Re: Update does not move row across foreign partitions in v11

On Fri, Mar 8, 2019 at 11:09 PM Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> wrote:
>
> On 2019-Mar-08, Amit Langote wrote:
>
> > diff --git a/doc/src/sgml/ref/update.sgml b/doc/src/sgml/ref/update.sgml
> > index 77430a586c..f5cf8eab85 100644
> > --- a/doc/src/sgml/ref/update.sgml
> > +++ b/doc/src/sgml/ref/update.sgml
> > @@ -291,9 +291,9 @@ UPDATE <replaceable class="parameter">count</replaceable>
> > concurrent <command>UPDATE</command> or <command>DELETE</command> on the
> > same row may miss this row. For details see the section
> > <xref linkend="ddl-partitioning-declarative-limitations"/>.
> > - Currently, rows cannot be moved from a partition that is a
> > - foreign table to some other partition, but they can be moved into a foreign
> > - table if the foreign data wrapper supports it.
> > + While rows can be moved from local partitions to a foreign-table partition
> > + partition (provided the foreign data wrapper supports tuple routing), they
> > + cannot be moved from a foreign-table partition to some other partition.
> > </para>
> > </refsect1>
>
> LGTM. Maybe I'd change "some other" to "another", but maybe on a
> different phase of the moon I'd leave it alone.

Done.

> I'm not sure about copying the same to ddl.sgml. Why is that needed?
> Update is not DDL.

Hmm, maybe because there's already a huge block of text describing
certain limitations of UPDATE row movement under concurrency?

Actually, I remember commenting *against* having that text in
ddl.sgml, but it got in there anyway.

> ddl.sgml does say this: "Partitions can also be
> foreign tables, although they have some limitations that normal tables
> do not; see CREATE FOREIGN TABLE for more information." which suggests
> that the limitation might need to be added to create_foreign_table.sgml.

Actually, that "more information" never got added to
create_foreign_table.sgml. There should've been some text about the
lack for tuple routing at least in PG 10's docs, but I guess that
never happened. Should we start now by listing this UPDATE row
movement limitation?

Anyway, I've only attached the patch for update.sgml this time.

Thanks,
Amit