Unix() - rand.Int63n(60*60*24*31*12)
      score, _ := strconv.Atoi(time.Unix(r, 0).Format("2006010215"))
      id := utee.PlainMd5(uuid.NewUUID().String())
      c.Send("ZADD", "app_a_5512", score, id)
      if i%10000 == 0 {
          c.Flush()
          log.Println("current sync to redis", i)
      }
  }
  //c.Flush()
  c.Close()
  ...
}

if i use c.Close(),the total set 100000,the real sortedset count 100000. but if i use c.Flush(),the total also set 100000, the real sortedset count less than 100000(96932);if i use time.Sleep() in the end of the main func,the total is 100000 too.

when main func exit,the flush func is not complete?and why? thank you!

Answer 1

The reason that the program works when Close() is called after the loop is that the pooled connection's Close() method reads and discards all pending responses.

The application should Receive the responses for all commands instead of letting the respones backup and consume memory on the server. There's no need to flush in the loop.

go func() {
  for i = 0; i < *total; i++ {
     r := time.Now().Unix() - rand.Int63n(60*60*24*31*12)
     score, _ := strconv.Atoi(time.Unix(r, 0).Format("2006010215"))
     id := utee.PlainMd5(uuid.NewUUID().String())
     c.Send("ZADD", "app_a_5512", score, id)
  }
  c.Flush()
}

for i = 0; i < *total; i++ {
   c.Receive()
}
c.Close()

Also, the application should check and handle the errors returns from Send, Flush and Receive.