From db436adf761bd5cb7990745ceba2959ac4bfca7c Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 21 Aug 1999 03:49:17 +0000
Subject: Major revision of sort-node handling: push knowledge of query sort
 order down into planner, instead of handling it only at the very top level of
 the planner.  This fixes many things.  An explicit sort is now avoided if
 there is a cheaper alternative (typically an indexscan) not only for ORDER
 BY, but also for the internal sort of GROUP BY.  It works even when there is
 no other reason (such as a WHERE condition) to consider the indexscan.  It
 works for indexes on functions.  It works for indexes on functions,
 backwards.  It's just so cool...

CAUTION: I have changed the representation of SortClause nodes, therefore
THIS UPDATE BREAKS STORED RULES.  You will need to initdb.
---
 src/backend/nodes/copyfuncs.c | 49 +++++++++++++++++--------------------------
 1 file changed, 19 insertions(+), 30 deletions(-)

(limited to 'src/backend/nodes/copyfuncs.c')

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 99b1c39c7e6..4895be72379 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.91 1999/08/16 02:17:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.92 1999/08/21 03:48:57 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -456,12 +456,6 @@ _copyAgg(Agg *from)
 
 	CopyPlanFields((Plan *) from, (Plan *) newnode);
 
-	/*
-	 * Cannot copy agg list; it must be rebuilt to point to subnodes of
-	 * new node.
-	 */
-	set_agg_tlist_references(newnode);
-
 	return newnode;
 }
 
@@ -474,8 +468,8 @@ _copyGroupClause(GroupClause *from)
 {
 	GroupClause *newnode = makeNode(GroupClause);
 
-	newnode->grpOpoid = from->grpOpoid;
-	newnode->tleGroupref = from->tleGroupref;
+	newnode->tleSortGroupRef = from->tleSortGroupRef;
+	newnode->sortop = from->sortop;
 
 	return newnode;
 }
@@ -567,12 +561,11 @@ _copyResdom(Resdom *from)
 	newnode->resno = from->resno;
 	newnode->restype = from->restype;
 	newnode->restypmod = from->restypmod;
-
 	if (from->resname != NULL)
 		newnode->resname = pstrdup(from->resname);
+	newnode->ressortgroupref = from->ressortgroupref;
 	newnode->reskey = from->reskey;
 	newnode->reskeyop = from->reskeyop;
-	newnode->resgroupref = from->resgroupref;
 	newnode->resjunk = from->resjunk;
 
 	return newnode;
@@ -862,8 +855,8 @@ _copyAggref(Aggref *from)
 	newnode->basetype = from->basetype;
 	newnode->aggtype = from->aggtype;
 	Node_Copy(from, newnode, target);
-	newnode->aggno = from->aggno;
 	newnode->usenulls = from->usenulls;
+	newnode->aggno = from->aggno; /* probably not needed */
 
 	return newnode;
 }
@@ -1345,8 +1338,8 @@ _copySortClause(SortClause *from)
 {
 	SortClause *newnode = makeNode(SortClause);
 
-	Node_Copy(from, newnode, resdom);
-	newnode->opoid = from->opoid;
+	newnode->tleSortGroupRef = from->tleSortGroupRef;
+	newnode->sortop = from->sortop;
 
 	return newnode;
 }
@@ -1398,33 +1391,29 @@ _copyQuery(Query *from)
 	newnode->isBinary = from->isBinary;
 	newnode->isTemp = from->isTemp;
 	newnode->unionall = from->unionall;
-	if (from->uniqueFlag)
-		newnode->uniqueFlag = pstrdup(from->uniqueFlag);
-	Node_Copy(from, newnode, sortClause);
+	newnode->hasAggs = from->hasAggs;
+	newnode->hasSubLinks = from->hasSubLinks;
+
 	Node_Copy(from, newnode, rtable);
 	Node_Copy(from, newnode, targetList);
 	Node_Copy(from, newnode, qual);
+	Node_Copy(from, newnode, rowMark);
 
+	if (from->uniqueFlag)
+		newnode->uniqueFlag = pstrdup(from->uniqueFlag);
+	Node_Copy(from, newnode, sortClause);
 	Node_Copy(from, newnode, groupClause);
 	Node_Copy(from, newnode, havingQual);
 
-	newnode->hasAggs = from->hasAggs;
-	newnode->hasSubLinks = from->hasSubLinks;
-
-	if (from->unionClause)
-	{
-		List	   *ulist,
-				   *temp_list = NIL;
-
-		foreach(ulist, from->unionClause)
-			temp_list = lappend(temp_list, copyObject(lfirst(ulist)));
-		newnode->unionClause = temp_list;
-	}
+	/* why is intersectClause missing? */
+	Node_Copy(from, newnode, unionClause);
 
 	Node_Copy(from, newnode, limitOffset);
 	Node_Copy(from, newnode, limitCount);
 
-	Node_Copy(from, newnode, rowMark);
+	/* we do not copy the planner internal fields: base_rel_list,
+	 * join_rel_list, query_pathkeys.  Not entirely clear if this is right?
+	 */
 
 	return newnode;
 }
-- 
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