MyISAM tables do not support transactions. Read and write operations conflict with each other. MyISAM tables only support table-level locks. When a query or write operation takes a long time, other operations may be blocked, easily causing connection accumulation, and data may be lost after downtime. Therefore, InnoDB is recommended for ApsaraDB RDS for MySQL. If tables are imported or modified using MyISAM or rename Table, The InnoDB engine will be automatically used.