> Robert Haas <robertmh...@gmail.com> writes: > > On Thu, Apr 30, 2015 at 5:21 PM, Kouhei Kaigai <kai...@ak.jp.nec.com> wrote: > >> I wanted to submit the v14 after the above items get clarified. > >> The attached patch (v14) includes all what you suggested in the previous > >> message. > > > Committed, after heavily working over the documentation, and with some > > more revisions to the comments as well. > > I've been trying to code-review this patch, because the documentation > seemed several bricks shy of a load, and I find myself entirely confused > by the fdw_ps_tlist and custom_ps_tlist fields. The names, along with > some of the comments, imply that these are just targetlists for the join > nodes; but if that is the case then we don't need them, because surely > scan.targetlist would serve the purpose. There is some other, utterly > uncommented, code in setrefs.c and ruleutils.c that suggests these fields > are supposed to serve a purpose more like IndexOnlyScan.indextlist; but > if that's what they are the comments are woefully inadequate/misleading, > and I'm really unsure that the associated code actually works. > Main-point of your concern is lack of documentation/comments to introduce how does the pseudo-scan targetlist works here, isn't it??
> Also, > if that is what they're for (ie, to allow the FDW to redefine the scan > tuple contents) it would likely be better to decouple that feature from > whether the plan node is for a simple scan or a join. > In this version, we don't intend FDW/CSP to redefine the contents of scan tuples, even though I want off-loads heavy targetlist calculation workloads to external computing resources in *the future version*. > The business about > resjunk columns in that list also seems a bit half baked, or at least > underdocumented. > I'll add source code comments to introduce how does it works any when does it have resjunk=true. It will be a bit too deep to be introduced in the SGML file. > I do not think that this should have gotten committed without an attendant > proof-of-concept patch to postgres_fdw, so that the logic could be tested. > Hanada-san is now working according to the comments from Robert. Overall design was already discussed in the upthread and the latest implementation follows the people's consensus. Thanks, -- NEC Business Creation Division / PG-Strom Project KaiGai Kohei <kai...@ak.jp.nec.com> -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
