We use a tape backup software that does "incremental backups"
as follows:
- In a full backup, all files are backed up.
- In an incremental backup, only the files with modification
date after the last backup are backed up.
Now when such a backup is restored, you first have to restore
the full backup, and then the incremental backup.
The problem is that files which were deleted between the full
and the incremental backup will get "resurrected" after such a
restore.
So if we perform our database backups with incremental
backups as described above, we could end up with additional
files after the restore, because PostgreSQL files can get
deleted (e.g. during DROP TABLE or TRUNCATE TABLE).
My question is:
Could such "resurrected" files (data files, files in
pg_xlog, pg_clog or elsewhere) cause a problem for the database
(other than the obvious one that there may be unnecessary files
about that consume disk space)?
Yours,
Laurenz Albe