fix(redis): replace KEYS with SCAN for better performance

Replace Redis KEYS command with SCAN to improve performance on large datasets.
The KEYS command can block the Redis server when dealing with many keys,
while SCAN provides cursor-based iteration that is non-blocking.

Fixes #618

Co-authored-by: H <[email protected]>

Author: claude[bot]

core/src/plugins/redis/redis.go

@@ -77,10 +77,24 @@ func (p *RedisPlugin) GetStorageUnits(config *engine.PluginConfig, schema string
 	}
 	defer client.Close()
 
-	keys, err := client.Keys(ctx, "*").Result()
-	if err != nil {
-		log.Logger.WithError(err).Error("Failed to retrieve Redis keys")
-		return nil, err
+	// Use SCAN instead of KEYS for better performance
+	var keys []string
+	var cursor uint64
+	
+	for {
+		var scanKeys []string
+		scanKeys, cursor, err = client.Scan(ctx, cursor, "*", 0).Result()
+		if err != nil {
+			log.Logger.WithError(err).Error("Failed to scan Redis keys")
+			return nil, err
+		}
+		
+		keys = append(keys, scanKeys...)
+		
+		// When cursor is 0, we've completed the full scan
+		if cursor == 0 {
+			break
+		}
 	}
 
 	pipe := client.Pipeline()