Hi,
Dne 12. 10. 21 v 15:21 Dimitry Sibiryakov napsal(a):
BACKUP:
Backup of separate partition is something nobody asked for so far. At
least I cannot remember a ticket for gbak accepting filter condition
inside of a table, only filter for whole tables and (since it is already
implemented)... is anybody aware of it?..
Actually, it may make a lot of sense. Imagine that partitioning is used
to separate historic records to partitions by years (for example). As
historic data are not changed, the current year is (new records), so it
may make sense to backup only the "active" partitions. In light of that,
it may be a nice feature if partition would have an "updated" flag, and
gbak an option to backup only changed partitions.
RESTORE:
How backup of single partition is supposed to be restored or
otherwise used?
For gbak it does not really matter, as it restores what is found in
backup file (he can't recognize that it's not complete source database).
So user would get "partial" database which might be useful. For example
it could be a way to move archive data, i.e. backup historic partitions
and restore them to historic database for some analytics.
It may also open an opportunity to create in-place restore for gbak. It
would restore to existing database, replacing partitions found there
with content of partitions found in backup file (would require unique
partition ID).
Certainly, using selective partition backup/restore must be paired with
proper database design and partitioning to make it work properly, but
it's certainly a nice tool for handling long-living databases and
historic data management.
best regards
Pavel Cisar
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