Re: Horizontal scalability/sharding

On Mon, Aug 31, 2015 at 11:48 AM, Bruce Momjian <bruce@momjian.us> wrote:
> On Sun, Aug 30, 2015 at 10:08:06PM -0400, Bruce Momjian wrote:
>> On Mon, Aug 31, 2015 at 09:53:57AM +0900, Michael Paquier wrote:
>> >     Well, I have had many such discussions with XC/XL folks, and that was my
>> >     opinion.  I have seen almost no public discussion about this because the
>> >     idea had almost no chance of success.  If it was possible, someone would
>> >     have already suggested it on this list.
>> >
>> >
>> > Or perhaps people invested in this area had other obligations or lacked
>> > motivation and/or time to work to push up for things in core. That's not
>> > possible to know, and what is done is done.
>>
>> Well, I have talked to everyone privately about this, and concluded that
>> while horizontal scalability/sharding is useful, it is unlikely that the
>> code volume of something like XC or XL would be accepted into the
>> community, and frankly, now that we have FDWs, it is hard to imagine why
>> we would _not_ go in the FDW direction.
>
> Actually, there was hope that XC or XL would get popular enough that it
> would justify adding their code into community Postgres, but that never
> happened.

Forks are aimed to die without proper maintenance resources. Still,
for XC/XL, what does not help is the complication of the architecture
and SPOF management, particularly thinking with the GTM that was
something completely new and not well understood (there is a GTM
standby but this model is weak IMO and does not scale similarly to
what you get with standbys, and impacts the overall performance of the
cluster).
-- 
Michael