is it possible if min_wal_size bigger than max_wal_size ? What happen if it does ? What are the circumstances when min_wal is bigger than max_wal ?

I am using PG 12.


  • 1
    Why don't you try and then tell us?
    – mustaccio
    Jul 19, 2022 at 23:49
  • Yes. Good point. I don't know the real implication on the production system, that's why I ask before I do something horrible. I am asking this in relation to why there are so many WAL files in the directory. Someone told me that I should reduce my max_wal_size to 80MB from previously 4GB, although I have told that my min_wal_size is 1GB. So I am humbly asking what the implication of this ? I did tried it, but I haven't seen any difference. Maybe I should turn on archive_mode ON. Thanks .
    – padjee
    Jul 20, 2022 at 6:31

1 Answer 1


Yes, min_wal_size can be bigger than max_wal_size. Despite the similar names, these settings are not related to each other.

max_wal_size will trigger checkpoint after so many wal writes.

min_wal_size will always recycle wal files for future use (rather than removed) as long as WAL disk usage stays below this setting. Can be used for guaranteed space reservation for a future WAL writes.

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