pg_wal
pg_wal (in PostgreSQL 9.6 and earlier: pg_xlog) earlier is the subdirectory of the main PostgreSQL data directory where WAL files are stored.
It also contains the subdirectory archive_status..
Configuration parameters
Following configuration parameters affect the pg_wal directory in some way:
archive_commandmax_wal_sizemin_wal_sizemax_slot_wal_keep_size(PostgreSQL 13 and later)wal_keep_size(PostgreSQL 12 and earlier:wal_keep_segments)
Following configuration parameters were present in PostgreSQL versions which are now EOL:
checkpoint_segments(PostgreSQL 9.4 and earlier)
Functions
The following functions can be used to examine the contents of pg_wal:
Utilities
initdb
When executing initdb, a WAL directory location outside of the main data directory (e.g. on a different filesystem) can be specified with -X/--waldir (PostgreSQL 9.6 and earlier: -X/--xlogdir). A symbolic link from pg_wal in the main data directory to the specified location.
pg_basebackup
When executing pg_basebackup, a WAL directory location outside of the main data directory (e.g. on a different filesystem) can be specified with --waldir (PostgreSQL 9.6 and earlier: --xlogdir). A symbolic link is created from pg_wal in the main data directory to the specified location.