Change the planner-to-executor API so that the planner tells the executor

which comparison operators to use for plan nodes involving tuple comparison
(Agg, Group, Unique, SetOp).  Formerly the executor looked up the default
equality operator for the datatype, which was really pretty shaky, since it's
possible that the data being fed to the node is sorted according to some
nondefault operator class that could have an incompatible idea of equality.
The planner knows what it has sorted by and therefore can provide the right
equality operator to use.  Also, this change moves a couple of catalog lookups
out of the executor and into the planner, which should help startup time for
pre-planned queries by some small amount.  Modify the planner to remove some
other cavalier assumptions about always being able to use the default
operators.  Also add "nulls first/last" info to the Plan node for a mergejoin
--- neither the executor nor the planner can cope yet, but at least the API is
in place.

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.360 2007/01/09 02:14:11 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.361 2007/01/10 18:06:02 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -439,6 +439,7 @@ static MergeJoin *
 _copyMergeJoin(MergeJoin *from)
 {
 	MergeJoin  *newnode = makeNode(MergeJoin);
+	int			numCols;
 
 	/*
 	 * copy node superclass fields
@@ -449,8 +450,10 @@ _copyMergeJoin(MergeJoin *from)
 	 * copy remainder of node
 	 */
 	COPY_NODE_FIELD(mergeclauses);
-	COPY_NODE_FIELD(mergefamilies);
-	COPY_NODE_FIELD(mergestrategies);
+	numCols = list_length(from->mergeclauses);
+	COPY_POINTER_FIELD(mergeFamilies, numCols * sizeof(Oid));
+	COPY_POINTER_FIELD(mergeStrategies, numCols * sizeof(int));
+	COPY_POINTER_FIELD(mergeNullsFirst, numCols * sizeof(bool));
 
 	return newnode;
 }
@@ -528,6 +531,7 @@ _copyGroup(Group *from)
 
 	COPY_SCALAR_FIELD(numCols);
 	COPY_POINTER_FIELD(grpColIdx, from->numCols * sizeof(AttrNumber));
+	COPY_POINTER_FIELD(grpOperators, from->numCols * sizeof(Oid));
 
 	return newnode;
 }
@@ -545,7 +549,10 @@ _copyAgg(Agg *from)
 	COPY_SCALAR_FIELD(aggstrategy);
 	COPY_SCALAR_FIELD(numCols);
 	if (from->numCols > 0)
+	{
 		COPY_POINTER_FIELD(grpColIdx, from->numCols * sizeof(AttrNumber));
+		COPY_POINTER_FIELD(grpOperators, from->numCols * sizeof(Oid));
+	}
 	COPY_SCALAR_FIELD(numGroups);
 
 	return newnode;
@@ -569,6 +576,7 @@ _copyUnique(Unique *from)
 	 */
 	COPY_SCALAR_FIELD(numCols);
 	COPY_POINTER_FIELD(uniqColIdx, from->numCols * sizeof(AttrNumber));
+	COPY_POINTER_FIELD(uniqOperators, from->numCols * sizeof(Oid));
 
 	return newnode;
 }
@@ -612,6 +620,7 @@ _copySetOp(SetOp *from)
 	COPY_SCALAR_FIELD(cmd);
 	COPY_SCALAR_FIELD(numCols);
 	COPY_POINTER_FIELD(dupColIdx, from->numCols * sizeof(AttrNumber));
+	COPY_POINTER_FIELD(dupOperators, from->numCols * sizeof(Oid));
 	COPY_SCALAR_FIELD(flagColIdx);
 
 	return newnode;
@@ -1356,6 +1365,7 @@ _copyInClauseInfo(InClauseInfo *from)
 	COPY_BITMAPSET_FIELD(lefthand);
 	COPY_BITMAPSET_FIELD(righthand);
 	COPY_NODE_FIELD(sub_targetlist);
+	COPY_NODE_FIELD(in_operators);
 
 	return newnode;
 }

src/backend/nodes/equalfuncs.c

@@ -18,7 +18,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.294 2007/01/09 02:14:12 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.295 2007/01/10 18:06:03 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -638,6 +638,7 @@ _equalInClauseInfo(InClauseInfo *a, InClauseInfo *b)
 	COMPARE_BITMAPSET_FIELD(lefthand);
 	COMPARE_BITMAPSET_FIELD(righthand);
 	COMPARE_NODE_FIELD(sub_targetlist);
+	COMPARE_NODE_FIELD(in_operators);
 
 	return true;
 }

src/backend/nodes/outfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.292 2007/01/09 02:14:12 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.293 2007/01/10 18:06:03 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -437,13 +437,28 @@ _outNestLoop(StringInfo str, NestLoop *node)
 static void
 _outMergeJoin(StringInfo str, MergeJoin *node)
 {
+	int			numCols;
+	int			i;
+
 	WRITE_NODE_TYPE("MERGEJOIN");
 
 	_outJoinPlanInfo(str, (Join *) node);
 
 	WRITE_NODE_FIELD(mergeclauses);
-	WRITE_NODE_FIELD(mergefamilies);
-	WRITE_NODE_FIELD(mergestrategies);
+
+	numCols = list_length(node->mergeclauses);
+
+	appendStringInfo(str, " :mergeFamilies");
+	for (i = 0; i < numCols; i++)
+		appendStringInfo(str, " %u", node->mergeFamilies[i]);
+
+	appendStringInfo(str, " :mergeStrategies");
+	for (i = 0; i < numCols; i++)
+		appendStringInfo(str, " %d", node->mergeStrategies[i]);
+
+	appendStringInfo(str, " :mergeNullsFirst");
+	for (i = 0; i < numCols; i++)
+		appendStringInfo(str, " %d", (int) node->mergeNullsFirst[i]);
 }
 
 static void
@@ -482,6 +497,10 @@ _outGroup(StringInfo str, Group *node)
 	appendStringInfo(str, " :grpColIdx");
 	for (i = 0; i < node->numCols; i++)
 		appendStringInfo(str, " %d", node->grpColIdx[i]);
+
+	appendStringInfo(str, " :grpOperators");
+	for (i = 0; i < node->numCols; i++)
+		appendStringInfo(str, " %u", node->grpOperators[i]);
 }
 
 static void
@@ -530,6 +549,10 @@ _outUnique(StringInfo str, Unique *node)
 	appendStringInfo(str, " :uniqColIdx");
 	for (i = 0; i < node->numCols; i++)
 		appendStringInfo(str, " %d", node->uniqColIdx[i]);
+
+	appendStringInfo(str, " :uniqOperators");
+	for (i = 0; i < node->numCols; i++)
+		appendStringInfo(str, " %u", node->uniqOperators[i]);
 }
 
 static void
@@ -548,6 +571,10 @@ _outSetOp(StringInfo str, SetOp *node)
 	for (i = 0; i < node->numCols; i++)
 		appendStringInfo(str, " %d", node->dupColIdx[i]);
 
+	appendStringInfo(str, " :dupOperators");
+	for (i = 0; i < node->numCols; i++)
+		appendStringInfo(str, " %d", node->dupOperators[i]);
+
 	WRITE_INT_FIELD(flagColIdx);
 }
 
@@ -1169,13 +1196,29 @@ _outNestPath(StringInfo str, NestPath *node)
 static void
 _outMergePath(StringInfo str, MergePath *node)
 {
+	int			numCols;
+	int			i;
+
 	WRITE_NODE_TYPE("MERGEPATH");
 
 	_outJoinPathInfo(str, (JoinPath *) node);
 
 	WRITE_NODE_FIELD(path_mergeclauses);
-	WRITE_NODE_FIELD(path_mergefamilies);
-	WRITE_NODE_FIELD(path_mergestrategies);
+
+	numCols = list_length(node->path_mergeclauses);
+
+	appendStringInfo(str, " :path_mergeFamilies");
+	for (i = 0; i < numCols; i++)
+		appendStringInfo(str, " %u", node->path_mergeFamilies[i]);
+
+	appendStringInfo(str, " :path_mergeStrategies");
+	for (i = 0; i < numCols; i++)
+		appendStringInfo(str, " %d", node->path_mergeStrategies[i]);
+
+	appendStringInfo(str, " :path_mergeNullsFirst");
+	for (i = 0; i < numCols; i++)
+		appendStringInfo(str, " %d", (int) node->path_mergeNullsFirst[i]);
+
 	WRITE_NODE_FIELD(outersortkeys);
 	WRITE_NODE_FIELD(innersortkeys);
 }
@@ -1325,6 +1368,7 @@ _outInClauseInfo(StringInfo str, InClauseInfo *node)
 	WRITE_BITMAPSET_FIELD(lefthand);
 	WRITE_BITMAPSET_FIELD(righthand);
 	WRITE_NODE_FIELD(sub_targetlist);
+	WRITE_NODE_FIELD(in_operators);
 }
 
 static void