Re: Support for pg_receivexlog --post-segment command

On Fri, Jan 6, 2017 at 2:30 PM, David Steele <david(at)pgmasters(dot)net> wrote:

> On 1/6/17 8:09 AM, Feike Steenbergen wrote:
>
>> On 6 January 2017 at 13:50, Magnus Hagander <magnus(at)hagander(dot)net
>> <mailto:magnus(at)hagander(dot)net>> wrote:
>>
>>> I think we're better off clearly documenting that we don't care about
>>>
>> it. And basically let the external command be responsible for that part.
>>
>> So for example, your typical backup manager would listen to this
>>>
>> signal or whatever to react quickly. But it would *also* have some sort
>> of fallback. For example, whenever it's triggered it also checks if
>> there are any previous segments it missed (this would also cover the
>> startup sequence).
>>
>
> I'm fine with the backup manager doing all the work of keeping track of
> what has been compressed, moved to archive, etc. No need to reinvent the
> wheel here.
>
> For my part I still prefer an actual command to be executed so it will
> start/restart the archiver if it is not already running or died. This
> reduces the number of processes that I need to ensure are running.
>
> If the consensus is that a signal is better then I'll make that work. I
> will say this raises the bar on what is required to write a good archive
> command and we already know it is quite a difficult task.

I like the idea of a command as well, for flexibility. If you want a
signal, you can write a trivial command that sends the signal... Maximum
flexibility, as long as we don't create a lot of caveats for users.

--
Magnus Hagander
Me: http://www.hagander.net/
Work: http://www.redpill-linpro.com/