diff --git a/include/ircd/m/dbs/room_space.h b/include/ircd/m/dbs/room_space.h
index 1ef12658c..4a31ea60b 100644
--- a/include/ircd/m/dbs/room_space.h
+++ b/include/ircd/m/dbs/room_space.h
@@ -13,15 +13,21 @@
 
 namespace ircd::m::dbs
 {
+	using room_space_key_parts = std::tuple<string_view, string_view, int64_t, event::idx>;
+
 	constexpr size_t ROOM_SPACE_KEY_MAX_SIZE
 	{
-		id::MAX_SIZE + event::TYPE_MAX_SIZE + event::STATE_KEY_MAX_SIZE + sizeof(int64_t)
+		id::MAX_SIZE +
+		event::TYPE_MAX_SIZE +
+		event::STATE_KEY_MAX_SIZE +
+		sizeof(int64_t) +
+		sizeof(event::idx)
 	};
 
 	string_view room_space_key(const mutable_buffer &out, const id::room &, const string_view &type, const string_view &state_key, const int64_t &depth, const event::idx & = 0);
 	string_view room_space_key(const mutable_buffer &out, const id::room &, const string_view &type, const string_view &state_key);
 	string_view room_space_key(const mutable_buffer &out, const id::room &, const string_view &type);
-	std::tuple<string_view, string_view, int64_t, event::idx> room_space_key(const string_view &amalgam);
+	room_space_key_parts room_space_key(const string_view &amalgam);
 
 	// room_id | type, state_key, depth, event_idx => --
 	extern db::index room_space;
diff --git a/ircd/m_dbs.cc b/ircd/m_dbs.cc
index 566ae31bd..7c00fcfdd 100644
--- a/ircd/m_dbs.cc
+++ b/ircd/m_dbs.cc
@@ -3225,17 +3225,31 @@ ircd::m::dbs::room_space_key(const mutable_buffer &out_,
 	consume(out, copy(out, type));
 
 	if(!defined(state_key))
+	{
+		assert(depth < 0L && !event_idx);
 		return { data(out_), data(out) };
+	}
 
 	consume(out, copy(out, "\0"_sv));
 	consume(out, copy(out, state_key));
 	consume(out, copy(out, "\0"_sv));
+
+	if(depth < 0)
+	{
+		assert(!event_idx);
+		return { data(out_), data(out) };
+	}
+
 	consume(out, copy(out, byte_view<string_view>(depth)));
+
+	if(!event_idx)
+		return { data(out_), data(out) };
+
 	consume(out, copy(out, byte_view<string_view>(event_idx)));
 	return { data(out_), data(out) };
 }
 
-std::tuple<ircd::string_view, ircd::string_view, int64_t, ircd::m::event::idx>
+ircd::m::dbs::room_space_key_parts
 ircd::m::dbs::room_space_key(const string_view &amalgam)
 {
 	const auto &key