diff --git a/db/db_impl.cc b/db/db_impl.cc
index dd942f36be45afd049169d4a025dbd79e5fb4cf2..1d568d0b1b2bf33d1b5574dbf06567f6d3195cb4 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -1498,6 +1498,18 @@ Status DBImpl::BackgroundCompaction(bool* madeProgress,
     if (!status.ok()) {
       m->done = true;
     }
+    // For universal compaction:
+    //   Because universal compaction always happens at level 0, so one
+    //   compaction will pick up all overlapped files. No files will be
+    //   filtered out due to size limit and left for a successive compaction.
+    //   So we can safely conclude the current compaction.
+    //
+    //   Also note that, if we don't stop here, then the current compaction
+    //   writes a new file back to level 0, which will be used in successive
+    //   compaction. Hence the manual compaction will never finish.
+    if (options_.compaction_style == kCompactionStyleUniversal) {
+      m->done = true;
+    }
     if (!m->done) {
       // We only compacted part of the requested range.  Update *m
       // to the range that is left to be compacted.
@@ -2088,7 +2100,7 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
       versions_->LevelSummary(&tmp),
       (stats.bytes_readn + stats.bytes_readnp1 + stats.bytes_written) /
           (double) stats.micros,
-      compact->compaction->level() + 1,
+      compact->compaction->output_level(),
       stats.files_in_leveln, stats.files_in_levelnp1, stats.files_out_levelnp1,
       stats.bytes_readn / 1048576.0,
       stats.bytes_readnp1 / 1048576.0,
diff --git a/db/db_test.cc b/db/db_test.cc
index b861a4cc42b4bb06b38342c6c432c1d716622a1e..01ff1e046438825dcfb851f5a34c7b4aa4177527 100644
--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -219,6 +219,7 @@ class DBTest {
     kCompactOnFlush,
     kPerfOptions,
     kDeletesFilterFirst,
+    kUniversalCompaction,
     kEnd
   };
   int option_config_;
@@ -232,6 +233,14 @@ class DBTest {
 
   Options last_options_;
 
+  // Skip some options, as they may not be applicable to a specific test.
+  // To add more skip constants, use values 4, 8, 16, etc.
+  enum OptionSkip {
+    kNoSkip = 0,
+    kSkipDeletesFilterFirst = 1,
+    kSkipUniversalCompaction = 2
+  };
+
   DBTest() : option_config_(kDefault),
              merge_operator_(MergeOperators::CreatePutOperator()),
              env_(new SpecialEnv(Env::Default())) {
@@ -251,8 +260,19 @@ class DBTest {
 
   // Switch to a fresh database with the next option configuration to
   // test.  Return false if there are no more configurations to test.
-  bool ChangeOptions() {
+  bool ChangeOptions(int skip_mask = kNoSkip) {
     option_config_++;
+
+    // skip some options
+    if (skip_mask & kSkipDeletesFilterFirst &&
+        option_config_ == kDeletesFilterFirst) {
+      option_config_++;
+    }
+    if (skip_mask & kSkipUniversalCompaction &&
+        option_config_ == kUniversalCompaction) {
+      option_config_++;
+    }
+
     if (option_config_ >= kEnd) {
       return false;
     } else {
@@ -293,6 +313,9 @@ class DBTest {
       case kDeletesFilterFirst:
         options.filter_deletes = true;
         break;
+      case kUniversalCompaction:
+        options.compaction_style = kCompactionStyleUniversal;
+        break;
       default:
         break;
     }
@@ -769,7 +792,7 @@ TEST(DBTest, GetEncountersEmptyLevel) {
     env_->SleepForMicroseconds(1000000);
 
     ASSERT_EQ(NumTableFilesAtLevel(0), 1); // XXX
-  } while (ChangeOptions());
+  } while (ChangeOptions(kSkipUniversalCompaction));
 }
 
 // KeyMayExist can lead to a few false positives, but not false negatives.
@@ -1791,7 +1814,7 @@ TEST(DBTest, ApproximateSizes) {
       ASSERT_EQ(NumTableFilesAtLevel(0), 0);
       ASSERT_GT(NumTableFilesAtLevel(1), 0);
     }
-  } while (ChangeOptions());
+  } while (ChangeOptions(kSkipUniversalCompaction));
 }
 
 TEST(DBTest, ApproximateSizes_MixOfSmallAndLarge) {
@@ -1911,7 +1934,7 @@ TEST(DBTest, HiddenValuesAreRemoved) {
     ASSERT_EQ(AllEntriesFor("foo"), "[ tiny ]");
 
     ASSERT_TRUE(Between(Size("", "pastfoo"), 0, 1000));
-  } while (ChangeOptions());
+  } while (ChangeOptions(kSkipUniversalCompaction));
 }
 
 TEST(DBTest, CompactBetweenSnapshots) {
@@ -2065,7 +2088,7 @@ TEST(DBTest, OverlapInLevel0) {
     dbfull()->TEST_CompactMemTable();
     ASSERT_EQ("3", FilesPerLevel());
     ASSERT_EQ("NOT_FOUND", Get("600"));
-  } while (ChangeOptions());
+  } while (ChangeOptions(kSkipUniversalCompaction));
 }
 
 TEST(DBTest, L0_CompactionBug_Issue44_a) {
@@ -3243,9 +3266,6 @@ static bool CompareIterators(int step,
 TEST(DBTest, Randomized) {
   Random rnd(test::RandomSeed());
   do {
-    if (CurrentOptions().filter_deletes) {
-      ChangeOptions(); // DBTest.Randomized not suited for filter_deletes
-    }
     ModelDB model(CurrentOptions());
     const int N = 10000;
     const Snapshot* model_snap = nullptr;
@@ -3308,7 +3328,9 @@ TEST(DBTest, Randomized) {
     }
     if (model_snap != nullptr) model.ReleaseSnapshot(model_snap);
     if (db_snap != nullptr) db_->ReleaseSnapshot(db_snap);
-  } while (ChangeOptions());
+  // TODO (xjin): remove kSkipUniversalCompaction after bug in
+  //              IsBaseLevelForKey() is fixed.
+  } while (ChangeOptions(kSkipDeletesFilterFirst | kSkipUniversalCompaction));
 }
 
 TEST(DBTest, MultiGetSimple) {
diff --git a/db/version_set.cc b/db/version_set.cc
index 1b5001d5976aac572a2f08896114713e29b69f47..79e868ecb5bb005af620168afd7f45b341c31a2d 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -2403,7 +2403,7 @@ Compaction* VersionSet::PickCompaction() {
     if (level != 0 || compactions_in_progress_[0].empty()) {
       if(!ParentRangeInCompaction(&f->smallest, &f->largest, level,
                                   &parent_index)) {
-        c = new Compaction(level, level, MaxFileSizeForLevel(level+1),
+        c = new Compaction(level, level+1, MaxFileSizeForLevel(level+1),
                 MaxGrandParentOverlapBytes(level), NumberLevels(), true);
         c->inputs_[0].push_back(f);
         c->parent_index_ = parent_index;
diff --git a/util/options.cc b/util/options.cc
index 800c8d32118832c00f89ddfaea4f32195ece55d3..127fe81812728d6bece9f1123a7ddffcabfa8671 100644
--- a/util/options.cc
+++ b/util/options.cc
@@ -185,7 +185,7 @@ Options::Dump(Logger* log) const
         max_background_compactions);
     Log(log,"                      Options.hard_rate_limit: %.2f",
         hard_rate_limit);
-    Log(log,"      Options.rate_limit_delay_max_milliseconds: %d",
+    Log(log,"      Options.rate_limit_delay_max_milliseconds: %u",
         rate_limit_delay_max_milliseconds);
     Log(log,"               Options.disable_auto_compactions: %d",
         disable_auto_compactions);
@@ -205,7 +205,7 @@ Options::Dump(Logger* log) const
         is_fd_close_on_exec);
     Log(log,"              Options.skip_log_error_on_recovery: %d",
         skip_log_error_on_recovery);
-    Log(log,"                   Options.stats_dump_period_sec: %d",
+    Log(log,"                   Options.stats_dump_period_sec: %u",
         stats_dump_period_sec);
     Log(log,"                    Options.block_size_deviation: %d",
         block_size_deviation);
@@ -221,11 +221,11 @@ Options::Dump(Logger* log) const
         filter_deletes);
     Log(log,"                        Options.compaction_style: %d",
         compaction_style);
-    Log(log,"        Options.compaction_options_universal.size_ratio: %d",
+    Log(log,"        Options.compaction_options_universal.size_ratio: %u",
         compaction_options_universal.size_ratio);
-    Log(log,"   Options.compaction_options_universal.min_merge_width: %d",
+    Log(log,"   Options.compaction_options_universal.min_merge_width: %u",
         compaction_options_universal.min_merge_width);
-    Log(log,"   Options.compaction_options_universal.max_merge_width: %d",
+    Log(log,"   Options.compaction_options_universal.max_merge_width: %u",
         compaction_options_universal.max_merge_width);
 }   // Options::Dump