Mastering PostgreSQL 12 - Third Edition

Looking at the transaction log

In PostgreSQL, WAL can usually be found in the pg_wal directory in the data directory, unless specified otherwise on initdb. In older versions of PostgreSQL, the WAL directory was called pg_xlog, but with the introduction of PostgreSQL 10.0, the directory has been renamed.

The reason for this is that, more often than not, people would delete the content of the pg_xlog directory, which of course led to serious issues and potential database corruption. The community has therefore taken the unprecedented step of renaming a directory inside a PostgreSQL instance. The hope is to make the name scary enough that nobody dares to delete the content again.

The following listing shows what the pg_wal directory looks like: ...