Restructure handling of inheritance queries so that they work with outer

joins, and clean things up a good deal at the same time.  Append plan node
no longer hacks on rangetable at runtime --- instead, all child tables are
given their own RT entries during planning.  Concept of multiple target
tables pushed up into execMain, replacing bug-prone implementation within
nodeAppend.  Planner now supports generating Append plans for inheritance
sets either at the top of the plan (the old way) or at the bottom.  Expanding
at the bottom is appropriate for tables used as sources, since they may
appear inside an outer join; but we must still expand at the top when the
target of an UPDATE or DELETE is an inheritance set, because we actually need
a different targetlist and junkfilter for each target table in that case.
Fortunately a target table can't be inside an outer join...  Bizarre mutual
recursion between union_planner and prepunion.c is gone --- in fact,
union_planner doesn't really have much to do with union queries anymore,
so I renamed it grouping_planner.

src/backend/nodes/readfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.99 2000/10/22 22:14:54 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.100 2000/11/12 00:36:57 tgl Exp $
  *
  * NOTES
  *	  Most of the read functions for plan nodes are tested. (In fact, they
@@ -150,6 +150,9 @@ _readQuery(void)
 	token = lsptok(NULL, &length);		/* skip :setOperations */
 	local_node->setOperations = nodeRead(true);
 
+	token = lsptok(NULL, &length);		/* skip :resultRelations */
+	local_node->resultRelations = toIntList(nodeRead(true));
+
 	return local_node;
 }
 
@@ -260,17 +263,6 @@ _getPlan(Plan *node)
 	token = lsptok(NULL, &length);		/* get the plan_width */
 	node->plan_width = atoi(token);
 
-	token = lsptok(NULL, &length);		/* eat the :state stuff */
-	token = lsptok(NULL, &length);		/* now get the state */
-
-	if (length == 0)
-		node->state = (EState *) NULL;
-	else
-	{							/* Disgusting hack until I figure out what
-								 * to do here */
-		node->state = (EState *) !NULL;
-	}
-
 	token = lsptok(NULL, &length);		/* eat :qptargetlist */
 	node->targetlist = nodeRead(true);
 
@@ -283,6 +275,8 @@ _getPlan(Plan *node)
 	token = lsptok(NULL, &length);		/* eat :righttree */
 	node->righttree = (Plan *) nodeRead(true);
 
+	node->state = (EState *) NULL;		/* never read in */
+
 	return;
 }
 
@@ -348,12 +342,9 @@ _readAppend(void)
 	token = lsptok(NULL, &length);		/* eat :appendplans */
 	local_node->appendplans = nodeRead(true);	/* now read it */
 
-	token = lsptok(NULL, &length);		/* eat :inheritrelid */
-	token = lsptok(NULL, &length);		/* get inheritrelid */
-	local_node->inheritrelid = strtoul(token, NULL, 10);
-
-	token = lsptok(NULL, &length);		/* eat :inheritrtable */
-	local_node->inheritrtable = nodeRead(true); /* now read it */
+	token = lsptok(NULL, &length);		/* eat :isTarget */
+	token = lsptok(NULL, &length);		/* get isTarget */
+	local_node->isTarget = (token[0] == 't') ? true : false;
 
 	return local_node;
 }
@@ -1297,43 +1288,6 @@ _readJoinExpr(void)
 	return local_node;
 }
 
-/*
- *	Stuff from execnodes.h
- */
-
-/* ----------------
- *		_readEState
- *
- *	EState is a subclass of Node.
- * ----------------
- */
-static EState *
-_readEState(void)
-{
-	EState	   *local_node;
-	char	   *token;
-	int			length;
-
-	local_node = makeNode(EState);
-
-	token = lsptok(NULL, &length);		/* get :direction */
-	token = lsptok(NULL, &length);		/* now read it */
-
-	local_node->es_direction = atoi(token);
-
-	token = lsptok(NULL, &length);		/* get :range_table */
-
-	local_node->es_range_table = nodeRead(true);		/* now read it */
-
-	token = lsptok(NULL, &length);		/* get :result_relation_info */
-	token = lsptok(NULL, &length);		/* get @ */
-	token = lsptok(NULL, &length);		/* now read it */
-
-	sscanf(token, "%x", (unsigned int *) &local_node->es_result_relation_info);
-
-	return local_node;
-}
-
 /*
  *	Stuff from relation.h
  */
@@ -1639,6 +1593,42 @@ _readTidPath(void)
 	return local_node;
 }
 
+/* ----------------
+ *		_readAppendPath
+ *
+ *	AppendPath is a subclass of Path.
+ * ----------------
+ */
+static AppendPath *
+_readAppendPath(void)
+{
+	AppendPath *local_node;
+	char	   *token;
+	int			length;
+
+	local_node = makeNode(AppendPath);
+
+	token = lsptok(NULL, &length);		/* get :pathtype */
+	token = lsptok(NULL, &length);		/* now read it */
+	local_node->path.pathtype = atol(token);
+
+	token = lsptok(NULL, &length);		/* get :startup_cost */
+	token = lsptok(NULL, &length);		/* now read it */
+	local_node->path.startup_cost = (Cost) atof(token);
+
+	token = lsptok(NULL, &length);		/* get :total_cost */
+	token = lsptok(NULL, &length);		/* now read it */
+	local_node->path.total_cost = (Cost) atof(token);
+
+	token = lsptok(NULL, &length);		/* get :pathkeys */
+	local_node->path.pathkeys = nodeRead(true); /* now read it */
+
+	token = lsptok(NULL, &length);		/* get :subpaths */
+	local_node->subpaths = nodeRead(true);		/* now read it */
+
+	return local_node;
+}
+
 /* ----------------
  *		_readNestPath
  *
@@ -1984,8 +1974,6 @@ parsePlanString(void)
 		return_value = _readOper();
 	else if (length == 5 && strncmp(token, "PARAM", length) == 0)
 		return_value = _readParam();
-	else if (length == 6 && strncmp(token, "ESTATE", length) == 0)
-		return_value = _readEState();
 	else if (length == 10 && strncmp(token, "RELOPTINFO", length) == 0)
 		return_value = _readRelOptInfo();
 	else if (length == 11 && strncmp(token, "TARGETENTRY", length) == 0)
@@ -1998,6 +1986,8 @@ parsePlanString(void)
 		return_value = _readIndexPath();
 	else if (length == 7 && strncmp(token, "TIDPATH", length) == 0)
 		return_value = _readTidPath();
+	else if (length == 10 && strncmp(token, "APPENDPATH", length) == 0)
+		return_value = _readAppendPath();
 	else if (length == 8 && strncmp(token, "NESTPATH", length) == 0)
 		return_value = _readNestPath();
 	else if (length == 9 && strncmp(token, "MERGEPATH", length) == 0)