Nov 25 07:56:19 isucon13-1 isupipe[13012]: {"time":"2023-11-25T07:56:19.951027047Z","level":"ERROR","prefix":"echo","file":"main.go","line":"244","message":"error at /api/user/:username/statistics: code=500, message=failed to count tips: missing destination name user_id in *[]main.UserStats"}
のerror