fix: less load when lazy loading

src/client_server/sync.rs

@@ -453,13 +453,13 @@ async fn sync_helper(
             let joined_since_last_sync = since_sender_member
                 .map_or(true, |member| member.membership != MembershipState::Join);
 
-            let current_state_ids = db.rooms.state_full_ids(current_shortstatehash)?;
-
-            let since_state_ids = db.rooms.state_full_ids(since_shortstatehash)?;
-
             let mut state_events = Vec::new();
             let mut lazy_loaded = HashSet::new();
 
+            if since_shortstatehash != current_shortstatehash {
+                let current_state_ids = db.rooms.state_full_ids(current_shortstatehash)?;
+                let since_state_ids = db.rooms.state_full_ids(since_shortstatehash)?;
+
                 for (key, id) in current_state_ids {
                     if body.full_state || since_state_ids.get(&key) != Some(&id) {
                         let pdu = match db.rooms.get_pdu(&id)? {
@@ -487,6 +487,7 @@ async fn sync_helper(
                         state_events.push(pdu);
                     }
                 }
+            }
 
             for (_, event) in &timeline_pdus {
                 if lazy_loaded.contains(&event.sender) {