None of the DELETE, TRUNCATE and DROP operations release data immediately. For the TRUNCATE and DROP operations, after the TiDB GC (Garbage Collection) time (10 minutes by default), the data is deleted and the space is released. For the DELETE operation, the data is deleted but the space is not released according to TiDB GC. When subsequent data is written into RocksDB and executes COMPACT, the space is reused.