Several difficult concepts in ORACLE

Latch indicates the locking mechanism that occurs when processing data between running processes of the Oracle database.

Lock, which indicates the differential locking mechanism when concurrency occurs between specific objects in the oracle database, including table locking and record locking.

Logical I/O indicates the read and write operations that occur when data is read from the cache. Only when data is processed in the memory.

Physical I/O indicates the operation to read and write data from disks, tapes, and other devices. For example, redo log file read and write, data file read and write, dirty data is written from the cache to the data file, and so on.