Problem with restore Discourse from backup (3.4, quite large DB)

So that’s interesting.

  • those conflicts are on fairly trivial tables and the conflicting id’s are low
  • your backup is from September and the column "notification_level" of relation "user_chat_channel_memberships" already exists migration is from October, so it has not been ran on your previous instance, and it is one of the first migrations that is done after the restore.

This sounds to me like you have a different problem. Is this a standard install? And was your previous instance a standard install? I’ve got a hunch that the backup is not restoring in the right schema and the migrations are running against a blank instance.