Re: [HACKERS] PG 10 release notes

On 2017-05-04 19:56:21 -0400, Bruce Momjian wrote:
> On Mon, May  1, 2017 at 08:02:46AM -0400, Robert Haas wrote:
> > On Tue, Apr 25, 2017 at 11:01 AM, Bruce Momjian <bruce@momjian.us> wrote:
> > >> Or the ability of logical decoding to follow timeline switches.
> > >
> > > I didn't think logical decoding was really more than a proof-of-concept
> > > until now.
> > 
> > /me searches for jaw on floor.
> > 
> > It sounds like you don't understand how logical decoding works.  There
> > are plugins -- fairly widely used, I think -- like
> > https://github.com/confluentinc/bottledwater-pg and
> > https://github.com/eulerto/wal2json which use the in-core
> > infrastructure to do very nifty things, much like there are foreign
> > data wrappers other than postgres_fdw.  Even test_decoding is (perhaps
> > regrettably) being used to build production solutions.  The point is
> > that most of the logic is in core; test_decoding or bottlewater or
> > wal2json are just small plugins that tap into that infrastructure.
> > 
> > I would not in any way refer to logical decoding as being only a proof
> > of concept, even before logical replication.
> 
> The community ships a reliable logical _encoding_, and a test logical
> _decoding_.

Yes, so what?  What you said is "I didn't think logical decoding was
really more than a proof-of-concept until now", which is plainly wrong,
given I know a significant number of users using it in production.  Some
of them are well known & large enterprises, and it's used to enable
critical things.


On Mon, May  1, 2017 at 08:02:46AM -0400, Robert Haas wrote:
> Even test_decoding is (perhaps regrettably) being used to build production solutions.

E.g. to power amazon's data migration service (yes, that scares me).


> My point was that based on the text it is test_decoding that can do
> timeline switches, and is that significant enough to mention in the
> release notes?  Now, if it is that logical "encoding" now allows
> external logical decoding modules to handle timeline switches, that is
> different, but no one has said that yet.

The change has nothing to do with test_decoding.


Petr: The timeline change itself does, for the moment, not seem
particularly noteworthy to me - it's not really useful atm on its own?
To me it's more of infrastructure to add "logical decoding on standby"
next release?


> You can have all the emotional reactions you want.

Nice one.