Re: [HACKERS] PG 10 release notes

On 2017-05-04 20:46:24 -0400, Bruce Momjian wrote:
> On Thu, May  4, 2017 at 05:09:40PM -0700, Andres Freund wrote:
> > > > 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.
> 
> I am getting tired of saying this.  When I am writing the release notes,
> I am trying to figure out how it affects our shipped code, and the only
> "decoding" I know of is test_decoding.

Then ask for input instead of saying uninformed stuff like "I didn't
think logical decoding was really more than a proof-of-concept".  That's
what people are complaining about, not that you're not
all-knowledgeable.  I agree with you - and wrote that previously - that
the specific change is not necessarily worthwhile to be mentioned on its
own, I don't see how that makes your various statements in this
subthread ok.


My message was this:
>     https://www.postgresql.org/message-id/a6d13cf7-fbf8-913c-2353-f149c6f95fdc%402ndquadrant.com
>     > 
>     >> 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.
> 
> Now, if the "encoding"

There's not really a "encoding" part of this. The decoding refers to
decoding the WAL into something externally usable.


> I assume it is this commit:

That, and
commit 24c5f1a103ce6656a5cb430d9a996c34e61ab2a5
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date:   2016-03-30 20:07:05 -0300
   Enable logical slots to follow timeline switches      When decoding from a logical slot, it's necessary for xlog
readingto be   able to read xlog from historical (i.e. not current) timelines;   otherwise, decoding fails after
failover,because the archives are in   the historical timeline.  This is required to make "failover logical   slots"
possible;it currently has no other use, although theoretically   it could be used by an extension that creates a slot
ona standby and   continues to replay from the slot when the standby is promoted.      This commit includes a module in
src/test/moduleswith functions to   manipulate the slots (which is not otherwise possible in SQL code) in   order to
enabletesting, and a new test in src/test/recovery to ensure   that the behavior is as expected.      Author: Craig
Ringer  Reviewed-By: Oleksii Kliukin, Andres Freund, Petr Jelínek