> Thanks for finding out what we oversight. > Here is still a problem because the new 'relids' field is not updated > on setrefs.c (scanrelid is incremented by rtoffset here). > It is easy to shift the bitmapset by rtoffset, however, I also would > like to see another approach. > > > > I just made it work for explain, but other parts still need work. Sorry about > that. If we follow INDEX_VAR, we should be able to get there. > I tried to modify your patch a bit as below: * add adjustment of bitmap fields on setrefs.c * add support on outfuncs.c and copyfuncs.c. * add bms_shift_members() in bitmapset.c
I think it is a reasonable enhancement, however, it is not tested with real-life code, like postgres_fdw. Hanada-san, could you add a feature to print name of foreign-tables which are involved in remote queries, on postgresExplainForeignScan()? ForeignScan->fdw_relids bitmap and ExplainState->rtable_names will tell you the joined foreign tables replaced by the (pseudo) foreign-scan. Soon, I'll update the interface patch also. > My idea adds 'List *fdw_sub_paths' field in ForeignPath to inform > planner underlying foreign-scan paths (with scanrelid > 0). > The create_foreignscan_plan() will call create_plan_recurse() to > construct plan nodes based on the path nodes being attached. > Even though these foreign-scan nodes are not actually executed, > setrefs.c can update scanrelid in usual way and ExplainPreScanNode > does not need to take exceptional handling on Foreign/CustomScan > nodes. > In addition, it allows to keep information about underlying foreign > table scan, even if planner will need some other information in the > future version (not only relids). > > How about your thought? > > > > I am not sure about keeping planner nodes, which are not turned into execution > nodes. There's no precedence for that in current code. It could be risky. > Indeed, it is a fair enough opinion. At this moment, no other code makes plan node but shall not be executed actually. Please forget above idea. Thanks, -- NEC OSS Promotion Center / PG-Strom Project KaiGai Kohei <kai...@ak.jp.nec.com>
add_fdw_custom_relids.patch
Description: add_fdw_custom_relids.patch
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