On 8.11.2013 16:13, Albe Laurenz wrote: > Tom Lane wrote: >> Albe Laurenz <laurenz.a...@wien.gv.at> writes: >>> What I would like to do is add a custom resjunk column (e.g. a >>> bytea) in AddForeignUpdateTargets that carries a row identifier >>> from the scan state to the modify state. Would that be possible? >>> Can I have anything else than a Var in a resjunk column? >> >> [ thinks for awhile... ] Hm. In principle you can put any >> expression you want into the tlist during AddForeignUpdateTargets. >> However, if it's not a Var then the planner won't understand that >> it's something that needs to be supplied by the table scan, so >> things won't work right in any but the most trivial cases (maybe >> not even then :-(). >> >> What I'd try is creating a Var that has the attno of ctid (ie, >> SelfItemPointerAttributeNumber) but the datatype you want, ie >> bytea. This won't match what the catalogs say your table's ctid is, >> but I think that nothing will care much about that. >> >> It's definitely an area that could use more work. IIRC we'd >> discussed providing some way for an FDW to specify the type of the >> ctid column for its tables, but we didn't do anything about it in >> 9.3. > > Thanks a lot, I will try that.
Hi Laurenz, have you found a way to pass data types other than TID as a resjunk column? I'm trying to solve almost the same thing (pass INT8 instead of TID), but I got stuck. Adding a custom Var with INT8OID instead of TIDOID seems to work fine, but I've found no way to populate this in IterateForeignScan :-( regards Tomas -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
