Re: What is the correct steps if tar process is killed during pg_start_backup() and pg_stop_backup()

Thank you for reply. This helps me a lot.
The only reason why I use pg_start_backup rather than pg_basebackup is
because the db system in my company is still under 8.3.
I think I would try to convince my chief to upgrate it.

Regards,

Z.H. Shih

2015-07-15 19:50 GMT+08:00 Matheus de Oliveira <matioli(dot)matheus(at)gmail(dot)com>:

>
> On Wed, Jul 15, 2015 at 6:10 AM, Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>
> wrote:
>
>> > Q2) What if I decide to re-tar again my data,
>> > should I need to invoke pg_stop_backup() first and perform
>> pg_start_backup() -> tar ->
>> > pg_stop_backup()?
>>
>> No, that is not necessary.
>>
>
> I'd say that although it is not necessary, it is a good practice. As you
> are going to do the copy all over again, better reduce the window required
> for recovery. If you don't call pg_stop_backup, the restore will consider
> the first needed WAL file to be the one returned by the call of
> pg_start_backup; if this call and the tar error are not very closer in time
> and you have a lot of activity in the system that generated many WAL files,
> then the restore will require more WAL files then it is actually necessary.
>
> Besides, if you are doing an script for this procedure, you'd better have
> the script handle the error and call the pg_stop_backup directly.
>
> At last, any reason for not using pg_basebackup in this case? I'd say it
> is preferred over pg_start_backup+tar+pg_stop_backup, and less error prone.
>
> Regards,
> --
> Matheus de Oliveira
>
>
>