diff --git a/db/db_iter_test.cc b/db/db_iter_test.cc
index 60957367155eed32db5e157a7dcc37eb01ea3fd0..4ce79da1bac7a300b3435d20a2d02661d336f393 100644
--- a/db/db_iter_test.cc
+++ b/db/db_iter_test.cc
@@ -323,23 +323,23 @@ TEST(DBIteratorTest, DBIteratorUseSkipCountSkips) {
   ASSERT_TRUE(db_iter->Valid());
   ASSERT_EQ(db_iter->key().ToString(), "c");
   ASSERT_EQ(db_iter->value().ToString(), "c");
-  ASSERT_EQ(TestGetTickerCount(options, NUMBER_OF_RESEEKS_IN_ITERATION), 1);
+  ASSERT_EQ(TestGetTickerCount(options, NUMBER_OF_RESEEKS_IN_ITERATION), 1u);
 
   db_iter->Prev();
   ASSERT_TRUE(db_iter->Valid());
   ASSERT_EQ(db_iter->key().ToString(), "b");
   ASSERT_EQ(db_iter->value().ToString(), "b");
-  ASSERT_EQ(TestGetTickerCount(options, NUMBER_OF_RESEEKS_IN_ITERATION), 2);
+  ASSERT_EQ(TestGetTickerCount(options, NUMBER_OF_RESEEKS_IN_ITERATION), 2u);
 
   db_iter->Prev();
   ASSERT_TRUE(db_iter->Valid());
   ASSERT_EQ(db_iter->key().ToString(), "a");
   ASSERT_EQ(db_iter->value().ToString(), "a");
-  ASSERT_EQ(TestGetTickerCount(options, NUMBER_OF_RESEEKS_IN_ITERATION), 3);
+  ASSERT_EQ(TestGetTickerCount(options, NUMBER_OF_RESEEKS_IN_ITERATION), 3u);
 
   db_iter->Prev();
   ASSERT_TRUE(!db_iter->Valid());
-  ASSERT_EQ(TestGetTickerCount(options, NUMBER_OF_RESEEKS_IN_ITERATION), 3);
+  ASSERT_EQ(TestGetTickerCount(options, NUMBER_OF_RESEEKS_IN_ITERATION), 3u);
 }
 
 TEST(DBIteratorTest, DBIteratorUseSkip) {
diff --git a/db/version_set_test.cc b/db/version_set_test.cc
index 36520061025f5351d54e746db380e676c07c57d7..402762efa11a7e577d8ffe0bf05beba7fe24dd0b 100644
--- a/db/version_set_test.cc
+++ b/db/version_set_test.cc
@@ -51,14 +51,14 @@ class GenerateFileLevelTest {
 
 TEST(GenerateFileLevelTest, Empty) {
   DoGenerateFileLevel(&file_level_, files_, &arena_);
-  ASSERT_EQ(0, file_level_.num_files);
+  ASSERT_EQ(0u, file_level_.num_files);
   ASSERT_EQ(0, Compare());
 }
 
 TEST(GenerateFileLevelTest, Single) {
   Add("p", "q");
   DoGenerateFileLevel(&file_level_, files_, &arena_);
-  ASSERT_EQ(1, file_level_.num_files);
+  ASSERT_EQ(1u, file_level_.num_files);
   ASSERT_EQ(0, Compare());
 }
 
@@ -69,7 +69,7 @@ TEST(GenerateFileLevelTest, Multiple) {
   Add("300", "350");
   Add("400", "450");
   DoGenerateFileLevel(&file_level_, files_, &arena_);
-  ASSERT_EQ(4, file_level_.num_files);
+  ASSERT_EQ(4u, file_level_.num_files);
   ASSERT_EQ(0, Compare());
 }
 
diff --git a/table/plain_table_reader.h b/table/plain_table_reader.h
index cb1e32f4d2393e2802c65df277ed64596ca3c581..84a2e22c45677bb83b5e7de8addebfec45a54e8d 100644
--- a/table/plain_table_reader.h
+++ b/table/plain_table_reader.h
@@ -26,7 +26,7 @@
 namespace rocksdb {
 
 class Block;
-class BlockContents;
+struct BlockContents;
 class BlockHandle;
 class Footer;
 struct Options;
diff --git a/utilities/document/json_document_test.cc b/utilities/document/json_document_test.cc
index 55d550b3559e7b9387f35054339dadb346c12a3c..886d1981a723b66cba0f92703229b39feb5b61fc 100644
--- a/utilities/document/json_document_test.cc
+++ b/utilities/document/json_document_test.cc
@@ -54,7 +54,7 @@ class JSONDocumentTest {
     ASSERT_TRUE(json.Contains("properties"));
     ASSERT_TRUE(json["properties"].Contains("flags"));
     ASSERT_TRUE(json["properties"]["flags"].IsArray());
-    ASSERT_EQ(3, json["properties"]["flags"].Count());
+    ASSERT_EQ(3u, json["properties"]["flags"].Count());
     ASSERT_TRUE(json["properties"]["flags"][0].IsInt64());
     ASSERT_EQ(10, json["properties"]["flags"][0].GetInt64());
     ASSERT_TRUE(json["properties"]["flags"][1].IsString());
@@ -74,7 +74,7 @@ class JSONDocumentTest {
     ASSERT_EQ(0U, expected.size());
     ASSERT_TRUE(json.Contains("latlong"));
     ASSERT_TRUE(json["latlong"].IsArray());
-    ASSERT_EQ(2, json["latlong"].Count());
+    ASSERT_EQ(2u, json["latlong"].Count());
     ASSERT_TRUE(json["latlong"][0].IsDouble());
     ASSERT_EQ(53.25, json["latlong"][0].GetDouble());
     ASSERT_TRUE(json["latlong"][1].IsDouble());