阿里云服務(wù)器有時(shí)會(huì)出現(xiàn)由于dns解析問(wèn)題造成的短暫不能訪問(wèn)數(shù)據(jù)庫(kù)服務(wù)器（RDS）的問(wèn)題System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible.請(qǐng)問(wèn)有什么開(kāi)銷最低的方式可以檢查數(shù)據(jù)庫(kù)連接是否正常？這樣可以通過(guò)負(fù)載均衡的健康檢查及時(shí)發(fā)現(xiàn)，不影響應(yīng)用的正常運(yùn)行。