Re: Option to dump foreign data in pg_dump

Can you have a look at dump with parallel option. Parallel option will
take a lock on table while invoking lockTableForWorker. May be this is
not required for foreign tables.
Thoughts?
I tried with -j and found no issue. I guess that the foreign table needs locking anyway to prevent anyone to modify it while is being dumped.

Cheers,

Luis M Carril
________________________________
From: vignesh C <vignesh21@gmail.com>
Sent: Tuesday, January 14, 2020 1:48 AM
To: Luis Carril <luis.carril@swarm64.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>; Daniel Gustafsson <daniel@yesql.se>; Laurenz Albe <laurenz.albe@cybertec.at>; PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Option to dump foreign data in pg_dump

On Fri, Nov 29, 2019 at 2:10 PM Luis Carril <luis.carril@swarm64.com> wrote:
>
> Luis,
>
> It seems you've got enough support for this concept, so let's move
> forward with this patch.  There are some comments from Tom about the
> patch; would you like to send an updated version perhaps?
>
> Thanks
>
> Hi,
>
>  I've attached a new version (v6) removing the superfluous JOIN that Tom identified, and not collecting the oids (avoiding the query) if the option is not used at all.
>
> About the testing issues that Tom mentioned:
> I do not see how can we have a pure SQL dummy FDW that tests the functionality. Because the only way to identify if the data of a foreign table for the chosen server is dumped is if the COPY statement appears in the output, but if the C callbacks of the FDW are not implemented, then the SELECT that dumps the data to generate the COPY cannot be executed.
> Also, to test that the include option chooses only the data of the  specified foreign servers we would need some negative testing, i.e. that the COPY statement for the non-desired table does not appear. But I do not find these kind of tests in the test suite, even for other selective options like --table or --exclude-schema.
>

Can you have a look at dump with parallel option. Parallel option will
take a lock on table while invoking lockTableForWorker. May be this is
not required for foreign tables.
Thoughts?

Regards,
Vignesh
EnterpriseDB: http://www.enterprisedb.com