Message-ID: <5CA1A94E.1070002@lab.ntt.co.jp>
Date: Mon, 01 Apr 2019 15:01:50 +0900
From: Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>
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Subject: Re: BUG #15724: Can't create foreign table as partition
References: <21389.1553868091@sss.pgh.pa.us>
 <20190329141050.GA22336@alvherre.pgsql>
 <1553869152.858391073.5f8m3n0x@frv53.fwdcdn.com>
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To: Stepan Yankevych <stepya@ukr.net>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>,
        pgsql-bugs@lists.postgresql.org
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(2019/03/29 23:21), Stepan Yankevych wrote:
> I think we need at least to mention it in the doc
> https://www.postgresql.org/docs/11/ddl-partitioning.html
>
>> > Partitions can also be foreign tables, although they have some
> limitations that normal tables do not; see CREATE FOREIGN TABLE
> <https://www.postgresql.org/docs/11/sql-createforeigntable.html>for more
> information
> For example
> Partitions can also be foreign tables*only in case main table is non
> indexed and doesn't contain PK,*although they have some limitations that
> normal tables do not; see CREATE FOREIGN TABLE
> <https://www.postgresql.org/docs/11/sql-createforeigntable.html>for more
> information

+1 for adding such notes, but I'm not sure if it's a good idea to put it 
there because I think that would make the introductory documentation a 
bit verbose.  How about adding it to the reference pages of CREATE 
FOREIGN TABLE and ALTER TABLE like the attached?

Best regards,
Etsuro Fujita

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*** a/doc/src/sgml/ref/alter_table.sgml
--- b/doc/src/sgml/ref/alter_table.sgml
***************
*** 842,847 **** WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
--- 842,851 ----
        one will be created in the attached table; or, if an equivalent
        index already exists, will be attached to the target table's index,
        as if <command>ALTER INDEX ATTACH PARTITION</command> had been executed.
+       Note that if the existing table is a foreign table, it is currently not
+       allowed to attach the table as a partition of the target table if there
+       are indexes on the target table.  (See also
+       <xref linkend="sql-createtable"/>.)
       </para>
  
       <para>
*** a/doc/src/sgml/ref/create_foreign_table.sgml
--- b/doc/src/sgml/ref/create_foreign_table.sgml
***************
*** 169,174 **** CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ]
--- 169,178 ----
        the given parent table with specified partition bound values.
        See the similar form of
        <xref linkend="sql-createtable"/> for more details.
+       Note that it is currently not allowed to create the foreign table as a
+       partition of the parent table if there are indexes on the parent table.
+       (See also
+       <link linkend="sql-altertable"><command>ALTER TABLE ATTACH PARTITION</command></link>.)
       </para>
      </listitem>
     </varlistentry>

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