WALjournal
WALjournal is a type of file used in database systems, particularly in those employing a Write-Ahead Logging (WAL) mechanism. The primary purpose of a WAL file is to ensure data durability and recoverability. Before any changes are made to the main database data files, they are first recorded in the WAL journal. This log entry contains the modifications that are about to be made.
The write-ahead logging protocol dictates that log records must be written to persistent storage before the
WALjournals are typically sequential files, and as transactions are committed and data is flushed to disk,