Re: Switching timeline over streaming replication

On 17 December 2012 12:07, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>wrote:

> On 15.12.2012 01:09, Josh Berkus wrote:
>
>> Tested this on yesterday's snapshot. Worked great.
>>
>
> Thanks for the testing!
>
>
> Now I wanna test a chain of cascading replicas ... how far can we chain
>> these?
>>
>
> There's no limit in theory. I tested with one master and two chained
> standbys myself. Give it a shot, I'm curious to hear how it works with a
> chain of a hundred standbys ;-).
>

I just set up 120 chained standbys, and for some reason I'm seeing these
errors:

LOG: replication terminated by primary server
DETAIL: End of WAL reached on timeline 1
LOG: record with zero length at 0/301EC10
LOG: fetching timeline history file for timeline 2 from primary server
LOG: restarted WAL streaming at 0/3000000 on timeline 1
LOG: replication terminated by primary server
DETAIL: End of WAL reached on timeline 1
LOG: new target timeline is 2
LOG: restarted WAL streaming at 0/3000000 on timeline 2
LOG: replication terminated by primary server
DETAIL: End of WAL reached on timeline 2
FATAL: error reading result of streaming command: ERROR: requested WAL
segment 000000020000000000000003 has already been removed

ERROR: requested WAL segment 000000020000000000000003 has already been
removed
LOG: started streaming WAL from primary at 0/3000000 on timeline 2
ERROR: requested WAL segment 000000020000000000000003 has already been
removed

The "End of WAL reached on timeline 2" appears on all standbys except the
one streaming directly from the primary.

However, changes continue to cascade to all standbys right to the end of
the chain (it takes several minutes to propagate however).

--
Thom