Re: Support for N synchronous standby servers - take 2

On Thu, Feb 11, 2016 at 5:40 PM, Michael Paquier
<michael.paquier@gmail.com> wrote:
> On Fri, Feb 12, 2016 at 2:56 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Fri, Feb 5, 2016 at 3:36 AM, Michael Paquier
>> <michael.paquier@gmail.com> wrote:
>>> So, here are some thoughts to make that more user-friendly. I think
>>> that the critical issue here is to properly flatten the meta data in
>>> the custom language and represent it properly in a new catalog,
>>> without messing up too much with the existing pg_stat_replication that
>>> people are now used to for 5 releases since 9.0.
>>
>> Putting the metadata in a catalog doesn't seem great because that only
>> can ever work on the master.  Maybe there's no need to configure this
>> on the slaves and therefore it's OK, but I feel nervous about putting
>> cluster configuration in catalogs.  Another reason for that is that if
>> synchronous replication is broken, then you need a way to change the
>> catalog, which involves committing a write transaction; there's a
>> danger that your efforts to do this will be tripped up by the broken
>> synchronous replication configuration.
>
> I was referring to a catalog view that parses the information related
> to groups of s_s_names in a flattened way to show each group sync
> status. Perhaps my words should have been clearer.

Ah.  Well, that's different, then.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company