Update redis.go

use `scan` instead of `keys`

cache/redis/redis.go

@@ -139,7 +139,7 @@ func (rc *Cache) Decr(key string) error {
 func (rc *Cache) ClearAll() error {
 	c := rc.p.Get()
 	defer c.Close()
-	cachedKeys, err := redis.Strings(c.Do("KEYS", rc.key+":*"))
+	cachedKeys, err := rc.Scan(rc.key + ":*")
 	if err != nil {
 		return err
 	}
@@ -151,6 +151,34 @@ func (rc *Cache) ClearAll() error {
 	return err
 }
 
+func (rc *Cache) Scan(pattern string) (keys []string, err error) {
+	c := rc.p.Get()
+	defer c.Close()
+	var (
+		cursor uint64 = 0 // start
+		result []interface{}
+		list   []string
+	)
+	for {
+		result, err = redis.Values(c.Do("SCAN", cursor, "MATCH", pattern, "COUNT", 1024))
+		if err != nil {
+			return
+		}
+		list, err = redis.Strings(result[1], nil)
+		if err != nil {
+			return
+		}
+		keys = append(keys, list...)
+		cursor, err = redis.Uint64(result[0], nil)
+		if err != nil {
+			return
+		}
+		if cursor == 0 { // over
+			return
+		}
+	}
+}
+
 // StartAndGC start redis cache adapter.
 // config is like {"key":"collection key","conn":"connection info","dbNum":"0"}
 // the cache item in redis are stored forever,