unused-targets-1.patch

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
new file mode 100644
index 34d4f40..298f5b5
*** a/src/backend/nodes/copyfuncs.c
--- b/src/backend/nodes/copyfuncs.c
*************** _copyTargetEntry(const TargetEntry *from
*** 1753,1758 ****
--- 1753,1759 ----
  	COPY_SCALAR_FIELD(resorigtbl);
  	COPY_SCALAR_FIELD(resorigcol);
  	COPY_SCALAR_FIELD(resjunk);
+ 	COPY_SCALAR_FIELD(resorderbyonly);
  
  	return newnode;
  }
diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c
new file mode 100644
index bb5cdae..65f7058
*** a/src/backend/nodes/makefuncs.c
--- b/src/backend/nodes/makefuncs.c
*************** makeTargetEntry(Expr *expr,
*** 230,235 ****
--- 230,236 ----
  	tle->resorigcol = 0;
  
  	tle->resjunk = resjunk;
+ 	tle->resorderbyonly = false;
  
  	return tle;
  }
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
new file mode 100644
index b61005f..96add12
*** a/src/backend/optimizer/plan/planner.c
--- b/src/backend/optimizer/plan/planner.c
*************** grouping_planner(PlannerInfo *root, doub
*** 1794,1799 ****
--- 1794,1826 ----
  														   limit_tuples);
  			current_pathkeys = root->sort_pathkeys;
  		}
+ 		else
+ 		{
+ 			/*
+ 			 * Plan come out in the right order, we can remove attributes which
+ 			 * are used only for ORDER BY clause because there is no need to
+ 			 * calculate them.
+ 			 */
+ 			ListCell *tl, *tl_prev, *tl_next;
+ 			tl_prev = NULL;
+ 			tl = list_head(result_plan->targetlist);
+ 			while (tl)
+ 			{
+ 				TargetEntry *tle = (TargetEntry *)lfirst(tl);
+ 				tl_next = lnext(tl);
+ 				if (tle->resorderbyonly && tle->resjunk)
+ 				{
+ 					result_plan->targetlist =
+ 						list_delete_cell(result_plan->targetlist, tl, tl_prev);
+ 				}
+ 				else
+ 				{
+ 					tl_prev = tl;
+ 				}
+ 
+ 				tl = tl_next;
+ 			}
+ 		}
  	}
  
  	/*
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
new file mode 100644
index ee40b55..842cf11
*** a/src/backend/parser/parse_clause.c
--- b/src/backend/parser/parse_clause.c
*************** findTargetlistEntrySQL99(ParseState *pst
*** 1501,1507 ****
--- 1501,1512 ----
  		texpr = strip_implicit_coercions((Node *) tle->expr);
  
  		if (equal(expr, texpr))
+ 		{
+ 			/* Update resorderbyonly flag */
+ 			if (exprKind != EXPR_KIND_ORDER_BY)
+ 				tle->resorderbyonly = false;
  			return tle;
+ 		}
  	}
  
  	/*
*************** findTargetlistEntrySQL99(ParseState *pst
*** 1512,1517 ****
--- 1517,1526 ----
  	target_result = transformTargetEntry(pstate, node, expr, exprKind,
  										 NULL, true);
  
+ 	/* Set resorderbyonly flag if needed */
+ 	if (exprKind == EXPR_KIND_ORDER_BY)
+ 		target_result->resorderbyonly = true;
+ 
  	*tlist = lappend(*tlist, target_result);
  
  	return target_result;
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
new file mode 100644
index cd4561d..129755e
*** a/src/include/nodes/primnodes.h
--- b/src/include/nodes/primnodes.h
*************** typedef struct TargetEntry
*** 1172,1177 ****
--- 1172,1178 ----
  	AttrNumber	resorigcol;		/* column's number in source table */
  	bool		resjunk;		/* set to true to eliminate the attribute from
  								 * final target list */
+ 	bool		resorderbyonly; /* attribute is used only in ORDER BY clause */
  } TargetEntry;
  
  
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
new file mode 100644
index 906a928..4e2e9fa
*** a/src/test/regress/expected/inherit.out
--- b/src/test/regress/expected/inherit.out
*************** explain (verbose, costs off) select * fr
*** 1213,1219 ****
                                 QUERY PLAN                               
  ------------------------------------------------------------------------
   Result
!    Output: matest0.id, matest0.name, ((1 - matest0.id))
     ->  Merge Append
           Sort Key: ((1 - matest0.id))
           ->  Index Scan using matest0i on public.matest0
--- 1213,1219 ----
                                 QUERY PLAN                               
  ------------------------------------------------------------------------
   Result
!    Output: matest0.id, matest0.name
     ->  Merge Append
           Sort Key: ((1 - matest0.id))
           ->  Index Scan using matest0i on public.matest0