I am relatively new to postgresql administration and I still have doubts about the operation or management of the wal files, specifically how these files are released or deleted, have the conception of Oracle which is what I know the most, where the redologs exist , which do a similar function, saving the differences, but in the case of redologs, the administrator establishes the size, quantity and specific groups, now in postgresql it is not clear to me, wals are generated to record the activity (changes) in the database, if it has a lot of activity of this type, more wal is generated, collapsing the file system, when these wal files are deleted?

1 Answer 1


WAL segments are deleted at the end of a checkpoint if they are no longer needed. A WAL segment is needed if

  • it contains information later than the latest checkpoint

  • archive_mode is not off and the segment has not been archived yet

  • it contains information later than the restart_lsn of a replication slot, and max_slot_wal_keep_size has not been exceeded

  • wal_keep_size is set high enough that the segment must be retained

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