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  1. In postgres_fdw, don't try to ship MULTIEXPR updates to remote server.

  1. Segfault on updating foreign table

    Lukáš Sobotka <sobotka.luk@gmail.com> — 2020-01-26T07:00:00Z

    Hi there,

I tried to synchronize two tables on different databases using foreign data
wrapper. I executed update of foreign table with sub-query selection from
local table. As the result I got segmentation fault. General query:
UPDATE foreign_table SET (col) = (
    SELECT col
        FROM local_table
        WHERE foreign_table.id = local_table.id
);

I am not looking for working or better solution, I just want let you know
about this. I think the query is according documentation and segfault is
not suitable result. If somebody could check it I would be grateful.

For reproducer or log see attachments.
Tested on Ubuntu 18.04.3 LTS with PG12: PostgreSQL 12.1 (Ubuntu
12.1-1.pgdg18.04+1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
7.4.0-1ubuntu1~18.04.1) 7.4.0, 64-bit

Thanks for your time.

Best regards,
Lukas

  2. Re: Segfault on updating foreign table

    Tom Lane <tgl@sss.pgh.pa.us> — 2020-01-26T18:26:33Z

    =?UTF-8?B?THVrw6HFoSBTb2JvdGth?= <sobotka.luk@gmail.com> writes:
> I tried to synchronize two tables on different databases using foreign data
> wrapper. I executed update of foreign table with sub-query selection from
> local table. As the result I got segmentation fault. General query:
> UPDATE foreign_table SET (col) = (
>     SELECT col
>         FROM local_table
>         WHERE foreign_table.id = local_table.id
> );

Yup, that's a bug.  Will fix, thanks for the report!

			regards, tom lane