diff --git a/src/compressor.rs b/src/compressor.rs
index 353ec80..73491be 100644
--- a/src/compressor.rs
+++ b/src/compressor.rs
@@ -156,7 +156,7 @@ impl<'a> Compressor<'a> {
     ) -> Compressor<'a> {
         let levels = level_info
             .iter()
-            .map(|l| Level::restore((*l).max_length, (*l).current_chain_length, (*l).head))
+            .map(|l| Level::restore(l.max_length, l.current_chain_length, l.head))
             .collect();
 
         let mut compressor = Compressor {
diff --git a/src/database.rs b/src/database.rs
index 9c5fdb4..72da347 100644
--- a/src/database.rs
+++ b/src/database.rs
@@ -237,15 +237,9 @@ fn load_map_from_db(
         let mut missing_sgs: Vec<_> = state_group_map
             .iter()
             .filter_map(|(_sg, entry)| {
-                if let Some(prev_sg) = entry.prev_state_group {
-                    if state_group_map.contains_key(&prev_sg) {
-                        None
-                    } else {
-                        Some(prev_sg)
-                    }
-                } else {
-                    None
-                }
+                entry
+                    .prev_state_group
+                    .filter(|&prev_sg| !state_group_map.contains_key(&prev_sg))
             })
             .collect();
 
diff --git a/src/lib.rs b/src/lib.rs
index 4d97041..f0ccb09 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -563,7 +563,7 @@ pub fn continue_run(
     let (state_group_map, max_group_found) =
         database::reload_data_from_db(db_url, room_id, start, Some(chunk_size), level_info)?;
 
-    let original_num_rows = state_group_map.iter().map(|(_, v)| v.state_map.len()).sum();
+    let original_num_rows = state_group_map.values().map(|v| v.state_map.len()).sum();
 
     // Now we actually call the compression algorithm.
     let compressor = Compressor::compress_from_save(&state_group_map, level_info);