What Are WALs and Log File Paths?

Answer: In a system using write-ahead logs (WALs or Xlogs), all data file modifications are written to a log before they are applied. That is, the corresponding log must be written into a permanent memory before a data file is modified. They are also called redo logs.

WALs can be used to restore a damaged database when the system breaks down due to database damage. The path is Data directory/pg_xlog. Take a database node as an example. The directory is /gaussdb/data/data_dn/pg_xlog, where /gaussdb/data/data_dn indicates the data directory of the database node.