diff --git a/mini-lsm-mvcc/src/compact.rs b/mini-lsm-mvcc/src/compact.rs
index cc52c63f..56362961 100644
--- a/mini-lsm-mvcc/src/compact.rs
+++ b/mini-lsm-mvcc/src/compact.rs
@@ -249,7 +249,7 @@ impl LsmStorageInner {
                         upper_ssts.push(snapshot.sstables.get(id).unwrap().clone());
                     }
                     let upper_iter = SstConcatIterator::create_and_seek_to_first(upper_ssts)?;
-                    let mut lower_ssts = Vec::with_capacity(upper_level_sst_ids.len());
+                    let mut lower_ssts = Vec::with_capacity(lower_level_sst_ids.len());
                     for id in lower_level_sst_ids.iter() {
                         lower_ssts.push(snapshot.sstables.get(id).unwrap().clone());
                     }
@@ -267,7 +267,7 @@ impl LsmStorageInner {
                         )?));
                     }
                     let upper_iter = MergeIterator::create(upper_iters);
-                    let mut lower_ssts = Vec::with_capacity(upper_level_sst_ids.len());
+                    let mut lower_ssts = Vec::with_capacity(lower_level_sst_ids.len());
                     for id in lower_level_sst_ids.iter() {
                         lower_ssts.push(snapshot.sstables.get(id).unwrap().clone());
                     }
diff --git a/mini-lsm-mvcc/src/lsm_storage.rs b/mini-lsm-mvcc/src/lsm_storage.rs
index 25786dfd..ad7022cc 100644
--- a/mini-lsm-mvcc/src/lsm_storage.rs
+++ b/mini-lsm-mvcc/src/lsm_storage.rs
@@ -513,7 +513,7 @@ impl LsmStorageInner {
         let l0_iter = MergeIterator::create(l0_iters);
         let mut level_iters = Vec::with_capacity(snapshot.levels.len());
         for (_, level_sst_ids) in &snapshot.levels {
-            let mut level_ssts = Vec::with_capacity(snapshot.levels[0].1.len());
+            let mut level_ssts = Vec::with_capacity(level_sst_ids.len());
             for table in level_sst_ids {
                 let table = snapshot.sstables[table].clone();
                 if keep_table(key, &table) {
diff --git a/mini-lsm/src/compact.rs b/mini-lsm/src/compact.rs
index f095a197..fd4ec75f 100644
--- a/mini-lsm/src/compact.rs
+++ b/mini-lsm/src/compact.rs
@@ -203,7 +203,7 @@ impl LsmStorageInner {
                         upper_ssts.push(snapshot.sstables.get(id).unwrap().clone());
                     }
                     let upper_iter = SstConcatIterator::create_and_seek_to_first(upper_ssts)?;
-                    let mut lower_ssts = Vec::with_capacity(upper_level_sst_ids.len());
+                    let mut lower_ssts = Vec::with_capacity(lower_level_sst_ids.len());
                     for id in lower_level_sst_ids.iter() {
                         lower_ssts.push(snapshot.sstables.get(id).unwrap().clone());
                     }
@@ -221,7 +221,7 @@ impl LsmStorageInner {
                         )?));
                     }
                     let upper_iter = MergeIterator::create(upper_iters);
-                    let mut lower_ssts = Vec::with_capacity(upper_level_sst_ids.len());
+                    let mut lower_ssts = Vec::with_capacity(lower_level_sst_ids.len());
                     for id in lower_level_sst_ids.iter() {
                         lower_ssts.push(snapshot.sstables.get(id).unwrap().clone());
                     }
diff --git a/mini-lsm/src/lsm_storage.rs b/mini-lsm/src/lsm_storage.rs
index 0ee8497a..7b59122a 100644
--- a/mini-lsm/src/lsm_storage.rs
+++ b/mini-lsm/src/lsm_storage.rs
@@ -503,7 +503,7 @@ impl LsmStorageInner {
         let l0_iter = MergeIterator::create(l0_iters);
         let mut level_iters = Vec::with_capacity(snapshot.levels.len());
         for (_, level_sst_ids) in &snapshot.levels {
-            let mut level_ssts = Vec::with_capacity(snapshot.levels[0].1.len());
+            let mut level_ssts = Vec::with_capacity(level_sst_ids.len());
             for table in level_sst_ids {
                 let table = snapshot.sstables[table].clone();
                 if keep_table(key, &table) {