On 2016/05/27 8:49, Michael Paquier wrote:
On Thu, May 26, 2016 at 4:25 AM, Etsuro Fujita <fujita.ets...@lab.ntt.co.jp> wrote:
Honestly, I didn't have any idea for executing such an insert efficiently, but I was thinking to execute an insert into a foreign table efficiently, by sending the whole insert to the remote server, if possible. For example, if the insert is of the form: INSERT INTO foreign_table(a,b,c) VALUES (1, 2, 3), (4, 5, 6) or INSERT INTO foreign_table(a,b,c) SELECT a,b,c FROM foreign_table2 where foreign_table and foreign_table2 belong to the same foreign server, then we could send the whole insert to the remote server. Wouldn't that make sense?
Query strings have a limited length, and this assumption is true for many code paths in the backend code, so doing that with a long string would introduce more pain in the logic than anything else, as this would become more data type sensitive.
That's a good point, but the basic idea is to send the local query almost-as-is to the remote server if possible. For example, if the local query is "INSERT INTO foreign_table(a,b,c) VALUES (1, 2, 3), (4, 5, 6)", send the remote query "INSERT INTO remote_table(a,b,c) VALUES (1, 2, 3), (4, 5, 6)" to the remote server where remote_table is the table name for the foreign table on the remote server. So, wouldn't the query string length be a problem in many cases? Maybe I'm missing something, though.
Best regards, Etsuro Fujita -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
