1 files changed, 64 insertions, 6 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index f4cc90183a4..c5452e3cb6a 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -103,7 +103,8 @@ static void ExplainIndexScanDetails(Oid indexid, ScanDirection indexorderdir,
 static void ExplainScanTarget(Scan *plan, ExplainState *es);
 static void ExplainModifyTarget(ModifyTable *plan, ExplainState *es);
 static void ExplainTargetRel(Plan *plan, Index rti, ExplainState *es);
-static void show_modifytable_info(ModifyTableState *mtstate, ExplainState *es);
+static void show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
+					  ExplainState *es);
 static void ExplainMemberNodes(List *plans, PlanState **planstates,
 				   List *ancestors, ExplainState *es);
 static void ExplainSubPlans(List *plans, List *ancestors,
@@ -744,6 +745,9 @@ ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used)
 		case T_ModifyTable:
 			*rels_used = bms_add_member(*rels_used,
 									((ModifyTable *) plan)->nominalRelation);
+			if (((ModifyTable *) plan)->exclRelRTI)
+				*rels_used = bms_add_member(*rels_used,
+											((ModifyTable *) plan)->exclRelRTI);
 			break;
 		default:
 			break;
@@ -1466,7 +1470,8 @@ ExplainNode(PlanState *planstate, List *ancestors,
 										   planstate, es);
 			break;
 		case T_ModifyTable:
-			show_modifytable_info((ModifyTableState *) planstate, es);
+			show_modifytable_info((ModifyTableState *) planstate, ancestors,
+								  es);
 			break;
 		case T_Hash:
 			show_hash_info((HashState *) planstate, es);
@@ -2317,18 +2322,22 @@ ExplainTargetRel(Plan *plan, Index rti, ExplainState *es)
 /*
  * Show extra information for a ModifyTable node
  *
- * We have two objectives here.  First, if there's more than one target table
- * or it's different from the nominal target, identify the actual target(s).
- * Second, give FDWs a chance to display extra info about foreign targets.
+ * We have three objectives here.  First, if there's more than one target
+ * table or it's different from the nominal target, identify the actual
+ * target(s).  Second, give FDWs a chance to display extra info about foreign
+ * targets.  Third, show information about ON CONFLICT.
  */
 static void
-show_modifytable_info(ModifyTableState *mtstate, ExplainState *es)
+show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
+					  ExplainState *es)
 {
 	ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
 	const char *operation;
 	const char *foperation;
 	bool		labeltargets;
 	int			j;
+	List	   *idxNames = NIL;
+	ListCell   *lst;
 
 	switch (node->operation)
 	{
@@ -2414,6 +2423,55 @@ show_modifytable_info(ModifyTableState *mtstate, ExplainState *es)
 		}
 	}
 
+	/* Gather names of ON CONFLICT arbiter indexes */
+	foreach(lst, node->arbiterIndexes)
+	{
+		char	   *indexname = get_rel_name(lfirst_oid(lst));
+
+		idxNames = lappend(idxNames, indexname);
+	}
+
+	if (node->onConflictAction != ONCONFLICT_NONE)
+	{
+		ExplainProperty("Conflict Resolution",
+						node->onConflictAction == ONCONFLICT_NOTHING ?
+							"NOTHING" : "UPDATE",
+						false, es);
+
+		/*
+		 * Don't display arbiter indexes at all when DO NOTHING variant
+		 * implicitly ignores all conflicts
+		 */
+		if (idxNames)
+			ExplainPropertyList("Conflict Arbiter Indexes", idxNames, es);
+
+		/* ON CONFLICT DO UPDATE WHERE qual is specially displayed */
+		if (node->onConflictWhere)
+		{
+			show_upper_qual((List *) node->onConflictWhere, "Conflict Filter",
+							&mtstate->ps, ancestors, es);
+			show_instrumentation_count("Rows Removed by Conflict Filter", 1, &mtstate->ps, es);
+		}
+
+		/* EXPLAIN ANALYZE display of actual outcome for each tuple proposed */
+		if (es->analyze && mtstate->ps.instrument)
+		{
+			double total;
+			double insert_path;
+			double other_path;
+
+			InstrEndLoop(mtstate->mt_plans[0]->instrument);
+
+			/* count the number of source rows */
+			total = mtstate->mt_plans[0]->instrument->ntuples;
+			other_path = mtstate->ps.instrument->nfiltered2;
+			insert_path = total - other_path;
+
+			ExplainPropertyFloat("Tuples Inserted", insert_path, 0, es);
+			ExplainPropertyFloat("Conflicting Tuples", other_path, 0, es);
+		}
+	}
+
 	if (labeltargets)
 		ExplainCloseGroup("Target Tables", "Target Tables", false, es);
 }