Re: Support for N synchronous standby servers - take 2

On 2015-07-07 AM 02:56, Josh Berkus wrote:
>
> Re: group labels: I see a lot of value in being able to add names to
> quorum groups. Think about how this will be represented in system
> views; it will be difficult to show sync status of any quorum group in
> any meaningful way if the group has no label, and any system-assigned
> label would change unpredictably from the user's perspective.
>
> To give a JSON example, let's take the case of needing to sync to two of
> the servers in either London or NC:
>
> '{ "remotes" : { "london_servers" : { "quorum" : 2, "servers" : [
> "london1", "london2", "london3" ] }, "nc_servers" : { "quorum" : 1,
> "servers" [ "nc1", "nc2" ] } }'
>

What if we write the above as:

remotes-1 (london_servers-2 [london1, london2, london3], nc_servers-1 [nc1, nc2])

That requires only slightly altering the proposed format, that is prepend sync
group label string to the quorum number. The monitoring view can be made to
internally generate JSON output (if needed) from it. It does not seem very
ALTER SYSTEM SET friendly but there are trade-offs either way.

Just my 2c.

Thanks,
Amit