diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index a04d8ec6e6..40d5c4833c 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -483,7 +483,8 @@ ReorderBufferGetTupleBuf(ReorderBuffer *rb, Size tuple_len)
 	{
 		tuple = (ReorderBufferTupleBuf *)
 			MemoryContextAlloc(rb->context,
-							   sizeof(ReorderBufferTupleBuf) + alloc_len);
+							   sizeof(ReorderBufferTupleBuf) +
+							   MAXIMUM_ALIGNOF + alloc_len);
 		tuple->alloc_tuple_size = alloc_len;
 		tuple->tuple.t_data = ReorderBufferTupleBufData(tuple);
 	}