从Redis / Golang客户端读取全部数据

Question

I have a Redis deployment acting as a caching layer. The cache is not very big and we would like to read all the items (key/values) at once from our Golang program. The only solution I found is to iterate through all master servers (it is a Redis cluster), execute a Scan to get all the keys and then iterate the keys to get the values.

err := cch.client.ForEachMaster(func(cl *redis.Client) error {
    wg.Add(1)
    defer wg.Done()
    var cursor uint64
    var n int
    numFor := 0
    for {

        var keys []string
        var err error
        keys, cursor, err = cl.Scan(cursor, "*", 10).Result()
        if err != nil {
            panic(err)
        }
        n += len(keys)

        for _, keyval := range keys {
            var cont Content
            if err := cch.items.Get(keyval, &cont); err == nil {

            } else {
                log.Warnf("Error getting Key %s from cache: %s from master %s", keyval, err)
            }
        }

        if cursor == 0 {
            break
        }
    }
    return nil
})
wg.Wait()

Is there a better way to do this? Cannot believe I need so many roundtrips to Redis to get the values. Thanks!

Answer 1

1) You can use KEYS command to get all the keys and then access every key. But that is not a recommended way in some cases since KEYS upon a big set of cache will cause long-blocking in Redis server. But if you just have a tiny cache, KEYS is simple and elegant command you can use.

2) You can also push the relevant keys into a hash using HSET command. So you can use HGETALL to get those key-values at once. This way can help your cache to become good-looking.