Re: PG 13 release notes, first draft - Mailing list pgsql-hackers

On Fri, May  8, 2020 at 12:32:16AM +0900, Amit Langote wrote:
> On Thu, May 7, 2020 at 9:48 PM Bruce Momjian <bruce@momjian.us> wrote:
> > On Thu, May  7, 2020 at 12:06:33AM +0900, Amit Langote wrote:
> > > +Author: Etsuro Fujita <efujita@postgresql.org>
> > > +2020-04-08 [c8434d64c] Allow partitionwise joins in more cases.
> > > +Author: Tom Lane <tgl@sss.pgh.pa.us>
> > > +2020-04-07 [981643dcd] Allow partitionwise join to handle nested FULL JOIN USIN
> > > +-->
> > > +
> > > +<para>
> > > +Allow partitionwise joins to happen in more cases (Ashutosh Bapat,
> > > Etsuro Fujita, Amit Langote)
> > > +</para>
> > >
> > > Maybe it would be better to break this into two items, because while
> > > c8434d64c is significant new functionality that I only contributed a
> > > few review comments towards, 981643dcd is relatively minor surgery of
> >
> > What text would we use for the new item?  I thought FULL JOIN was just
> > another case that matched the description I had.
> 
> c8434d64c implements a new feature whereby, to use partitionwise join,
> partition bounds of the tables being joined no longer have to match
> exactly.  I think it might be better to mention this explicitly
> because it enables partitionwise joins to be used in more partitioning
> setups.

Well, the text says:

    Allow partitionwise joins to happen in more cases (Ashutosh Bapat,
    Etsuro Fujita, Amit Langote, Tom Lane)

Isn't that what you just said?  I just added this paragraph:

    For example, partitionwise joins can now happen between partitioned
    tables where the ancestors do not exactly match.

Does that help?

> 981643dcd fixes things so that 3-way and higher FULL JOINs can now be
> performed partitionwise.  I am okay with even omitting this if it
> doesn't sound big enough to be its own item.
> 
> > I think trying to put this all into one item is too complex, but I did
> > merge two of the items together, so we have two items now:
> >
> >         <listitem>
> >         <!--
> >         Author: Peter Eisentraut <peter@eisentraut.org>
> >         2020-03-10 [17b9e7f9f] Support adding partitioned tables to publication
> >         Author: Peter Eisentraut <peter@eisentraut.org>
> >         2020-04-08 [83fd4532a] Allow publishing partition changes via ancestors
> >         -->
> >
> >         <para>
> >         Allow partitioned tables to be replicated via publications (Amit Langote)
> >         </para>
> >
> >         <para>
> >         Previously, partitions had to be replicated individually.  Now
> >         partitioned tables can be published explicitly causing all partitions
> >         to be automatically published.  Addition/removal of partitions from
> >         partitioned tables are automatically added/removed on subscribers.
> >         The CREATE PUBLICATION option publish_via_partition_root controls whether
> >         partitioned tables are published as themselves or their ancestors.
> >         </para>
> 
> Thanks.  Sounds good except I think the last sentence should read:
> 
> ...controls whether partition changes are published as their own or as
> their ancestor's.

OK, done.

> >         </listitem>
> >
> >         <listitem>
> >         <!--
> >         Author: Peter Eisentraut <peter@eisentraut.org>
> >         2020-04-06 [f1ac27bfd] Add logical replication support to replicate into partit
> >         -->
> >
> >         <para>
> >         Allow non-partitioned tables to be logically replicated to subscribers
> >         that receive the rows into partitioned tables (Amit Langote)
> >         </para>
> 
> Hmm, why it make it sound like this works only if the source table is
> non-partitioned?  The source table can be anything, a regular
> non-partitioned table, or a partitioned one.

Well, we already covered the publish partitioned case in the above item.

> How about:
> 
> Allow logical replication into partitioned tables on subscribers
> 
> Previously, it was allowed only into regular [ non-partitioned ] tables.

OK, I used this wording:

    Allow logical replication into partitioned tables on subscribers (Amit
    Langote)
    
    Previously, subscribers could only receive rows into non-partitioned
    tables.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +