On Wed, May 20, 2009 at 2:53 PM, Chen, Dongdong (GE Healthcare)
<DongdongChen@ge.com> wrote:
In my application, when press button "Backup" in UI, it invokes pg_dump to backup the database. It may take few minutes for the whole process. If I want to pause the process, what should I do. And also how to resume the process? Can I pause while pg_restore?
I don't know if the following would be recommended, but did some research and it seems that one can use STOP and CONT signals on Linux/Unix to pause/continue a process. There are equivalent things you can do on NT based Windows too, for eg. by using ProcessExplorer's suspend/resume menu options for a process.
kill -STOP <pid>
kill -CONT <pid>
So, you have a choice of pausing/resuming the clients (like psql/pg_dump/pg_restore) or if you have access to the DB host, then you can pause/resume the backend process that is performing the dump/restore. I myself generally wouldn't recommend mucking with a backend process.
Although it seems safe, it does come with some implications if not excercised properly. If the process being paused has taken any DB level locks, you'll see contention because of those locks. You might also see long running '<IDLE> in transaction' session, which hinder in Vacuum process.
As I said, I am not sure if it would be recommended by experts, so would recommend waiting for someone else to respond to this approach.
Best regards,
--
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