On 2/22/19 7:10 PM, Robert Haas wrote:
On Fri, Feb 22, 2019 at 12:35 PM Fujii Masao <masao.fu...@gmail.com> wrote:
-1 for the removal. I think that there are still many users of an exclusive
backup API, and it's not so easy to migrate their backup scripts so that
only non-exclusive one is used because of the reason I wrote in another thread.
https://postgr.es/m/cahgqgwhukebkvexvfwnljmq2rzos_shymiect+kbn-cbpq5...@mail.gmail.com
Yeah, those are interesting points. Unfortunately, I think something
as simple as your proposed...
psql -c "SELECT pg_start_backup()"
rsync, cp, tar, storage backup, or something
psql -c "SELECT pg_stop_backup()"
...doesn't have much chance of being correct. If you aren't checking
whether pg_start_backup() throws an error, for example, you have got a
very failure-prone set-up. That being said, it's possible to fix that
problem using some shell logic, whereas the problem of keeping a
connection open for the duration of the backup from the shell is much
harder. I recently ran across a case where someone attempted it but
did not get the logic entirely right, with rather painful
consequences.
Now you might say that people should not write their own tools and
just use professionally produced ones. But I don't really agree with
that, and whatever we think people SHOULD do, there are in fact a lot
of people using their own tools.
FWIW +1 for not remove exclusive backup.
Maintain a connection during the backup is a hard pre-requisite. In my
previous jobs I already done custom scripts to perform backup by using
pre/post backup hook to control backup software: With vmware to do PITR
backup with VM snapshot or with another file backup tool which perform
block deduplication. I do not see where is the problem if you check
pg_start_backup()/pg_stop_backup() went well?
It will be annoying if after this removal, companies must change their
backup strategy by using specific postgres tools (pgbackrest, barman).
Regards,
