diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 95752fa31d..751c465bff 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -3832,6 +3832,8 @@ static void AfterTriggerExecute(EState *estate,
 								TupleTableSlot *trig_tuple_slot2);
 static AfterTriggersTableData *GetAfterTriggersTableData(Oid relid,
 														 CmdType cmdType);
+static TupleTableSlot *GetAfterTriggersStoreSlot(AfterTriggersTableData *table,
+												 TupleDesc tupdesc);
 static void AfterTriggerFreeQuery(AfterTriggersQueryData *qs);
 static SetConstraintState SetConstraintStateCreate(int numalloc);
 static SetConstraintState SetConstraintStateCopy(SetConstraintState state);
@@ -4634,6 +4636,31 @@ GetAfterTriggersTableData(Oid relid, CmdType cmdType)
 	return table;
 }
 
+/*
+ * Returns a TupleTableSlot suitable for holding the tuples to be put
+ * into AfterTriggersTableData's transition table tuplestores.
+ */
+static TupleTableSlot *
+GetAfterTriggersStoreSlot(AfterTriggersTableData *table,
+						  TupleDesc tupdesc)
+{
+	/* Create it if not already done. */
+	if (!table->storeslot)
+	{
+		MemoryContext	oldcxt;
+
+		/*
+		 * We only need this slot only until AfterTriggerEndQuery, but making
+		 * it last till end-of-subxact is good enough.  It'll be freed by
+		 * AfterTriggerFreeQuery().
+		 */
+		oldcxt = MemoryContextSwitchTo(CurTransactionContext);
+		table->storeslot = MakeSingleTupleTableSlot(tupdesc, &TTSOpsVirtual);
+		MemoryContextSwitchTo(oldcxt);
+	}
+
+	return table->storeslot;
+}
 
 /*
  * MakeTransitionCaptureState
@@ -4922,6 +4949,8 @@ AfterTriggerFreeQuery(AfterTriggersQueryData *qs)
 		table->new_tuplestore = NULL;
 		if (ts)
 			tuplestore_end(ts);
+		if (table->storeslot)
+			ExecDropSingleTupleTableSlot(table->storeslot);
 	}
 
 	/*
@@ -5771,17 +5800,10 @@ AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 
 			if (map != NULL)
 			{
+				AfterTriggersTableData *table = transition_capture->tcs_private;
 				TupleTableSlot *storeslot;
 
-				storeslot = transition_capture->tcs_private->storeslot;
-				if (!storeslot)
-				{
-					storeslot = ExecAllocTableSlot(&estate->es_tupleTable,
-												   map->outdesc,
-												   &TTSOpsVirtual);
-					transition_capture->tcs_private->storeslot = storeslot;
-				}
-
+				storeslot = GetAfterTriggersStoreSlot(table, map->outdesc);
 				execute_attr_map_slot(map->attrMap, oldslot, storeslot);
 				tuplestore_puttupleslot(old_tuplestore, storeslot);
 			}
@@ -5801,18 +5823,10 @@ AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 										original_insert_tuple);
 			else if (map != NULL)
 			{
+				AfterTriggersTableData *table = transition_capture->tcs_private;
 				TupleTableSlot *storeslot;
 
-				storeslot = transition_capture->tcs_private->storeslot;
-
-				if (!storeslot)
-				{
-					storeslot = ExecAllocTableSlot(&estate->es_tupleTable,
-												   map->outdesc,
-												   &TTSOpsVirtual);
-					transition_capture->tcs_private->storeslot = storeslot;
-				}
-
+				storeslot = GetAfterTriggersStoreSlot(table, map->outdesc);
 				execute_attr_map_slot(map->attrMap, newslot, storeslot);
 				tuplestore_puttupleslot(new_tuplestore, storeslot);
 			}
diff --git a/src/test/regress/expected/triggers.out b/src/test/regress/expected/triggers.out
index 316eefdb6b..38406a2879 100644
--- a/src/test/regress/expected/triggers.out
+++ b/src/test/regress/expected/triggers.out
@@ -3083,3 +3083,62 @@ drop table self_ref;
 drop function dump_insert();
 drop function dump_update();
 drop function dump_delete();
+-- verify transition table conversion slot's lifetime
+-- https://postgr.es/m/39a71864-b120-5a5c-8cc5-c632b6f16761@amazon.com
+create table convslot_test_parent (col1 text primary key);
+create table convslot_test_child (col1 text primary key,
+	foreign key (col1) references convslot_test_parent(col1) on delete cascade on update cascade
+);
+alter table convslot_test_child add column col2 text not null default 'tutu';
+insert into convslot_test_parent(col1) values ('1');
+insert into convslot_test_child(col1) values ('1');
+insert into convslot_test_parent(col1) values ('3');
+insert into convslot_test_child(col1) values ('3');
+create or replace function trigger_function1()
+returns trigger
+language plpgsql
+AS $$
+begin
+raise notice 'trigger = %, old_table = %',
+          TG_NAME,
+          (select string_agg(old_table::text, ', ' order by col1) from old_table);
+return null;
+end; $$;
+create or replace function trigger_function2()
+returns trigger
+language plpgsql
+AS $$
+begin
+raise notice 'trigger = %, new table = %',
+          TG_NAME,
+          (select string_agg(new_table::text, ', ' order by col1) from new_table);
+return null;
+end; $$;
+create trigger but_trigger after update on convslot_test_child
+referencing new table as new_table
+for each statement execute function trigger_function2();
+update convslot_test_parent set col1 = col1 || '1';
+NOTICE:  trigger = but_trigger, new table = (11,tutu), (31,tutu)
+create or replace function trigger_function3()
+returns trigger
+language plpgsql
+AS $$
+begin
+raise notice 'trigger = %, old_table = %, new table = %',
+          TG_NAME,
+          (select string_agg(old_table::text, ', ' order by col1) from old_table),
+          (select string_agg(new_table::text, ', ' order by col1) from new_table);
+return null;
+end; $$;
+create trigger but_trigger2 after update on convslot_test_child
+referencing old table as old_table new table as new_table
+for each statement execute function trigger_function3();
+update convslot_test_parent set col1 = col1 || '1';
+NOTICE:  trigger = but_trigger, new table = (111,tutu), (311,tutu)
+NOTICE:  trigger = but_trigger2, old_table = (11,tutu), (31,tutu), new table = (111,tutu), (311,tutu)
+create trigger bdt_trigger after delete on convslot_test_child
+referencing old table as old_table
+for each statement execute function trigger_function1();
+delete from convslot_test_parent;
+NOTICE:  trigger = bdt_trigger, old_table = (111,tutu), (311,tutu)
+drop table convslot_test_child, convslot_test_parent;
diff --git a/src/test/regress/sql/triggers.sql b/src/test/regress/sql/triggers.sql
index 4caa11d63b..f81ce18109 100644
--- a/src/test/regress/sql/triggers.sql
+++ b/src/test/regress/sql/triggers.sql
@@ -2296,3 +2296,68 @@ drop table self_ref;
 drop function dump_insert();
 drop function dump_update();
 drop function dump_delete();
+
+-- verify transition table conversion slot's lifetime
+-- https://postgr.es/m/39a71864-b120-5a5c-8cc5-c632b6f16761@amazon.com
+create table convslot_test_parent (col1 text primary key);
+create table convslot_test_child (col1 text primary key,
+	foreign key (col1) references convslot_test_parent(col1) on delete cascade on update cascade
+);
+
+alter table convslot_test_child add column col2 text not null default 'tutu';
+insert into convslot_test_parent(col1) values ('1');
+insert into convslot_test_child(col1) values ('1');
+insert into convslot_test_parent(col1) values ('3');
+insert into convslot_test_child(col1) values ('3');
+
+create or replace function trigger_function1()
+returns trigger
+language plpgsql
+AS $$
+begin
+raise notice 'trigger = %, old_table = %',
+          TG_NAME,
+          (select string_agg(old_table::text, ', ' order by col1) from old_table);
+return null;
+end; $$;
+
+create or replace function trigger_function2()
+returns trigger
+language plpgsql
+AS $$
+begin
+raise notice 'trigger = %, new table = %',
+          TG_NAME,
+          (select string_agg(new_table::text, ', ' order by col1) from new_table);
+return null;
+end; $$;
+
+create trigger but_trigger after update on convslot_test_child
+referencing new table as new_table
+for each statement execute function trigger_function2();
+
+update convslot_test_parent set col1 = col1 || '1';
+
+create or replace function trigger_function3()
+returns trigger
+language plpgsql
+AS $$
+begin
+raise notice 'trigger = %, old_table = %, new table = %',
+          TG_NAME,
+          (select string_agg(old_table::text, ', ' order by col1) from old_table),
+          (select string_agg(new_table::text, ', ' order by col1) from new_table);
+return null;
+end; $$;
+
+create trigger but_trigger2 after update on convslot_test_child
+referencing old table as old_table new table as new_table
+for each statement execute function trigger_function3();
+update convslot_test_parent set col1 = col1 || '1';
+
+create trigger bdt_trigger after delete on convslot_test_child
+referencing old table as old_table
+for each statement execute function trigger_function1();
+delete from convslot_test_parent;
+
+drop table convslot_test_child, convslot_test_parent;