From 68bda043c909200fc672860827b56f37135fac8a Mon Sep 17 00:00:00 2001
From: Onder Kalaci <onderkalaci@gmail.com>
Date: Mon, 15 Feb 2021 18:50:59 +0100
Subject: [PATCH] WIP

---
 .../distributed/planner/recursive_planning.c  | 87 +------------------
 .../relation_restriction_equivalence.c        |  5 ++
 2 files changed, 7 insertions(+), 85 deletions(-)

diff --git a/src/backend/distributed/planner/recursive_planning.c b/src/backend/distributed/planner/recursive_planning.c
index 63aeb3a37..bb8591a8c 100644
--- a/src/backend/distributed/planner/recursive_planning.c
+++ b/src/backend/distributed/planner/recursive_planning.c
@@ -110,7 +110,6 @@ struct RecursivePlanningContextInternal
 	int level;
 	uint64 planId;
 	bool allDistributionKeysInQueryAreEqual; /* used for some optimizations */
-	bool setOperationJoinWithAnyRTE;
 	List *subPlanList;
 	PlannerRestrictionContext *plannerRestrictionContext;
 };
@@ -142,7 +141,6 @@ typedef struct VarLevelsUpWalkerContext
 static DeferredErrorMessage * RecursivelyPlanSubqueriesAndCTEs(Query *query,
 															   RecursivePlanningContext *
 															   context);
-static bool ContainsSetOperationJoinRTE(JoinRestrictionContext *joinRestrictionContext);
 static bool ShouldRecursivelyPlanNonColocatedSubqueries(Query *subquery,
 														RecursivePlanningContext *
 														context);
@@ -222,10 +220,6 @@ GenerateSubplansForSubqueriesAndCTEs(uint64 planId, Query *originalQuery,
 	context.subPlanList = NIL;
 	context.plannerRestrictionContext = plannerRestrictionContext;
 
-	context.setOperationJoinWithAnyRTE =
-		ContainsSetOperationJoinRTE(plannerRestrictionContext->joinRestrictionContext);
-
-
 	/*
 	 * Calculating the distribution key equality upfront is a trade-off for us.
 	 *
@@ -238,12 +232,8 @@ GenerateSubplansForSubqueriesAndCTEs(uint64 planId, Query *originalQuery,
 	 * calculating this wouldn't help us at all, we should individually check
 	 * each each subquery and subquery joins among subqueries.
 	 */
-	if (!context.setOperationJoinWithAnyRTE)
-	{
-		context.allDistributionKeysInQueryAreEqual =
-			AllDistributionKeysInQueryAreEqual(originalQuery, plannerRestrictionContext);
-	}
-
+	context.allDistributionKeysInQueryAreEqual =
+		AllDistributionKeysInQueryAreEqual(originalQuery, plannerRestrictionContext);
 
 	DeferredErrorMessage *error = RecursivelyPlanSubqueriesAndCTEs(originalQuery,
 																   &context);
@@ -269,74 +259,6 @@ GenerateSubplansForSubqueriesAndCTEs(uint64 planId, Query *originalQuery,
 }
 
 
-static bool
-ContainsSetOperationJoinRTE(JoinRestrictionContext *joinRestrictionContext)
-{
-	List *attributeEquivalenceList = NIL;
-	ListCell *joinRestrictionCell = NULL;
-
-	if (joinRestrictionContext == NULL)
-	{
-		return false;
-	}
-
-	foreach(joinRestrictionCell, joinRestrictionContext->joinRestrictionList)
-	{
-		JoinRestriction *joinRestriction =
-			(JoinRestriction *) lfirst(joinRestrictionCell);
-		ListCell *restrictionInfoList = NULL;
-
-		foreach(restrictionInfoList, joinRestriction->joinRestrictInfoList)
-		{
-			RestrictInfo *rinfo = (RestrictInfo *) lfirst(restrictionInfoList);
-			Expr *restrictionClause = rinfo->clause;
-
-			if (!IsA(restrictionClause, OpExpr))
-			{
-				continue;
-			}
-
-			OpExpr *restrictionOpExpr = (OpExpr *) restrictionClause;
-			if (list_length(restrictionOpExpr->args) != 2)
-			{
-				continue;
-			}
-			if (!OperatorImplementsEquality(restrictionOpExpr->opno))
-			{
-				continue;
-			}
-
-			Node *leftNode = linitial(restrictionOpExpr->args);
-			Node *rightNode = lsecond(restrictionOpExpr->args);
-
-			/* we also don't want implicit coercions */
-			Expr *strippedLeftExpr = (Expr *) strip_implicit_coercions((Node *) leftNode);
-			Expr *strippedRightExpr =
-				(Expr *) strip_implicit_coercions((Node *) rightNode);
-
-			if (!(IsA(strippedLeftExpr, Var) && IsA(strippedRightExpr, Var)))
-			{
-				continue;
-			}
-
-			PlannerInfo *root = joinRestriction->plannerInfo;
-			Var *leftVar = (Var *) strippedLeftExpr;
-			RangeTblEntry *leftRangeTblEntry = root->simple_rte_array[leftVar->varno];
-
-			Var *rightVar = (Var *) strippedRightExpr;
-			RangeTblEntry *rightRangeTblEntry = root->simple_rte_array[rightVar->varno];
-
-			if (leftRangeTblEntry->inh || rightRangeTblEntry->inh)
-			{
-				return true;
-			}
-		}
-	}
-
-	return false;
-}
-
-
 /*
  * RecursivelyPlanSubqueriesAndCTEs finds subqueries and CTEs that cannot be pushed down to
  * workers directly and instead plans them by recursively calling the planner and
@@ -1088,11 +1010,6 @@ ShouldRecursivelyPlanSetOperation(Query *query, RecursivePlanningContext *contex
 		return true;
 	}
 
-	if (context->setOperationJoinWithAnyRTE)
-	{
-		return true;
-	}
-
 	if (DeferErrorIfUnsupportedUnionQuery(query) != NULL)
 	{
 		/*
diff --git a/src/backend/distributed/planner/relation_restriction_equivalence.c b/src/backend/distributed/planner/relation_restriction_equivalence.c
index 0633f709f..2c32135c1 100644
--- a/src/backend/distributed/planner/relation_restriction_equivalence.c
+++ b/src/backend/distributed/planner/relation_restriction_equivalence.c
@@ -1362,6 +1362,11 @@ AddUnionAllSetOperationsToAttributeEquivalenceClass(AttributeEquivalenceClass **
 	List *appendRelList = root->append_rel_list;
 	ListCell *appendRelCell = NULL;
 
+	if (root->simple_rel_array_size != 1)
+	{
+		return;
+	}
+
 	/* iterate on the queries that are part of UNION ALL subqueries */
 	foreach(appendRelCell, appendRelList)
 	{