Re: postgres_fdw join pushdown (was Re: Custom/Foreign-Join-APIs)

fdw_scan_tlist represents the output fetched from the foreign server and is not necessarily the output of ForeignScan. ForeignScan node's output is represented by tlist argument to.

1119     return make_foreignscan(tlist,
1120                             local_exprs,
1121                             scan_relid,
1122                             params_list,
1123                             fdw_private,
1124                             fdw_scan_tlist,
1125                             remote_exprs,
1126                             outer_plan);
 
This tlist is built using build_path_tlist() for all join plans. IIUC, all of them output the same targetlist. We don't need to make sure that targetlist match as long as we are using the targetlist passed in by create_scan_plan(). Do you have a counter example?