Type: integer
Default: 1024 (1GB)
Min: 2 (2MB)
Max: 2147483647 (2147483647MB)
Unit: MB
Context: sighup
Restart: false
Since: 9.5

Maximum size to let the WAL grow during automatic checkpoints. This is a soft limit; WAL size can exceed max_wal_size under special circumstances, such as heavy load, a failing archive_command or archive_library, or a high wal_keep_size setting. If this value is specified without units, it is taken as megabytes. The default is 1 GB. Increasing this parameter can increase the amount of time needed for crash recovery. This parameter can only be set in the postgresql.conf file or on the server command line.


… except for databases that write more than 1GB/hour of data, in which case increase the size of the log so that it's at least an hour worth of logs