Re: Broken hint bits (freeze)

On Tue, Jun 20, 2017 at 7:05 PM, Sergey Burladyan <eshkinkot(at)gmail(dot)com> wrote:
> Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> writes:
>
>> On Tue, Jun 20, 2017 at 3:40 PM, Sergey Burladyan <eshkinkot(at)gmail(dot)com> wrote:
> I use pg 9.2 and "skipping restartpoint, already performed at" is from
> src/backend/access/transam/xlog.c:8643
> after this statement it return from CreateRestartPoint() and do not run
> 8687 CheckPointGuts(lastCheckPoint.redo, flags);
>

You are right, so it will skip restartpoint in such a case.

>> >> > Uh, as I understand it the rsync is going to copy the missing WAL file
>> >> > from the new master to the standby, right, and I think pg_controldata
>> >> > too, so it should be fine. Have you tested to see if it fails?
>> >
>> > It need old WAL files from old version for correct restore heap
>> > files. New WAL files from new version does not have this information.
>> >
>>
>> So in such a case can we run rsync once before pg_upgrade?
>
> I just copy last WAL from stopped old master into running old standby
> before it shutdown and wait till it replayed. After that standby can
> issue restartpoint at the same location as in stopped master.
>

Hmm. I think we need something that works with lesser effort because
not all users will be as knowledgeable as you are, so if they make any
mistakes in copying the file manually, it can lead to problems. How
about issuing a notification (XLogArchiveNotifySeg) in shutdown
checkpoint if archiving is enabled?

> I am not sure about rsync, in my production server I have for example
> 111 GB in pg_xlog and if I run rsync for pg_xlog it must send ~ 40GB
> of new WALs I think.
>

Isn't the difference between old and new is just the last WAL segment
file? What is the source of this difference?

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com