Thread: pgsql: Update dblink extension for parallel query.

Update dblink extension for parallel query.

Almost all functions provided by this extension are PARALLEL
RESTRICTED.  Mostly, that's because the leader's TCP connections won't
be shared with the workers, but in some cases like dblink_get_pkey
it's because they obtain locks which might be released early if taken
within a parallel worker.  dblink_fdw_validator probably can't be used
in a query anyway, but there would be no problem from the point of
view of parallel query if it were, so it's PARALLEL SAFE.

Andreas Karlsson

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/20eb2731b7775f3381939d2667b6aa8ba62ab2c5

Modified Files
--------------
contrib/dblink/Makefile             |   3 +-
contrib/dblink/dblink--1.1--1.2.sql |  46 +++++++
contrib/dblink/dblink--1.1.sql      | 235 ------------------------------------
contrib/dblink/dblink--1.2.sql      | 235 ++++++++++++++++++++++++++++++++++++
contrib/dblink/dblink.control       |   2 +-
5 files changed, 284 insertions(+), 237 deletions(-)

Robert Haas <rhaas@postgresql.org> writes:
> Update dblink extension for parallel query.

Buildfarm results from mandrill and lapwing say that these markings
weren't thought through carefully enough.  Or else we've got yet another
hole in the logic that's supposed to prevent PARALLEL RESTRICTED functions
from being sent to workers.

            regards, tom lane

On 06/18/2016 12:15 AM, Tom Lane wrote:
> Robert Haas <rhaas@postgresql.org> writes:
>> Update dblink extension for parallel query.
>
> Buildfarm results from mandrill and lapwing say that these markings
> weren't thought through carefully enough.  Or else we've got yet another
> hole in the logic that's supposed to prevent PARALLEL RESTRICTED functions
> from being sent to workers.

Thanks for fixing this bug. I did not think of temporary relations when
i read those functions.

Andreas