May 2018
Intermediate to advanced
576 pages
30h 25m
English
PostgreSQL doesn't explicitly keep track of the last changed date or similar information for a file or table. PostgreSQL tables are held as files, so you should be able to rely on the modification time (mtime) of the files on the filesystem.
Another problem with this approach is that filesystem timestamps might not have a resolution that is sufficiently granular to separate all changes. This means that some additional verification, such as computing a checksum, is required to confirm that two files with the same mtime are indeed identical. If, for this or some other reason, you don't trust mtime, or it has been disabled, then incremental and differential backups are not for you.
The pg_dump utility doesn't allow WHERE clauses ...