diff --git a/db/dbformat.h b/db/dbformat.h
index a1c30ed..6dc0ba8 100644
--- a/db/dbformat.h
+++ b/db/dbformat.h
@@ -22,7 +22,7 @@ namespace leveldb {
 // Grouping of constants.  We may want to make some of these
 // parameters set via options.
 namespace config {
-static const int kNumLevels = 7;
+static const int kNumLevels = 3;
 
 // Level-0 compaction is started when we hit this many files.
 static const int kL0_CompactionTrigger = 4;
diff --git a/db/version_set.cc b/db/version_set.cc
index a9f16ed..0a9e02d 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -1104,13 +1104,11 @@ int VersionSet::NumLevelFiles(int level) const {
 
 const char* VersionSet::LevelSummary(LevelSummaryStorage* scratch) const {
   // Update code if kNumLevels changes
-  static_assert(config::kNumLevels == 7, "");
+  static_assert(config::kNumLevels == 3, "");
   std::snprintf(
-      scratch->buffer, sizeof(scratch->buffer), "files[ %d %d %d %d %d %d %d ]",
+      scratch->buffer, sizeof(scratch->buffer), "files[ %d %d %d ]",
       int(current_->files_[0].size()), int(current_->files_[1].size()),
-      int(current_->files_[2].size()), int(current_->files_[3].size()),
-      int(current_->files_[4].size()), int(current_->files_[5].size()),
-      int(current_->files_[6].size()));
+      int(current_->files_[2].size()));
   return scratch->buffer;
 }
 
diff --git a/test/ttl_test.cc b/test/ttl_test.cc
index db6e757..ea71c06 100644
--- a/test/ttl_test.cc
+++ b/test/ttl_test.cc
@@ -104,9 +104,7 @@ TEST(TestTTL, CompactionTTL) {
     delete db;
 }
 
-// Time-consuming when kNumLevels is 7, so run this test when kNumLevels is set to 3,
-// the codes on branch light_ver is a version with kNumLevels set to 3.
-// In this case level 2 is the last level with files.
+// Test handling last level with kNumLevels = 3
 TEST(TestTTL, LastLevelCompaction) {
   DB *db;