per-eclass-canon-pathkeys.patch

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index ee2aeb0..7a12c47 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -1595,7 +1595,6 @@ _outPlannerInfo(StringInfo str, PlannerInfo *node)
 	WRITE_NODE_FIELD(init_plans);
 	WRITE_NODE_FIELD(cte_plan_ids);
 	WRITE_NODE_FIELD(eq_classes);
-	WRITE_NODE_FIELD(canon_pathkeys);
 	WRITE_NODE_FIELD(left_join_clauses);
 	WRITE_NODE_FIELD(right_join_clauses);
 	WRITE_NODE_FIELD(full_join_clauses);
@@ -1692,6 +1691,7 @@ _outEquivalenceClass(StringInfo str, EquivalenceClass *node)
 	WRITE_BOOL_FIELD(ec_below_outer_join);
 	WRITE_BOOL_FIELD(ec_broken);
 	WRITE_UINT_FIELD(ec_sortref);
+	WRITE_NODE_FIELD(ec_canon_pathkeys);
 }
 
 static void
diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c
index 643d57a..d5e5c42 100644
--- a/src/backend/optimizer/path/pathkeys.c
+++ b/src/backend/optimizer/path/pathkeys.c
@@ -93,9 +93,10 @@ make_canonical_pathkey(PlannerInfo *root,
 	while (eclass->ec_merged)
 		eclass = eclass->ec_merged;
 
-	foreach(lc, root->canon_pathkeys)
+	foreach(lc, eclass->ec_canon_pathkeys)
 	{
 		pk = (PathKey *) lfirst(lc);
+		Assert(eclass == pk->pk_eclass);
 		if (eclass == pk->pk_eclass &&
 			opfamily == pk->pk_opfamily &&
 			strategy == pk->pk_strategy &&
@@ -110,7 +111,7 @@ make_canonical_pathkey(PlannerInfo *root,
 	oldcontext = MemoryContextSwitchTo(root->planner_cxt);
 
 	pk = makePathKey(eclass, opfamily, strategy, nulls_first);
-	root->canon_pathkeys = lappend(root->canon_pathkeys, pk);
+	eclass->ec_canon_pathkeys = lappend(eclass->ec_canon_pathkeys, pk);
 
 	MemoryContextSwitchTo(oldcontext);
 
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c
index fd4c6f5..5f8f817 100644
--- a/src/backend/optimizer/plan/planmain.c
+++ b/src/backend/optimizer/plan/planmain.c
@@ -117,7 +117,10 @@ query_planner(PlannerInfo *root, List *tlist,
 		 * We still are required to canonicalize any pathkeys, in case it's
 		 * something like "SELECT 2+2 ORDER BY 1".
 		 */
+/* XXX: Same as below */
+#if 0
 		root->canon_pathkeys = NIL;
+#endif
 		root->query_pathkeys = canonicalize_pathkeys(root,
 													 root->query_pathkeys);
 		root->group_pathkeys = canonicalize_pathkeys(root,
@@ -145,7 +148,13 @@ query_planner(PlannerInfo *root, List *tlist,
 	root->join_rel_hash = NULL;
 	root->join_rel_level = NULL;
 	root->join_cur_level = 0;
-	root->canon_pathkeys = NIL;
+/* XXX
+ * Do we need to reset something here? This is just initializing otherwise
+ * uninitialized fields, right?
+ */
+#if 0
+		root->canon_pathkeys = NIL;
+#endif
 	root->left_join_clauses = NIL;
 	root->right_join_clauses = NIL;
 	root->full_join_clauses = NIL;
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 6e3d0f3..c959708 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -160,8 +160,6 @@ typedef struct PlannerInfo
 
 	List	   *eq_classes;		/* list of active EquivalenceClasses */
 
-	List	   *canon_pathkeys; /* list of "canonical" PathKeys */
-
 	List	   *left_join_clauses;		/* list of RestrictInfos for
 										 * mergejoinable outer join clauses
 										 * w/nonnullable var on left */
@@ -527,6 +525,7 @@ typedef struct EquivalenceClass
 	bool		ec_below_outer_join;	/* equivalence applies below an OJ */
 	bool		ec_broken;		/* failed to generate needed clauses? */
 	Index		ec_sortref;		/* originating sortclause label, or 0 */
+	List	   *ec_canon_pathkeys;
 	struct EquivalenceClass *ec_merged; /* set if merged into another EC */
 } EquivalenceClass;