I have an application that is about 400 views per second and 100 entries per second for redis (hosted on redislabs). The application uses the package github.com/garyburd/redigoas a redis proxy.
I have two functions that are used only for reading and writing:
func getCachedVPAIDConfig(key string) chan *cachedVPAIDConfig {
c := make(chan *cachedVPAIDConfig)
go func() {
p := pool.Get()
defer p.Close()
switch p.Err() {
case nil:
item, err := redis.Bytes(p.Do("GET", key))
if err != nil {
c <- &cachedVPAIDConfig{nil, err}
return
}
c <- &cachedVPAIDConfig{item, nil}
default:
c <- &cachedVPAIDConfig{nil, p.Err()}
return
}
}()
return c
}
func setCachedVPAIDConfig(key string, j []byte) chan error {
c := make(chan error)
go func() {
p := pool.Get()
defer p.Close()
switch p.Err() {
case nil:
_, err := p.Do("SET", key, j)
if err != nil {
c <- err
return
}
c <- nil
default:
c <- p.Err()
return
}
}()
return c
}
As you can see, I use the recommended pooling mechanism ( http://godoc.org/github.com/garyburd/redigo/redis#Pool ).
I call these functions with every HTTP request that the application endpoint receives. The problem is this: after the application starts receiving requests, it immediately starts throwing an error
dial tcp 54.160.xxx.xx:yyyy: connect: cannot assign requested address
(54.160.xxx.xx: yyyy - redis node)
redis, 600 , , .
MaxActive pool, - 1000 50 , .
?
( func init):
pool = redis.Pool{
MaxActive: 1000,
Dial: func() (redis.Conn, error) {
c, err := redis.Dial("tcp", redisHost)
if err != nil {
return nil, err
}
if _, err := c.Do("AUTH", redisPassword); err != nil {
c.Close()
return nil, err
}
return c, err
},
}
2:
, !
init:
pool = redis.Pool{
MaxActive: 500,
MaxIdle: 500,
IdleTimeout: 5 * time.Second,
Dial: func() (redis.Conn, error) {
c, err := redis.DialTimeout("tcp", redisHost, 100*time.Millisecond, 100*time.Millisecond, 100*time.Millisecond)
if err != nil {
return nil, err
}
if _, err := c.Do("AUTH", redisPassword); err != nil {
c.Close()
return nil, err
}
return c, err
},
}
init , get set redigo , getCachedVPAIDConfig setCachedVPAIDConfig. :
func setCachedVPAIDConfig(key string, j []byte) error {
p := pool.Get()
switch p.Err() {
case nil:
_, err := p.Do("SET", key, j)
p.Close()
return err
default:
p.Close()
return p.Err()
}
}
func getCachedVPAIDConfig(key string) ([]byte, error) {
p := pool.Get()
switch p.Err() {
case nil:
item, err := redis.Bytes(p.Do("GET", key))
p.Close()
return item, err
default:
p.Close()
return nil, p.Err()
}
}