On 2016/08/01 21:14, Etsuro Fujita wrote:
I noticed that the following note about direct modification via GetForeignUpperPaths in fdwhandler.sgml is a bit confusing. We have another approach using PlanDirectModify, so that should be reflected in the note as well. Please find attached a patch.<function>PlanForeignModify</> and the other callbacks described in <xref linkend="fdw-callbacks-update"> are designed around the assumption that the foreign relation will be scanned in the usual way and then individual row updates will be driven by a local <literal>ModifyTable</> plan node. This approach is necessary for the general case where an update requires reading local tables as well as foreign tables. However, if the operation could be executed entirely by the foreign server, the FDW could generate a path representing that and insert it into the <literal>UPPERREL_FINAL</> upper relation, where it would compete against the <literal>ModifyTable</> approach.
I'll add this to the upcoming CF. 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
