0002-remove-alternativesubplan-executor-2.patch

diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
index 236413f62a..868f8b0858 100644
--- a/src/backend/executor/execExpr.c
+++ b/src/backend/executor/execExpr.c
@@ -1104,23 +1104,6 @@ ExecInitExprRec(Expr *node, ExprState *state,
 				break;
 			}
 
-		case T_AlternativeSubPlan:
-			{
-				AlternativeSubPlan *asplan = (AlternativeSubPlan *) node;
-				AlternativeSubPlanState *asstate;
-
-				if (!state->parent)
-					elog(ERROR, "AlternativeSubPlan found with no parent plan");
-
-				asstate = ExecInitAlternativeSubPlan(asplan, state->parent);
-
-				scratch.opcode = EEOP_ALTERNATIVE_SUBPLAN;
-				scratch.d.alternative_subplan.asstate = asstate;
-
-				ExprEvalPushStep(state, &scratch);
-				break;
-			}
-
 		case T_FieldSelect:
 			{
 				FieldSelect *fselect = (FieldSelect *) node;
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index b812bbacee..26c2b49632 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -431,7 +431,6 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
 		&&CASE_EEOP_GROUPING_FUNC,
 		&&CASE_EEOP_WINDOW_FUNC,
 		&&CASE_EEOP_SUBPLAN,
-		&&CASE_EEOP_ALTERNATIVE_SUBPLAN,
 		&&CASE_EEOP_AGG_STRICT_DESERIALIZE,
 		&&CASE_EEOP_AGG_DESERIALIZE,
 		&&CASE_EEOP_AGG_STRICT_INPUT_CHECK_ARGS,
@@ -1536,14 +1535,6 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
 			EEO_NEXT();
 		}
 
-		EEO_CASE(EEOP_ALTERNATIVE_SUBPLAN)
-		{
-			/* too complex for an inline implementation */
-			ExecEvalAlternativeSubPlan(state, op, econtext);
-
-			EEO_NEXT();
-		}
-
 		/* evaluate a strict aggregate deserialization function */
 		EEO_CASE(EEOP_AGG_STRICT_DESERIALIZE)
 		{
@@ -3868,20 +3859,6 @@ ExecEvalSubPlan(ExprState *state, ExprEvalStep *op, ExprContext *econtext)
 	*op->resvalue = ExecSubPlan(sstate, econtext, op->resnull);
 }
 
-/*
- * Hand off evaluation of an alternative subplan to nodeSubplan.c
- */
-void
-ExecEvalAlternativeSubPlan(ExprState *state, ExprEvalStep *op, ExprContext *econtext)
-{
-	AlternativeSubPlanState *asstate = op->d.alternative_subplan.asstate;
-
-	/* could potentially be nested, so make sure there's enough stack */
-	check_stack_depth();
-
-	*op->resvalue = ExecAlternativeSubPlan(asstate, econtext, op->resnull);
-}
-
 /*
  * Evaluate a wholerow Var expression.
  *
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 9a7962518e..9a706df5f0 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -1303,83 +1303,3 @@ ExecReScanSetParamPlan(SubPlanState *node, PlanState *parent)
 		parent->chgParam = bms_add_member(parent->chgParam, paramid);
 	}
 }
-
-
-/*
- * ExecInitAlternativeSubPlan
- *
- * Initialize for execution of one of a set of alternative subplans.
- */
-AlternativeSubPlanState *
-ExecInitAlternativeSubPlan(AlternativeSubPlan *asplan, PlanState *parent)
-{
-	AlternativeSubPlanState *asstate = makeNode(AlternativeSubPlanState);
-	double		num_calls;
-	SubPlan    *subplan1;
-	SubPlan    *subplan2;
-	Cost		cost1;
-	Cost		cost2;
-	ListCell   *lc;
-
-	asstate->subplan = asplan;
-
-	/*
-	 * Initialize subplans.  (Can we get away with only initializing the one
-	 * we're going to use?)
-	 */
-	foreach(lc, asplan->subplans)
-	{
-		SubPlan    *sp = lfirst_node(SubPlan, lc);
-		SubPlanState *sps = ExecInitSubPlan(sp, parent);
-
-		asstate->subplans = lappend(asstate->subplans, sps);
-		parent->subPlan = lappend(parent->subPlan, sps);
-	}
-
-	/*
-	 * Select the one to be used.  For this, we need an estimate of the number
-	 * of executions of the subplan.  We use the number of output rows
-	 * expected from the parent plan node.  This is a good estimate if we are
-	 * in the parent's targetlist, and an underestimate (but probably not by
-	 * more than a factor of 2) if we are in the qual.
-	 */
-	num_calls = parent->plan->plan_rows;
-
-	/*
-	 * The planner saved enough info so that we don't have to work very hard
-	 * to estimate the total cost, given the number-of-calls estimate.
-	 */
-	Assert(list_length(asplan->subplans) == 2);
-	subplan1 = (SubPlan *) linitial(asplan->subplans);
-	subplan2 = (SubPlan *) lsecond(asplan->subplans);
-
-	cost1 = subplan1->startup_cost + num_calls * subplan1->per_call_cost;
-	cost2 = subplan2->startup_cost + num_calls * subplan2->per_call_cost;
-
-	if (cost1 < cost2)
-		asstate->active = 0;
-	else
-		asstate->active = 1;
-
-	return asstate;
-}
-
-/*
- * ExecAlternativeSubPlan
- *
- * Execute one of a set of alternative subplans.
- *
- * Note: in future we might consider changing to different subplans on the
- * fly, in case the original rowcount estimate turns out to be way off.
- */
-Datum
-ExecAlternativeSubPlan(AlternativeSubPlanState *node,
-					   ExprContext *econtext,
-					   bool *isNull)
-{
-	/* Just pass control to the active subplan */
-	SubPlanState *activesp = list_nth_node(SubPlanState,
-										   node->subplans, node->active);
-
-	return ExecSubPlan(activesp, econtext, isNull);
-}
diff --git a/src/backend/jit/llvm/llvmjit_expr.c b/src/backend/jit/llvm/llvmjit_expr.c
index cca5c117a0..eb1dea658c 100644
--- a/src/backend/jit/llvm/llvmjit_expr.c
+++ b/src/backend/jit/llvm/llvmjit_expr.c
@@ -1918,12 +1918,6 @@ llvm_compile_expr(ExprState *state)
 				LLVMBuildBr(b, opblocks[opno + 1]);
 				break;
 
-			case EEOP_ALTERNATIVE_SUBPLAN:
-				build_EvalXFunc(b, mod, "ExecEvalAlternativeSubPlan",
-								v_state, op, v_econtext);
-				LLVMBuildBr(b, opblocks[opno + 1]);
-				break;
-
 			case EEOP_AGG_STRICT_DESERIALIZE:
 			case EEOP_AGG_DESERIALIZE:
 				{
diff --git a/src/backend/jit/llvm/llvmjit_types.c b/src/backend/jit/llvm/llvmjit_types.c
index 0a93d5f665..1ed3cafa2f 100644
--- a/src/backend/jit/llvm/llvmjit_types.c
+++ b/src/backend/jit/llvm/llvmjit_types.c
@@ -102,7 +102,6 @@ void	   *referenced_functions[] =
 	ExecAggTransReparent,
 	ExecEvalAggOrderedTransDatum,
 	ExecEvalAggOrderedTransTuple,
-	ExecEvalAlternativeSubPlan,
 	ExecEvalArrayCoerce,
 	ExecEvalArrayExpr,
 	ExecEvalConstraintCheck,
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 60dd80c23c..0e3084325e 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -8192,7 +8192,12 @@ get_rule_expr(Node *node, deparse_context *context,
 				AlternativeSubPlan *asplan = (AlternativeSubPlan *) node;
 				ListCell   *lc;
 
-				/* As above, this can only happen during EXPLAIN */
+				/*
+				 * This case cannot be reached in normal usage, since no
+				 * AlternativeSubPlan can appear either in parsetrees or
+				 * finished plan trees.  We keep it just in case somebody
+				 * wants to use this code to print planner data structures.
+				 */
 				appendStringInfoString(buf, "(alternatives: ");
 				foreach(lc, asplan->subplans)
 				{
diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h
index dbe8649a57..b792de1bc9 100644
--- a/src/include/executor/execExpr.h
+++ b/src/include/executor/execExpr.h
@@ -218,7 +218,6 @@ typedef enum ExprEvalOp
 	EEOP_GROUPING_FUNC,
 	EEOP_WINDOW_FUNC,
 	EEOP_SUBPLAN,
-	EEOP_ALTERNATIVE_SUBPLAN,
 
 	/* aggregation related nodes */
 	EEOP_AGG_STRICT_DESERIALIZE,
@@ -589,13 +588,6 @@ typedef struct ExprEvalStep
 			SubPlanState *sstate;
 		}			subplan;
 
-		/* for EEOP_ALTERNATIVE_SUBPLAN */
-		struct
-		{
-			/* out-of-line state, created by nodeSubplan.c */
-			AlternativeSubPlanState *asstate;
-		}			alternative_subplan;
-
 		/* for EEOP_AGG_*DESERIALIZE */
 		struct
 		{
@@ -734,8 +726,6 @@ extern void ExecEvalXmlExpr(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalGroupingFunc(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalSubPlan(ExprState *state, ExprEvalStep *op,
 							ExprContext *econtext);
-extern void ExecEvalAlternativeSubPlan(ExprState *state, ExprEvalStep *op,
-									   ExprContext *econtext);
 extern void ExecEvalWholeRowVar(ExprState *state, ExprEvalStep *op,
 								ExprContext *econtext);
 extern void ExecEvalSysVar(ExprState *state, ExprEvalStep *op,
diff --git a/src/include/executor/nodeSubplan.h b/src/include/executor/nodeSubplan.h
index 83e90b3d07..b629af1f5f 100644
--- a/src/include/executor/nodeSubplan.h
+++ b/src/include/executor/nodeSubplan.h
@@ -18,12 +18,8 @@
 
 extern SubPlanState *ExecInitSubPlan(SubPlan *subplan, PlanState *parent);
 
-extern AlternativeSubPlanState *ExecInitAlternativeSubPlan(AlternativeSubPlan *asplan, PlanState *parent);
-
 extern Datum ExecSubPlan(SubPlanState *node, ExprContext *econtext, bool *isNull);
 
-extern Datum ExecAlternativeSubPlan(AlternativeSubPlanState *node, ExprContext *econtext, bool *isNull);
-
 extern void ExecReScanSetParamPlan(SubPlanState *node, PlanState *parent);
 
 extern void ExecSetParamPlan(SubPlanState *node, ExprContext *econtext);
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 0b42dd6f94..7e02afa6ba 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -880,18 +880,6 @@ typedef struct SubPlanState
 	ExprState  *cur_eq_comp;	/* equality comparator for LHS vs. table */
 } SubPlanState;
 
-/* ----------------
- *		AlternativeSubPlanState node
- * ----------------
- */
-typedef struct AlternativeSubPlanState
-{
-	NodeTag		type;
-	AlternativeSubPlan *subplan;	/* expression plan node */
-	List	   *subplans;		/* SubPlanStates of alternative subplans */
-	int			active;			/* list index of the one we're using */
-} AlternativeSubPlanState;
-
 /*
  * DomainConstraintState - one item to check during CoerceToDomain
  *
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 381d84b4e4..7ddd8c011b 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -213,7 +213,6 @@ typedef enum NodeTag
 	T_WindowFuncExprState,
 	T_SetExprState,
 	T_SubPlanState,
-	T_AlternativeSubPlanState,
 	T_DomainConstraintState,
 
 	/*