first_partial_plan_fix.patch

diff --git a/src/backend/executor/nodeAppend.c b/src/backend/executor/nodeAppend.c
index d062cfddac..188399cc12 100644
--- a/src/backend/executor/nodeAppend.c
+++ b/src/backend/executor/nodeAppend.c
@@ -204,6 +204,13 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 	appendplanstates = (PlanState **) palloc(nplans *
 											 sizeof(PlanState *));
 
+	/*
+	 * We must determine the first valid partial plan.  Default this to point
+	 * beyond the final valid plan.  We'll determine the actual first valid
+	 * partial subplan in the loop below.
+	 */
+	appendstate->as_first_partial_plan = nplans;
+
 	/*
 	 * call ExecInitNode on each of the valid plans to be executed and save
 	 * the results into the appendplanstates array.
@@ -215,6 +222,13 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 		{
 			Plan	   *initNode = (Plan *) lfirst(lc);
 
+			/*
+			 * Record the lowest appendplanstates index which is a partial
+			 * plan.
+			 */
+			if (i >= node->first_partial_plan && j < appendstate->as_first_partial_plan)
+				appendstate->as_first_partial_plan = j;
+
 			appendplanstates[j++] = ExecInitNode(initNode, estate, eflags);
 		}
 		i++;
@@ -556,7 +570,7 @@ choose_next_subplan_for_leader(AppendState *node)
 	}
 
 	/* If non-partial, immediately mark as finished. */
-	if (node->as_whichplan < append->first_partial_plan)
+	if (node->as_whichplan < node->as_first_partial_plan)
 		node->as_pstate->pa_finished[node->as_whichplan] = true;
 
 	LWLockRelease(&pstate->pa_lock);
@@ -629,14 +643,14 @@ choose_next_subplan_for_worker(AppendState *node)
 			/* Advance to the next valid plan. */
 			pstate->pa_next_plan = nextplan;
 		}
-		else if (node->as_whichplan > append->first_partial_plan)
+		else if (node->as_whichplan > node->as_first_partial_plan)
 		{
 			/*
 			 * Try looping back to the first valid partial plan, if there is
 			 * one.  If there isn't, arrange to bail out below.
 			 */
 			nextplan = bms_next_member(node->as_valid_subplans,
-									   append->first_partial_plan - 1);
+									   node->as_first_partial_plan - 1);
 			pstate->pa_next_plan =
 				nextplan < 0 ? node->as_whichplan : nextplan;
 		}
@@ -670,7 +684,7 @@ choose_next_subplan_for_worker(AppendState *node)
 	if (pstate->pa_next_plan < 0)
 	{
 		int			nextplan = bms_next_member(node->as_valid_subplans,
-											   append->first_partial_plan - 1);
+											   node->as_first_partial_plan - 1);
 
 		if (nextplan >= 0)
 			pstate->pa_next_plan = nextplan;
@@ -686,7 +700,7 @@ choose_next_subplan_for_worker(AppendState *node)
 	}
 
 	/* If non-partial, immediately mark as finished. */
-	if (node->as_whichplan < append->first_partial_plan)
+	if (node->as_whichplan < node->as_first_partial_plan)
 		node->as_pstate->pa_finished[node->as_whichplan] = true;
 
 	LWLockRelease(&pstate->pa_lock);
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index deab875466..cff64337e2 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1150,6 +1150,8 @@ struct AppendState
 	PlanState **appendplans;	/* array of PlanStates for my inputs */
 	int			as_nplans;
 	int			as_whichplan;
+	int			as_first_partial_plan; /* Index of 'appendplans' containing
+										* the first partial plan */
 	ParallelAppendState *as_pstate; /* parallel coordination info */
 	Size		pstate_len;		/* size of parallel coordination info */
 	struct PartitionPruneState *as_prune_state;