update history and version

Summary:
Close https://github.com/facebook/rocksdb/issues/3592
Closes https://github.com/facebook/rocksdb/pull/3614

Differential Revision: D7291706

Pulled By: ajkr

fbshipit-source-id: 9dd8f40bd7716588e1e3fd6be0c2bc2766861f8c

HISTORY.md

@@ -1,5 +1,22 @@
 # Rocksdb Change Log
-## Unreleased
+## 5.13.3 (6/6/2018)
+### Bug Fixes
+* Fix assertion when reading bloom filter of SST files containing range deletions but no data
+
+## 5.13.2 (5/25/2018)
+### Public API Change
+* Introduced `CompressionOptions::kDefaultCompressionLevel`, which is a generic way to tell RocksDB to use the compression library's default level. It is now the default value for `CompressionOptions::level`. Previously the level defaulted to -1, which gave poor compression ratios in ZSTD.
+
+### Bug Fixes
+* Fix segfault caused by object premature destruction (PR #3898)
+* Fix an issue with unnecessary capture in lambda expressions (PR #3904)
+
+## 5.13.1 (4/30/2018)
+### New Features
+* Add `Env::LowerThreadPoolCPUPriority(Priority)` method, which lowers the CPU priority of background (esp. compaction) threads to minimize interference with foreground tasks.
+* Eliminate use of temporary directories in BackupEngine to improve reliability on distributed file systems.
+
+## 5.13.0 (3/20/2018)
 ### Public API Change
 * RocksDBOptionsParser::Parse()'s `ignore_unknown_options` argument will only be effective if the option file shows it is generated using a higher version of RocksDB than the current version.
 * Remove CompactionEventListener.
@@ -13,6 +30,11 @@
 ### Bug Fixes
 * Fix a leak in prepared_section_completed_ where the zeroed entries would not removed from the map.
 * Fix WAL corruption caused by race condition between user write thread and backup/checkpoint thread.
+* Fsync after writing global seq number to the ingestion file in ExternalSstFileIngestionJob.
+* Fix memory leak when pin_l0_filter_and_index_blocks_in_cache is used with partitioned filters
+
+### Java API Changes
+* Add `BlockBasedTableConfig.setBlockCache` to allow sharing a block cache across DB instances.
 
 ## 5.12.0 (2/14/2018)
 ### Public API Change

db/column_family_test.cc

@@ -383,6 +383,9 @@ class ColumnFamilyTest : public testing::Test {
   void AssertFilesPerLevel(const std::string& value, int cf) {
 #ifndef ROCKSDB_LITE
     ASSERT_EQ(value, FilesPerLevel(cf));
+#else
+    (void) value;
+    (void) cf;
 #endif
   }
 
@@ -397,6 +400,8 @@ class ColumnFamilyTest : public testing::Test {
   void AssertCountLiveFiles(int expected_value) {
 #ifndef ROCKSDB_LITE
     ASSERT_EQ(expected_value, CountLiveFiles());
+#else
+    (void) expected_value;
 #endif
   }
 
@@ -445,6 +450,8 @@ class ColumnFamilyTest : public testing::Test {
   void AssertCountLiveLogFiles(int value) {
 #ifndef ROCKSDB_LITE  // GetSortedWalFiles is not supported
     ASSERT_EQ(value, CountLiveLogFiles());
+#else
+    (void) value;
 #endif  // !ROCKSDB_LITE
   }
 
@@ -2791,6 +2798,39 @@ TEST_F(ColumnFamilyTest, CompactionSpeedupTwoColumnFamilies) {
   ASSERT_EQ(1, dbfull()->TEST_BGCompactionsAllowed());
 }
 
+TEST_F(ColumnFamilyTest, CreateAndDestoryOptions) {
+  std::unique_ptr<ColumnFamilyOptions> cfo(new ColumnFamilyOptions());
+  ColumnFamilyHandle* cfh;
+  Open();
+  ASSERT_OK(db_->CreateColumnFamily(*(cfo.get()), "yoyo", &cfh));
+  cfo.reset();
+  ASSERT_OK(db_->Put(WriteOptions(), cfh, "foo", "bar"));
+  ASSERT_OK(db_->Flush(FlushOptions(), cfh));
+  ASSERT_OK(db_->DropColumnFamily(cfh));
+  ASSERT_OK(db_->DestroyColumnFamilyHandle(cfh));
+}
+
+TEST_F(ColumnFamilyTest, CreateDropAndDestroy) {
+  ColumnFamilyHandle* cfh;
+  Open();
+  ASSERT_OK(db_->CreateColumnFamily(ColumnFamilyOptions(), "yoyo", &cfh));
+  ASSERT_OK(db_->Put(WriteOptions(), cfh, "foo", "bar"));
+  ASSERT_OK(db_->Flush(FlushOptions(), cfh));
+  ASSERT_OK(db_->DropColumnFamily(cfh));
+  ASSERT_OK(db_->DestroyColumnFamilyHandle(cfh));
+}
+
+TEST_F(ColumnFamilyTest, CreateDropAndDestroyWithoutFileDeletion) {
+  ColumnFamilyHandle* cfh;
+  Open();
+  ASSERT_OK(db_->CreateColumnFamily(ColumnFamilyOptions(), "yoyo", &cfh));
+  ASSERT_OK(db_->Put(WriteOptions(), cfh, "foo", "bar"));
+  ASSERT_OK(db_->Flush(FlushOptions(), cfh));
+  ASSERT_OK(db_->DisableFileDeletions());
+  ASSERT_OK(db_->DropColumnFamily(cfh));
+  ASSERT_OK(db_->DestroyColumnFamilyHandle(cfh));
+}
+
 #ifndef ROCKSDB_LITE
 TEST_F(ColumnFamilyTest, FlushCloseWALFiles) {
   SpecialEnv env(Env::Default());

db/compact_files_test.cc

@@ -318,7 +318,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as DBImpl::CompactFiles is not supported in ROCKSDB_LITE\n");
   return 0;

db/compaction_job_stats_test.cc

@@ -1034,7 +1034,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED, not supported in ROCKSDB_LITE\n");
   return 0;
 }
@@ -1043,5 +1043,5 @@ int main(int argc, char** argv) {
 
 #else
 
-int main(int argc, char** argv) { return 0; }
+int main(int /*argc*/, char** /*argv*/) { return 0; }
 #endif  // !defined(IOS_CROSS_COMPILE)

db/compaction_job_test.cc

@@ -946,7 +946,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as CompactionJobStats is not supported in ROCKSDB_LITE\n");
   return 0;

db/corruption_test.cc

@@ -510,7 +510,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as RepairDB() is not supported in ROCKSDB_LITE\n");
   return 0;
 }

db/cuckoo_table_db_test.cc

@@ -333,7 +333,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as Cuckoo table is not supported in ROCKSDB_LITE\n");
   return 0;
 }

db/db_compaction_test.cc

@@ -3482,6 +3482,8 @@ int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 #else
+  (void) argc;
+  (void) argv;
   return 0;
 #endif
 }

db/db_dynamic_level_test.cc

@@ -501,6 +501,8 @@ int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 #else
+  (void) argc;
+  (void) argv;
   return 0;
 #endif
 }

db/db_log_iter_test.cc

@@ -289,6 +289,8 @@ int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 #else
+  (void) argc;
+  (void) argv;
   return 0;
 #endif
 }

db/db_tailing_iter_test.cc

@@ -809,6 +809,8 @@ int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 #else
+  (void) argc;
+  (void) argv;
   return 0;
 #endif
 }

db/db_universal_compaction_test.cc

@@ -1759,6 +1759,8 @@ int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 #else
+  (void) argc;
+  (void) argv;
   return 0;
 #endif
 }

db/deletefile_test.cc

@@ -500,7 +500,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as DBImpl::DeleteFile is not supported in ROCKSDB_LITE\n");
   return 0;

db/external_sst_file_ingestion_job.cc

@@ -510,6 +510,9 @@ Status ExternalSstFileIngestionJob::AssignGlobalSeqnoForIngestedFile(
   std::string seqno_val;
   PutFixed64(&seqno_val, seqno);
   status = rwfile->Write(file_to_ingest->global_seqno_offset, seqno_val);
+  if (status.ok()) {
+    status = rwfile->Fsync();
+  }
   if (status.ok()) {
     file_to_ingest->assigned_seqno = seqno;
   }

db/external_sst_file_test.cc

@@ -2002,7 +2002,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as External SST File Writer and Ingestion are not supported "
           "in ROCKSDB_LITE\n");

db/options_file_test.cc

@@ -112,7 +112,7 @@ int main(int argc, char** argv) {
 
 #include <cstdio>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   printf("Skipped as Options file is not supported in RocksDBLite.\n");
   return 0;
 }

db/plain_table_db_test.cc

@@ -1170,7 +1170,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as plain table is not supported in ROCKSDB_LITE\n");
   return 0;
 }

db/prefix_test.cc

@@ -887,7 +887,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as HashSkipList and HashLinkList are not supported in "
           "ROCKSDB_LITE\n");

db/repair_test.cc

@@ -356,7 +356,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as RepairDB is not supported in ROCKSDB_LITE\n");
   return 0;
 }

db/wal_manager_test.cc

@@ -303,7 +303,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as WalManager is not supported in ROCKSDB_LITE\n");
   return 0;
 }

db/write_callback_test.cc

@@ -431,7 +431,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as WriteWithCallback is not supported in ROCKSDB_LITE\n");
   return 0;

env/env_posix.cc

@@ -802,6 +802,15 @@ class PosixEnv : public Env {
 #endif
   }
 
+  virtual void LowerThreadPoolCPUPriority(Priority pool = LOW) override {
+    assert(pool >= Priority::BOTTOM && pool <= Priority::HIGH);
+#ifdef OS_LINUX
+    thread_pools_[pool].LowerCPUPriority();
+#else
+    (void)pool;
+#endif
+  }
+
   virtual std::string TimeToString(uint64_t secondsSince1970) override {
     const time_t seconds = (time_t)secondsSince1970;
     struct tm t;

env/io_posix.cc

@@ -873,8 +873,12 @@ void PosixWritableFile::SetWriteLifeTimeHint(Env::WriteLifeTimeHint hint) {
   if (fcntl(fd_, F_SET_RW_HINT, &hint) == 0) {
     write_hint_ = hint;
   }
-#endif
-#endif
+#else
+  (void)hint;
+#endif // ROCKSDB_VALGRIND_RUN
+#else
+  (void)hint;
+#endif // OS_LINUX
 }
 
 Status PosixWritableFile::InvalidateCache(size_t offset, size_t length) {

include/rocksdb/advanced_options.h

@@ -87,6 +87,14 @@ struct CompactionOptionsFIFO {
 
 // Compression options for different compression algorithms like Zlib
 struct CompressionOptions {
+  // RocksDB's generic default compression level. Internally it'll be translated
+  // to the default compression level specific to the library being used (see
+  // comment above `ColumnFamilyOptions::compression`).
+  //
+  // The default value is the max 16-bit int as it'll be written out in OPTIONS
+  // file, which should be portable.
+  const static int kDefaultCompressionLevel = 32767;
+
   int window_bits;
   int level;
   int strategy;
@@ -120,7 +128,7 @@ struct CompressionOptions {
 
   CompressionOptions()
       : window_bits(-14),
-        level(-1),
+        level(kDefaultCompressionLevel),
         strategy(0),
         max_dict_bytes(0),
         zstd_max_train_bytes(0) {}

include/rocksdb/env.h

@@ -391,6 +391,9 @@ class Env {
   // Lower IO priority for threads from the specified pool.
   virtual void LowerThreadPoolIOPriority(Priority /*pool*/ = LOW) {}
 
+  // Lower CPU priority for threads from the specified pool.
+  virtual void LowerThreadPoolCPUPriority(Priority /*pool*/ = LOW) {}
+
   // Converts seconds-since-Jan-01-1970 to a printable string
   virtual std::string TimeToString(uint64_t time) = 0;
 
@@ -1082,6 +1085,10 @@ class EnvWrapper : public Env {
     target_->LowerThreadPoolIOPriority(pool);
   }
 
+  void LowerThreadPoolCPUPriority(Priority pool = LOW) override {
+    target_->LowerThreadPoolCPUPriority(pool);
+  }
+
   std::string TimeToString(uint64_t time) override {
     return target_->TimeToString(time);
   }

include/rocksdb/options.h

@@ -197,11 +197,21 @@ struct ColumnFamilyOptions : public AdvancedColumnFamilyOptions {
   // Typical speeds of kSnappyCompression on an Intel(R) Core(TM)2 2.4GHz:
   //    ~200-500MB/s compression
   //    ~400-800MB/s decompression
+  //
   // Note that these speeds are significantly faster than most
   // persistent storage speeds, and therefore it is typically never
   // worth switching to kNoCompression.  Even if the input data is
   // incompressible, the kSnappyCompression implementation will
   // efficiently detect that and will switch to uncompressed mode.
+  //
+  // If you do not set `compression_opts.level`, or set it to
+  // `CompressionOptions::kDefaultCompressionLevel`, we will attempt to pick the
+  // default corresponding to `compression` as follows:
+  //
+  // - kZSTD: 3
+  // - kZlibCompression: Z_DEFAULT_COMPRESSION (currently -1)
+  // - kLZ4HCCompression: 0
+  // - For all others, we do not specify a compression level
   CompressionType compression;
 
   // Compression algorithm that will be used for the bottommost level that

include/rocksdb/version.h

@@ -5,8 +5,8 @@
 #pragma once
 
 #define ROCKSDB_MAJOR 5
-#define ROCKSDB_MINOR 12
-#define ROCKSDB_PATCH 0
+#define ROCKSDB_MINOR 13
+#define ROCKSDB_PATCH 3
 
 // Do not use these. We made the mistake of declaring macros starting with
 // double underscore. Now we have to live with our choice. We'll deprecate these

java/rocksjni/table.cc

@@ -38,13 +38,14 @@ jlong Java_org_rocksdb_PlainTableConfig_newTableFactoryHandle(
 /*
  * Class:     org_rocksdb_BlockBasedTableConfig
  * Method:    newTableFactoryHandle
- * Signature: (ZJIJIIZIZZZJIBBI)J
+ * Signature: (ZJIJJIIZIZZZJIBBI)J
  */
 jlong Java_org_rocksdb_BlockBasedTableConfig_newTableFactoryHandle(
-    JNIEnv* env, jobject jobj, jboolean no_block_cache, jlong block_cache_size,
-    jint block_cache_num_shardbits, jlong block_size, jint block_size_deviation,
-    jint block_restart_interval, jboolean whole_key_filtering,
-    jlong jfilterPolicy, jboolean cache_index_and_filter_blocks,
+    JNIEnv *env, jobject jobj, jboolean no_block_cache, jlong block_cache_size,
+    jint block_cache_num_shardbits, jlong jblock_cache, jlong block_size,
+    jint block_size_deviation, jint block_restart_interval,
+    jboolean whole_key_filtering, jlong jfilter_policy,
+    jboolean cache_index_and_filter_blocks,
     jboolean pin_l0_filter_and_index_blocks_in_cache,
     jboolean hash_index_allow_collision, jlong block_cache_compressed_size,
     jint block_cache_compressd_num_shard_bits, jbyte jchecksum_type,
@@ -52,22 +53,28 @@ jlong Java_org_rocksdb_BlockBasedTableConfig_newTableFactoryHandle(
   rocksdb::BlockBasedTableOptions options;
   options.no_block_cache = no_block_cache;
 
-  if (!no_block_cache && block_cache_size > 0) {
-    if (block_cache_num_shardbits > 0) {
-      options.block_cache =
-          rocksdb::NewLRUCache(block_cache_size, block_cache_num_shardbits);
-    } else {
-      options.block_cache = rocksdb::NewLRUCache(block_cache_size);
+  if (!no_block_cache) {
+    if (jblock_cache > 0) {
+      std::shared_ptr<rocksdb::Cache> *pCache =
+          reinterpret_cast<std::shared_ptr<rocksdb::Cache> *>(jblock_cache);
+      options.block_cache = *pCache;
+    } else if (block_cache_size > 0) {
+      if (block_cache_num_shardbits > 0) {
+        options.block_cache =
+            rocksdb::NewLRUCache(block_cache_size, block_cache_num_shardbits);
+      } else {
+        options.block_cache = rocksdb::NewLRUCache(block_cache_size);
+      }
     }
   }
   options.block_size = block_size;
   options.block_size_deviation = block_size_deviation;
   options.block_restart_interval = block_restart_interval;
   options.whole_key_filtering = whole_key_filtering;
-  if (jfilterPolicy > 0) {
+  if (jfilter_policy > 0) {
     std::shared_ptr<rocksdb::FilterPolicy> *pFilterPolicy =
         reinterpret_cast<std::shared_ptr<rocksdb::FilterPolicy> *>(
-            jfilterPolicy);
+            jfilter_policy);
     options.filter_policy = *pFilterPolicy;
   }
   options.cache_index_and_filter_blocks = cache_index_and_filter_blocks;

java/rocksjni/transaction_db.cc

@@ -304,11 +304,14 @@ jobject Java_org_rocksdb_TransactionDB_getLockStatusData(
       return nullptr;
   }
 
-  const rocksdb::HashMapJni::FnMapKV<const int32_t, const rocksdb::KeyLockInfo> fn_map_kv =
-      [env, txn_db, &lock_status_data](const std::pair<const int32_t, const rocksdb::KeyLockInfo>& pair) {
-          const jobject jlong_column_family_id =
-              rocksdb::LongJni::valueOf(env, pair.first);
-          if (jlong_column_family_id == nullptr) {
+  const rocksdb::HashMapJni::FnMapKV<const int32_t, const rocksdb::KeyLockInfo>
+      fn_map_kv =
+          [env](
+              const std::pair<const int32_t, const rocksdb::KeyLockInfo>&
+                  pair) {
+            const jobject jlong_column_family_id =
+                rocksdb::LongJni::valueOf(env, pair.first);
+            if (jlong_column_family_id == nullptr) {
               // an error occurred
               return std::unique_ptr<std::pair<jobject, jobject>>(nullptr);
           }

java/src/main/java/org/rocksdb/BlockBasedTableConfig.java

@@ -15,6 +15,7 @@ public class BlockBasedTableConfig extends TableFormatConfig {
     noBlockCache_ = false;
     blockCacheSize_ = 8 * 1024 * 1024;
     blockCacheNumShardBits_ = 0;
+    blockCache_ = null;
     blockSize_ = 4 * 1024;
     blockSizeDeviation_ = 10;
     blockRestartInterval_ = 16;
@@ -71,6 +72,24 @@ public class BlockBasedTableConfig extends TableFormatConfig {
     return blockCacheSize_;
   }
 
+  /**
+   * Use the specified cache for blocks.
+   * When not null this take precedence even if the user sets a block cache size.
+   *
+   * {@link org.rocksdb.Cache} should not be disposed before options instances
+   * using this cache is disposed.
+   *
+   * {@link org.rocksdb.Cache} instance can be re-used in multiple options
+   * instances.
+   *
+   * @param cache {@link org.rocksdb.Cache} Cache java instance (e.g. LRUCache).
+   * @return the reference to the current config.
+   */
+  public BlockBasedTableConfig setBlockCache(final Cache cache) {
+    blockCache_ = cache;
+    return this;
+  }
+
   /**
    * Controls the number of shards for the block cache.
    * This is applied only if cacheSize is set to non-negative.
@@ -413,25 +432,25 @@ public class BlockBasedTableConfig extends TableFormatConfig {
       filterHandle = filter_.nativeHandle_;
     }
 
-    return newTableFactoryHandle(noBlockCache_, blockCacheSize_,
-        blockCacheNumShardBits_, blockSize_, blockSizeDeviation_,
-        blockRestartInterval_, wholeKeyFiltering_,
-        filterHandle, cacheIndexAndFilterBlocks_,
-        pinL0FilterAndIndexBlocksInCache_,
-        hashIndexAllowCollision_, blockCacheCompressedSize_,
-        blockCacheCompressedNumShardBits_,
-        checksumType_.getValue(), indexType_.getValue(),
+    long blockCacheHandle = 0;
+    if (blockCache_ != null) {
+      blockCacheHandle = blockCache_.nativeHandle_;
+    }
+
+    return newTableFactoryHandle(noBlockCache_, blockCacheSize_, blockCacheNumShardBits_,
+        blockCacheHandle, blockSize_, blockSizeDeviation_, blockRestartInterval_,
+        wholeKeyFiltering_, filterHandle, cacheIndexAndFilterBlocks_,
+        pinL0FilterAndIndexBlocksInCache_, hashIndexAllowCollision_, blockCacheCompressedSize_,
+        blockCacheCompressedNumShardBits_, checksumType_.getValue(), indexType_.getValue(),
         formatVersion_);
   }
 
-  private native long newTableFactoryHandle(
-      boolean noBlockCache, long blockCacheSize, int blockCacheNumShardBits,
-      long blockSize, int blockSizeDeviation, int blockRestartInterval,
-      boolean wholeKeyFiltering, long filterPolicyHandle,
+  private native long newTableFactoryHandle(boolean noBlockCache, long blockCacheSize,
+      int blockCacheNumShardBits, long blockCacheHandle, long blockSize, int blockSizeDeviation,
+      int blockRestartInterval, boolean wholeKeyFiltering, long filterPolicyHandle,
       boolean cacheIndexAndFilterBlocks, boolean pinL0FilterAndIndexBlocksInCache,
       boolean hashIndexAllowCollision, long blockCacheCompressedSize,
-      int blockCacheCompressedNumShardBits, byte checkSumType,
-      byte indexType, int formatVersion);
+      int blockCacheCompressedNumShardBits, byte checkSumType, byte indexType, int formatVersion);
 
   private boolean cacheIndexAndFilterBlocks_;
   private boolean pinL0FilterAndIndexBlocksInCache_;
@@ -442,6 +461,7 @@ public class BlockBasedTableConfig extends TableFormatConfig {
   private long blockSize_;
   private long blockCacheSize_;
   private int blockCacheNumShardBits_;
+  private Cache blockCache_;
   private long blockCacheCompressedSize_;
   private int blockCacheCompressedNumShardBits_;
   private int blockSizeDeviation_;

java/src/test/java/org/rocksdb/BlockBasedTableConfigTest.java

@@ -6,7 +6,11 @@
 package org.rocksdb;
 
 import org.junit.ClassRule;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import java.nio.charset.StandardCharsets;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -16,6 +20,8 @@ public class BlockBasedTableConfigTest {
   public static final RocksMemoryResource rocksMemoryResource =
       new RocksMemoryResource();
 
+  @Rule public TemporaryFolder dbFolder = new TemporaryFolder();
+
   @Test
   public void noBlockCache() {
     BlockBasedTableConfig blockBasedTableConfig = new BlockBasedTableConfig();
@@ -31,6 +37,31 @@ public class BlockBasedTableConfigTest {
         isEqualTo(8 * 1024);
   }
 
+  @Test
+  public void sharedBlockCache() throws RocksDBException {
+    try (final Cache cache = new LRUCache(8 * 1024 * 1024);
+         final Statistics statistics = new Statistics()) {
+      for (int shard = 0; shard < 8; shard++) {
+        try (final Options options =
+                 new Options()
+                     .setCreateIfMissing(true)
+                     .setStatistics(statistics)
+                     .setTableFormatConfig(new BlockBasedTableConfig().setBlockCache(cache));
+             final RocksDB db =
+                 RocksDB.open(options, dbFolder.getRoot().getAbsolutePath() + "/" + shard)) {
+          final byte[] key = "some-key".getBytes(StandardCharsets.UTF_8);
+          final byte[] value = "some-value".getBytes(StandardCharsets.UTF_8);
+
+          db.put(key, value);
+          db.flush(new FlushOptions());
+          db.get(key);
+
+          assertThat(statistics.getTickerCount(TickerType.BLOCK_CACHE_ADD)).isEqualTo(shard + 1);
+        }
+      }
+    }
+  }
+
   @Test
   public void blockSizeDeviation() {
     BlockBasedTableConfig blockBasedTableConfig = new BlockBasedTableConfig();
@@ -148,6 +179,14 @@ public class BlockBasedTableConfigTest {
     }
   }
 
+  @Test
+  public void blockBasedTableWithBlockCache() {
+    try (final Options options = new Options().setTableFormatConfig(
+             new BlockBasedTableConfig().setBlockCache(new LRUCache(17 * 1024 * 1024)))) {
+      assertThat(options.tableFactoryName()).isEqualTo("BlockBasedTable");
+    }
+  }
+
   @Test
   public void blockBasedTableFormatVersion() {
     BlockBasedTableConfig config = new BlockBasedTableConfig();

table/block_based_filter_block.cc

@@ -67,7 +67,8 @@ BlockBasedFilterBlockBuilder::BlockBasedFilterBlockBuilder(
       prefix_extractor_(prefix_extractor),
       whole_key_filtering_(table_opt.whole_key_filtering),
       prev_prefix_start_(0),
-      prev_prefix_size_(0) {
+      prev_prefix_size_(0),
+      num_added_(0) {
   assert(policy_);
 }
 
@@ -91,6 +92,7 @@ void BlockBasedFilterBlockBuilder::Add(const Slice& key) {
 
 // Add key to filter if needed
 inline void BlockBasedFilterBlockBuilder::AddKey(const Slice& key) {
+  num_added_++;
   start_.push_back(entries_.size());
   entries_.append(key.data(), key.size());
 }
@@ -106,10 +108,9 @@ inline void BlockBasedFilterBlockBuilder::AddPrefix(const Slice& key) {
   Slice prefix = prefix_extractor_->Transform(key);
   // insert prefix only when it's different from the previous prefix.
   if (prev.size() == 0 || prefix != prev) {
-    start_.push_back(entries_.size());
+    AddKey(prefix);
     prev_prefix_start_ = entries_.size();
     prev_prefix_size_ = prefix.size();
-    entries_.append(prefix.data(), prefix.size());
   }
 }
 

table/block_based_filter_block.h

@@ -41,6 +41,7 @@ class BlockBasedFilterBlockBuilder : public FilterBlockBuilder {
   virtual bool IsBlockBased() override { return true; }
   virtual void StartBlock(uint64_t block_offset) override;
   virtual void Add(const Slice& key) override;
+  virtual size_t NumAdded() const override { return num_added_; }
   virtual Slice Finish(const BlockHandle& tmp, Status* status) override;
   using FilterBlockBuilder::Finish;
 
@@ -65,6 +66,7 @@ class BlockBasedFilterBlockBuilder : public FilterBlockBuilder {
   std::string result_;              // Filter data computed so far
   std::vector<Slice> tmp_entries_;  // policy_->CreateFilter() argument
   std::vector<uint32_t> filter_offsets_;
+  size_t num_added_;                // Number of keys added
 
   // No copying allowed
   BlockBasedFilterBlockBuilder(const BlockBasedFilterBlockBuilder&);

table/block_based_filter_block_test.cc

@@ -65,6 +65,7 @@ TEST_F(FilterBlockTest, EmptyBuilder) {
 
 TEST_F(FilterBlockTest, SingleChunk) {
   BlockBasedFilterBlockBuilder builder(nullptr, table_options_);
+  ASSERT_EQ(0, builder.NumAdded());
   builder.StartBlock(100);
   builder.Add("foo");
   builder.Add("bar");
@@ -73,6 +74,7 @@ TEST_F(FilterBlockTest, SingleChunk) {
   builder.Add("box");
   builder.StartBlock(300);
   builder.Add("hello");
+  ASSERT_EQ(5, builder.NumAdded());
   BlockContents block(builder.Finish(), false, kNoCompression);
   BlockBasedFilterBlockReader reader(nullptr, table_options_, true,
                                      std::move(block), nullptr);

table/block_based_table_builder.cc

@@ -650,8 +650,11 @@ Status BlockBasedTableBuilder::Finish() {
 
   BlockHandle filter_block_handle, metaindex_block_handle, index_block_handle,
       compression_dict_block_handle, range_del_block_handle;
+
   // Write filter block
-  if (ok() && r->filter_builder != nullptr) {
+  bool empty_filter_block = (r->filter_builder == nullptr ||
+                             r->filter_builder->NumAdded() == 0);
+  if (ok() && !empty_filter_block) {
     Status s = Status::Incomplete();
     while (s.IsIncomplete()) {
       Slice filter_content = r->filter_builder->Finish(filter_block_handle, &s);
@@ -687,7 +690,7 @@ Status BlockBasedTableBuilder::Finish() {
   }
 
   if (ok()) {
-    if (r->filter_builder != nullptr) {
+    if (!empty_filter_block) {
       // Add mapping from "<filter_block_prefix>.Name" to location
       // of filter data.
       std::string key;

table/block_based_table_reader.cc

@@ -120,7 +120,7 @@ void ReleaseCachedEntry(void* arg, void* h) {
 void ForceReleaseCachedEntry(void* arg, void* h) {
   Cache* cache = reinterpret_cast<Cache*>(arg);
   Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
-  cache->Release(handle, true);
+  cache->Release(handle, true /* force_erase */);
 }
 
 Slice GetCacheKeyFromOffset(const char* cache_key_prefix,

table/block_based_table_reader.h

@@ -419,7 +419,7 @@ struct BlockBasedTable::Rep {
 
   const ImmutableCFOptions& ioptions;
   const EnvOptions& env_options;
-  const BlockBasedTableOptions& table_options;
+  const BlockBasedTableOptions table_options;
   const FilterPolicy* const filter_policy;
   const InternalKeyComparator& internal_comparator;
   Status status;

table/cuckoo_table_builder_test.cc

@@ -625,7 +625,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as Cuckoo table is not supported in ROCKSDB_LITE\n");
   return 0;
 }

table/cuckoo_table_reader_test.cc

@@ -560,7 +560,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as Cuckoo table is not supported in ROCKSDB_LITE\n");
   return 0;
 }

table/filter_block.h

@@ -51,6 +51,7 @@ class FilterBlockBuilder {
   virtual bool IsBlockBased() = 0;                    // If is blockbased filter
   virtual void StartBlock(uint64_t block_offset) = 0;  // Start new block filter
   virtual void Add(const Slice& key) = 0;      // Add a key to current filter
+  virtual size_t NumAdded() const = 0;         // Number of keys added
   Slice Finish() {                             // Generate Filter
     const BlockHandle empty_handle;
     Status dont_care_status;

table/full_filter_block.h

@@ -45,6 +45,7 @@ class FullFilterBlockBuilder : public FilterBlockBuilder {
   virtual bool IsBlockBased() override { return false; }
   virtual void StartBlock(uint64_t /*block_offset*/) override {}
   virtual void Add(const Slice& key) override;
+  virtual size_t NumAdded() const override { return num_added_; }
   virtual Slice Finish(const BlockHandle& tmp, Status* status) override;
   using FilterBlockBuilder::Finish;
 

table/full_filter_block_test.cc

@@ -163,11 +163,13 @@ TEST_F(FullFilterBlockTest, EmptyBuilder) {
 TEST_F(FullFilterBlockTest, SingleChunk) {
   FullFilterBlockBuilder builder(
       nullptr, true, table_options_.filter_policy->GetFilterBitsBuilder());
+  ASSERT_EQ(0, builder.NumAdded());
   builder.Add("foo");
   builder.Add("bar");
   builder.Add("box");
   builder.Add("box");
   builder.Add("hello");
+  ASSERT_EQ(5, builder.NumAdded());
   Slice block = builder.Finish();
   FullFilterBlockReader reader(
       nullptr, true, block,

table/partitioned_filter_block.cc

@@ -25,7 +25,8 @@ PartitionedFilterBlockBuilder::PartitionedFilterBlockBuilder(
                              filter_bits_builder),
       index_on_filter_block_builder_(index_block_restart_interval),
       p_index_builder_(p_index_builder),
-      filters_in_partition_(0) {
+      filters_in_partition_(0),
+      num_added_(0) {
   filters_per_partition_ =
       filter_bits_builder_->CalculateNumEntry(partition_size);
 }
@@ -53,6 +54,7 @@ void PartitionedFilterBlockBuilder::AddKey(const Slice& key) {
   MaybeCutAFilterBlock();
   filter_bits_builder_->AddKey(key);
   filters_in_partition_++;
+  num_added_++;
 }
 
 Slice PartitionedFilterBlockBuilder::Finish(
@@ -244,6 +246,13 @@ size_t PartitionedFilterBlockReader::ApproximateMemoryUsage() const {
   return idx_on_fltr_blk_->size();
 }
 
+// Release the cached entry and decrement its ref count.
+void ReleaseFilterCachedEntry(void* arg, void* h) {
+  Cache* cache = reinterpret_cast<Cache*>(arg);
+  Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
+  cache->Release(handle);
+}
+
 // TODO(myabandeh): merge this with the same function in IndexReader
 void PartitionedFilterBlockReader::CacheDependencies(bool pin) {
   // Before read partitions, prefetch them to avoid lots of IOs
@@ -302,6 +311,8 @@ void PartitionedFilterBlockReader::CacheDependencies(bool pin) {
     if (LIKELY(filter.IsSet())) {
       if (pin) {
         filter_map_[handle.offset()] = std::move(filter);
+        RegisterCleanup(&ReleaseFilterCachedEntry, block_cache,
+                        filter.cache_handle);
       } else {
         block_cache->Release(filter.cache_handle);
       }

table/partitioned_filter_block.h

@@ -33,6 +33,8 @@ class PartitionedFilterBlockBuilder : public FullFilterBlockBuilder {
 
   void AddKey(const Slice& key) override;
 
+  size_t NumAdded() const override { return num_added_; }
+
   virtual Slice Finish(const BlockHandle& last_partition_block_handle,
                        Status* status) override;
 
@@ -59,9 +61,12 @@ class PartitionedFilterBlockBuilder : public FullFilterBlockBuilder {
   uint32_t filters_per_partition_;
   // The current number of filters in the last partition
   uint32_t filters_in_partition_;
+  // Number of keys added
+  size_t num_added_;
 };
 
-class PartitionedFilterBlockReader : public FilterBlockReader {
+class PartitionedFilterBlockReader : public FilterBlockReader,
+                                     public Cleanable {
  public:
   explicit PartitionedFilterBlockReader(const SliceTransform* prefix_extractor,
                                         bool whole_key_filtering,

table/table_test.cc

@@ -302,9 +302,11 @@ class KeyConvertingIterator : public InternalIterator {
 class TableConstructor: public Constructor {
  public:
   explicit TableConstructor(const Comparator* cmp,
-                            bool convert_to_internal_key = false)
+                            bool convert_to_internal_key = false,
+                            int level = -1)
       : Constructor(cmp),
-        convert_to_internal_key_(convert_to_internal_key) {}
+        convert_to_internal_key_(convert_to_internal_key),
+        level_(level) {}
   ~TableConstructor() { Reset(); }
 
   virtual Status FinishImpl(const Options& options,
@@ -319,14 +321,12 @@ class TableConstructor: public Constructor {
     std::vector<std::unique_ptr<IntTblPropCollectorFactory>>
         int_tbl_prop_collector_factories;
     std::string column_family_name;
-    int unknown_level = -1;
     builder.reset(ioptions.table_factory->NewTableBuilder(
-        TableBuilderOptions(ioptions, internal_comparator,
-                            &int_tbl_prop_collector_factories,
-                            options.compression, CompressionOptions(),
-                            nullptr /* compression_dict */,
-                            false /* skip_filters */, column_family_name,
-                            unknown_level),
+        TableBuilderOptions(
+            ioptions, internal_comparator, &int_tbl_prop_collector_factories,
+            options.compression, CompressionOptions(),
+            nullptr /* compression_dict */, false /* skip_filters */,
+            column_family_name, level_),
         TablePropertiesCollectorFactory::Context::kUnknownColumnFamily,
         file_writer_.get()));
 
@@ -351,8 +351,10 @@ class TableConstructor: public Constructor {
     uniq_id_ = cur_uniq_id_++;
     file_reader_.reset(test::GetRandomAccessFileReader(new test::StringSource(
         GetSink()->contents(), uniq_id_, ioptions.allow_mmap_reads)));
+    const bool skip_filters = false;
     return ioptions.table_factory->NewTableReader(
-        TableReaderOptions(ioptions, soptions, internal_comparator),
+        TableReaderOptions(ioptions, soptions, internal_comparator,
+                           skip_filters, level_),
         std::move(file_reader_), GetSink()->contents().size(), &table_reader_);
   }
 
@@ -412,6 +414,7 @@ class TableConstructor: public Constructor {
   unique_ptr<RandomAccessFileReader> file_reader_;
   unique_ptr<TableReader> table_reader_;
   bool convert_to_internal_key_;
+  int level_;
 
   TableConstructor();
 
@@ -2249,6 +2252,7 @@ std::map<std::string, size_t> MockCache::marked_data_in_cache_;
 // table is closed. This test makes sure that the only items remains in the
 // cache after the table is closed are raw data blocks.
 TEST_F(BlockBasedTableTest, NoObjectInCacheAfterTableClose) {
+  for (int level: {-1, 0, 1, 10}) {
   for (auto index_type :
        {BlockBasedTableOptions::IndexType::kBinarySearch,
         BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch}) {
@@ -2285,7 +2289,9 @@ TEST_F(BlockBasedTableTest, NoObjectInCacheAfterTableClose) {
                 rocksdb::NewBloomFilterPolicy(10, block_based_filter));
             opt.table_factory.reset(NewBlockBasedTableFactory(table_options));
 
-            TableConstructor c(BytewiseComparator());
+            bool convert_to_internal_key = false;
+            TableConstructor c(BytewiseComparator(), convert_to_internal_key,
+                               level);
             std::string user_key = "k01";
             std::string key =
                 InternalKey(user_key, 0, kTypeValue).Encode().ToString();
@@ -2326,6 +2332,7 @@ TEST_F(BlockBasedTableTest, NoObjectInCacheAfterTableClose) {
       }
     }
   }
+  } // level
 }
 
 TEST_F(BlockBasedTableTest, BlockCacheLeak) {

table/two_level_iterator.cc

@@ -24,7 +24,11 @@ class TwoLevelIterator : public InternalIterator {
   explicit TwoLevelIterator(TwoLevelIteratorState* state,
                             InternalIterator* first_level_iter);
 
-  virtual ~TwoLevelIterator() { delete state_; }
+  virtual ~TwoLevelIterator() {
+    first_level_iter_.DeleteIter(false /* is_arena_mode */);
+    second_level_iter_.DeleteIter(false /* is_arena_mode */);
+    delete state_;
+  }
 
   virtual void Seek(const Slice& target) override;
   virtual void SeekForPrev(const Slice& target) override;

table/two_level_iterator.h

@@ -16,8 +16,8 @@ namespace rocksdb {
 
 struct ReadOptions;
 class InternalKeyComparator;
-class Arena;
 
+// TwoLevelIteratorState expects iterators are not created using the arena
 struct TwoLevelIteratorState {
   TwoLevelIteratorState() {}
 
@@ -35,11 +35,7 @@ struct TwoLevelIteratorState {
 //
 // Uses a supplied function to convert an index_iter value into
 // an iterator over the contents of the corresponding block.
-// arena: If not null, the arena is used to allocate the Iterator.
-//        When destroying the iterator, the destructor will destroy
-//        all the states but those allocated in arena.
-// need_free_iter_and_state: free `state` and `first_level_iter` if
-//                           true. Otherwise, just call destructor.
+// Note: this function expects first_level_iter was not created using the arena
 extern InternalIterator* NewTwoLevelIterator(
     TwoLevelIteratorState* state, InternalIterator* first_level_iter);
 

tools/db_bench_tool.cc

@@ -989,6 +989,8 @@ DEFINE_int32(memtable_insert_with_hint_prefix_size, 0,
              "memtable insert with hint with the given prefix size.");
 DEFINE_bool(enable_io_prio, false, "Lower the background flush/compaction "
             "threads' IO priority");
+DEFINE_bool(enable_cpu_prio, false, "Lower the background flush/compaction "
+            "threads' CPU priority");
 DEFINE_bool(identity_as_first_hash, false, "the first hash function of cuckoo "
             "table becomes an identity function. This is only valid when key "
             "is 8 bytes");
@@ -2941,6 +2943,8 @@ void VerifyDBFromDB(std::string& truth_db_name) {
               FLAGS_options_file.c_str(), s.ToString().c_str());
       exit(1);
     }
+#else
+    (void)opts;
 #endif
     return false;
   }
@@ -3315,6 +3319,10 @@ void VerifyDBFromDB(std::string& truth_db_name) {
       FLAGS_env->LowerThreadPoolIOPriority(Env::LOW);
       FLAGS_env->LowerThreadPoolIOPriority(Env::HIGH);
     }
+    if (FLAGS_enable_cpu_prio) {
+      FLAGS_env->LowerThreadPoolCPUPriority(Env::LOW);
+      FLAGS_env->LowerThreadPoolCPUPriority(Env::HIGH);
+    }
     options.env = FLAGS_env;
 
     if (FLAGS_rate_limiter_bytes_per_sec > 0) {
@@ -3996,6 +4004,9 @@ void VerifyDBFromDB(std::string& truth_db_name) {
     }
     return Status::OK();
 #else
+    (void)thread;
+    (void)compaction_style;
+    (void)write_mode;
     fprintf(stderr, "Rocksdb Lite doesn't support filldeterministic\n");
     return Status::NotSupported(
         "Rocksdb Lite doesn't support filldeterministic");

tools/db_stress.cc

@@ -1021,9 +1021,7 @@ class DbStressListener : public EventListener {
       : db_name_(db_name), db_paths_(db_paths) {}
   virtual ~DbStressListener() {}
 #ifndef ROCKSDB_LITE
-  virtual void OnFlushCompleted(DB* db, const FlushJobInfo& info) override {
-    assert(db);
-    assert(db->GetName() == db_name_);
+  virtual void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
     assert(IsValidColumnFamilyName(info.cf_name));
     VerifyFilePath(info.file_path);
     // pretending doing some work here
@@ -1031,10 +1029,8 @@ class DbStressListener : public EventListener {
         std::chrono::microseconds(Random::GetTLSInstance()->Uniform(5000)));
   }
 
-  virtual void OnCompactionCompleted(DB* db,
+  virtual void OnCompactionCompleted(DB* /*db*/,
                                      const CompactionJobInfo& ci) override {
-    assert(db);
-    assert(db->GetName() == db_name_);
     assert(IsValidColumnFamilyName(ci.cf_name));
     assert(ci.input_files.size() + ci.output_files.size() > 0U);
     for (const auto& file_path : ci.input_files) {
@@ -1086,6 +1082,8 @@ class DbStressListener : public EventListener {
       }
     }
     assert(false);
+#else
+    (void)file_dir;
 #endif  // !NDEBUG
   }
 
@@ -1096,6 +1094,8 @@ class DbStressListener : public EventListener {
     bool result = ParseFileName(file_name, &file_number, &file_type);
     assert(result);
     assert(file_type == kTableFile);
+#else
+    (void)file_name;
 #endif  // !NDEBUG
   }
 
@@ -1110,6 +1110,8 @@ class DbStressListener : public EventListener {
       }
       VerifyFileName(file_path.substr(pos));
     }
+#else
+    (void)file_path;
 #endif  // !NDEBUG
   }
 #endif  // !ROCKSDB_LITE
@@ -2289,6 +2291,7 @@ class StressTest {
     size_t value_sz =
         ((rand % kRandomValueMaxFactor) + 1) * FLAGS_value_size_mult;
     assert(value_sz <= max_sz && value_sz >= sizeof(uint32_t));
+    (void) max_sz;
     *((uint32_t*)v) = rand;
     for (size_t i=sizeof(uint32_t); i < value_sz; i++) {
       v[i] = (char)(rand ^ i);

tools/ldb_cmd_test.cc

@@ -54,7 +54,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as LDBCommand is not supported in ROCKSDB_LITE\n");
   return 0;
 }

tools/reduce_levels_test.cc

@@ -210,7 +210,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as LDBCommand is not supported in ROCKSDB_LITE\n");
   return 0;
 }

tools/sst_dump_test.cc

@@ -215,7 +215,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as SSTDumpTool is not supported in ROCKSDB_LITE\n");
   return 0;
 }

util/auto_roll_logger_test.cc

@@ -520,7 +520,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as AutoRollLogger is not supported in ROCKSDB_LITE\n");
   return 0;

util/autovector_test.cc

@@ -27,6 +27,9 @@ template <class T>
 void AssertAutoVectorOnlyInStack(autovector<T, kSize>* vec, bool result) {
 #ifndef ROCKSDB_LITE
   ASSERT_EQ(vec->only_in_stack(), result);
+#else
+  (void) vec;
+  (void) result;
 #endif  // !ROCKSDB_LITE
 }
 }  // namespace

util/compression.h

@@ -246,9 +246,15 @@ inline bool Zlib_Compress(const CompressionOptions& opts,
   // memLevel=9 uses maximum memory for optimal speed.
   // The default value is 8. See zconf.h for more details.
   static const int memLevel = 8;
+  int level;
+  if (opts.level == CompressionOptions::kDefaultCompressionLevel) {
+    level = Z_DEFAULT_COMPRESSION;
+  } else {
+    level = opts.level;
+  }
   z_stream _stream;
   memset(&_stream, 0, sizeof(z_stream));
-  int st = deflateInit2(&_stream, opts.level, Z_DEFLATED, opts.window_bits,
+  int st = deflateInit2(&_stream, level, Z_DEFLATED, opts.window_bits,
                         memLevel, opts.strategy);
   if (st != Z_OK) {
     return false;
@@ -682,9 +688,15 @@ inline bool LZ4HC_Compress(const CompressionOptions& opts,
   output->resize(static_cast<size_t>(output_header_len + compress_bound));
 
   int outlen;
+  int level;
+  if (opts.level == CompressionOptions::kDefaultCompressionLevel) {
+    level = 0;  // lz4hc.h says any value < 1 will be sanitized to default
+  } else {
+    level = opts.level;
+  }
 #if LZ4_VERSION_NUMBER >= 10400  // r124+
   LZ4_streamHC_t* stream = LZ4_createStreamHC();
-  LZ4_resetStreamHC(stream, opts.level);
+  LZ4_resetStreamHC(stream, level);
   const char* compression_dict_data =
       compression_dict.size() > 0 ? compression_dict.data() : nullptr;
   size_t compression_dict_size = compression_dict.size();
@@ -705,7 +717,7 @@ inline bool LZ4HC_Compress(const CompressionOptions& opts,
 #elif LZ4_VERSION_MAJOR  // r113-r123
   outlen = LZ4_compressHC2_limitedOutput(input, &(*output)[output_header_len],
                                          static_cast<int>(length),
-                                         compress_bound, opts.level);
+                                         compress_bound, level);
 #else                    // up to r112
   outlen =
       LZ4_compressHC_limitedOutput(input, &(*output)[output_header_len],
@@ -766,15 +778,23 @@ inline bool ZSTD_Compress(const CompressionOptions& opts, const char* input,
   size_t compressBound = ZSTD_compressBound(length);
   output->resize(static_cast<size_t>(output_header_len + compressBound));
   size_t outlen;
+  int level;
+  if (opts.level == CompressionOptions::kDefaultCompressionLevel) {
+    // 3 is the value of ZSTD_CLEVEL_DEFAULT (not exposed publicly), see
+    // https://github.com/facebook/zstd/issues/1148
+    level = 3;
+  } else {
+    level = opts.level;
+  }
 #if ZSTD_VERSION_NUMBER >= 500  // v0.5.0+
   ZSTD_CCtx* context = ZSTD_createCCtx();
   outlen = ZSTD_compress_usingDict(
       context, &(*output)[output_header_len], compressBound, input, length,
-      compression_dict.data(), compression_dict.size(), opts.level);
+      compression_dict.data(), compression_dict.size(), level);
   ZSTD_freeCCtx(context);
 #else  // up to v0.4.x
   outlen = ZSTD_compress(&(*output)[output_header_len], compressBound, input,
-                         length, opts.level);
+                         length, level);
 #endif  // ZSTD_VERSION_NUMBER >= 500
   if (outlen == 0) {
     return false;

util/delete_scheduler_test.cc

@@ -613,7 +613,7 @@ int main(int argc, char** argv) {
 }
 
 #else
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   printf("DeleteScheduler is not supported in ROCKSDB_LITE\n");
   return 0;
 }

util/threadpool_imp.cc

@@ -18,6 +18,7 @@
 
 #ifdef OS_LINUX
 #  include <sys/syscall.h>
+#  include <sys/resource.h>
 #endif
 
 #include <algorithm>
@@ -53,6 +54,8 @@ struct ThreadPoolImpl::Impl {
 
   void LowerIOPriority();
 
+  void LowerCPUPriority();
+
   void WakeUpAllThreads() {
     bgsignal_.notify_all();
   }
@@ -97,6 +100,7 @@ private:
   static void* BGThreadWrapper(void* arg);
 
   bool low_io_priority_;
+  bool low_cpu_priority_;
   Env::Priority priority_;
   Env*         env_;
 
@@ -125,6 +129,7 @@ inline
 ThreadPoolImpl::Impl::Impl()
     :
       low_io_priority_(false),
+      low_cpu_priority_(false),
       priority_(Env::LOW),
       env_(nullptr),
       total_threads_limit_(0),
@@ -171,9 +176,16 @@ void ThreadPoolImpl::Impl::LowerIOPriority() {
   low_io_priority_ = true;
 }
 
+inline
+void ThreadPoolImpl::Impl::LowerCPUPriority() {
+  std::lock_guard<std::mutex> lock(mu_);
+  low_cpu_priority_ = true;
+}
 
 void ThreadPoolImpl::Impl::BGThread(size_t thread_id) {
   bool low_io_priority = false;
+  bool low_cpu_priority = false;
+
   while (true) {
 // Wait until there is an item that is ready to run
     std::unique_lock<std::mutex> lock(mu_);
@@ -213,9 +225,20 @@ void ThreadPoolImpl::Impl::BGThread(size_t thread_id) {
                      std::memory_order_relaxed);
 
     bool decrease_io_priority = (low_io_priority != low_io_priority_);
+    bool decrease_cpu_priority = (low_cpu_priority != low_cpu_priority_);
     lock.unlock();
 
 #ifdef OS_LINUX
+    if (decrease_cpu_priority) {
+      setpriority(
+          PRIO_PROCESS,
+          // Current thread.
+          0,
+          // Lowest priority possible.
+          19);
+      low_cpu_priority = true;
+    }
+
     if (decrease_io_priority) {
 #define IOPRIO_CLASS_SHIFT (13)
 #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
@@ -236,6 +259,7 @@ void ThreadPoolImpl::Impl::BGThread(size_t thread_id) {
     }
 #else
     (void)decrease_io_priority;  // avoid 'unused variable' error
+    (void)decrease_cpu_priority;
 #endif
     func();
   }
@@ -421,6 +445,10 @@ void ThreadPoolImpl::LowerIOPriority() {
   impl_->LowerIOPriority();
 }
 
+void ThreadPoolImpl::LowerCPUPriority() {
+  impl_->LowerCPUPriority();
+}
+
 void ThreadPoolImpl::IncBackgroundThreadsIfNeeded(int num) {
   impl_->SetBackgroundThreadsInternal(num, false);
 }

util/threadpool_imp.h

@@ -46,10 +46,14 @@ class ThreadPoolImpl : public ThreadPool {
   // start yet
   void WaitForJobsAndJoinAllThreads() override;
 
-  // Make threads to run at a lower kernel priority
+  // Make threads to run at a lower kernel IO priority
   // Currently only has effect on Linux
   void LowerIOPriority();
 
+  // Make threads to run at a lower kernel CPU priority
+  // Currently only has effect on Linux
+  void LowerCPUPriority();
+
   // Ensure there is at aleast num threads in the pool
   // but do not kill threads if there are more
   void IncBackgroundThreadsIfNeeded(int num);

utilities/backupable/backupable_db.cc

@@ -747,6 +747,19 @@ Status BackupEngineImpl::CreateNewBackupWithMetadata(
   BackupID new_backup_id = latest_backup_id_ + 1;
 
   assert(backups_.find(new_backup_id) == backups_.end());
+
+  auto private_dir = GetAbsolutePath(GetPrivateFileRel(new_backup_id));
+  Status s = backup_env_->FileExists(private_dir);
+  if (s.ok()) {
+    // maybe last backup failed and left partial state behind, clean it up.
+    // need to do this before updating backups_ such that a private dir
+    // named after new_backup_id will be cleaned up
+    s = GarbageCollect();
+  } else if (s.IsNotFound()) {
+    // normal case, the new backup's private dir doesn't exist yet
+    s = Status::OK();
+  }
+
   auto ret = backups_.insert(std::make_pair(
       new_backup_id, unique_ptr<BackupMeta>(new BackupMeta(
                          GetBackupMetaFile(new_backup_id, false /* tmp */),
@@ -757,23 +770,13 @@ Status BackupEngineImpl::CreateNewBackupWithMetadata(
   new_backup->RecordTimestamp();
   new_backup->SetAppMetadata(app_metadata);
 
-  auto start_backup = backup_env_-> NowMicros();
+  auto start_backup = backup_env_->NowMicros();
 
   ROCKS_LOG_INFO(options_.info_log,
                  "Started the backup process -- creating backup %u",
                  new_backup_id);
-
-  auto private_tmp_dir = GetAbsolutePath(GetPrivateFileRel(new_backup_id, true));
-  Status s = backup_env_->FileExists(private_tmp_dir);
   if (s.ok()) {
-    // maybe last backup failed and left partial state behind, clean it up
-    s = GarbageCollect();
-  } else if (s.IsNotFound()) {
-    // normal case, the new backup's private dir doesn't exist yet
-    s = Status::OK();
-  }
-  if (s.ok()) {
-    s = backup_env_->CreateDir(private_tmp_dir);
+    s = backup_env_->CreateDir(private_dir);
   }
 
   RateLimiter* rate_limiter = options_.backup_rate_limiter.get();
@@ -859,18 +862,6 @@ Status BackupEngineImpl::CreateNewBackupWithMetadata(
   // we copied all the files, enable file deletions
   db->EnableFileDeletions(false);
 
-  if (s.ok()) {
-    // move tmp private backup to real backup folder
-    ROCKS_LOG_INFO(
-        options_.info_log,
-        "Moving tmp backup directory to the real one: %s -> %s\n",
-        GetAbsolutePath(GetPrivateFileRel(new_backup_id, true)).c_str(),
-        GetAbsolutePath(GetPrivateFileRel(new_backup_id, false)).c_str());
-    s = backup_env_->RenameFile(
-        GetAbsolutePath(GetPrivateFileRel(new_backup_id, true)),  // tmp
-        GetAbsolutePath(GetPrivateFileRel(new_backup_id, false)));
-  }
-
   auto backup_time = backup_env_->NowMicros() - start_backup;
 
   if (s.ok()) {
@@ -1307,22 +1298,33 @@ Status BackupEngineImpl::AddBackupFileWorkItem(
     dst_relative_tmp = GetSharedFileRel(dst_relative, true);
     dst_relative = GetSharedFileRel(dst_relative, false);
   } else {
-    dst_relative_tmp = GetPrivateFileRel(backup_id, true, dst_relative);
     dst_relative = GetPrivateFileRel(backup_id, false, dst_relative);
   }
-  std::string dst_path = GetAbsolutePath(dst_relative);
-  std::string dst_path_tmp = GetAbsolutePath(dst_relative_tmp);
+
+  // We copy into `temp_dest_path` and, once finished, rename it to
+  // `final_dest_path`. This allows files to atomically appear at
+  // `final_dest_path`. We can copy directly to the final path when atomicity
+  // is unnecessary, like for files in private backup directories.
+  const std::string* copy_dest_path;
+  std::string temp_dest_path;
+  std::string final_dest_path = GetAbsolutePath(dst_relative);
+  if (!dst_relative_tmp.empty()) {
+    temp_dest_path = GetAbsolutePath(dst_relative_tmp);
+    copy_dest_path = &temp_dest_path;
+  } else {
+    copy_dest_path = &final_dest_path;
+  }
 
   // if it's shared, we also need to check if it exists -- if it does, no need
   // to copy it again.
   bool need_to_copy = true;
-  // true if dst_path is the same path as another live file
+  // true if final_dest_path is the same path as another live file
   const bool same_path =
-      live_dst_paths.find(dst_path) != live_dst_paths.end();
+      live_dst_paths.find(final_dest_path) != live_dst_paths.end();
 
   bool file_exists = false;
   if (shared && !same_path) {
-    Status exist = backup_env_->FileExists(dst_path);
+    Status exist = backup_env_->FileExists(final_dest_path);
     if (exist.ok()) {
       file_exists = true;
     } else if (exist.IsNotFound()) {
@@ -1351,7 +1353,7 @@ Status BackupEngineImpl::AddBackupFileWorkItem(
           "overwrite the file.",
           fname.c_str());
       need_to_copy = true;
-      backup_env_->DeleteFile(dst_path);
+      backup_env_->DeleteFile(final_dest_path);
     } else {
       // the file is present and referenced by a backup
       ROCKS_LOG_INFO(options_.info_log,
@@ -1360,25 +1362,25 @@ Status BackupEngineImpl::AddBackupFileWorkItem(
                             &checksum_value);
     }
   }
-  live_dst_paths.insert(dst_path);
+  live_dst_paths.insert(final_dest_path);
 
   if (!contents.empty() || need_to_copy) {
     ROCKS_LOG_INFO(options_.info_log, "Copying %s to %s", fname.c_str(),
-                   dst_path_tmp.c_str());
+                   copy_dest_path->c_str());
     CopyOrCreateWorkItem copy_or_create_work_item(
-        src_dir.empty() ? "" : src_dir + fname, dst_path_tmp, contents, db_env_,
-        backup_env_, options_.sync, rate_limiter, size_limit,
+        src_dir.empty() ? "" : src_dir + fname, *copy_dest_path, contents,
+        db_env_, backup_env_, options_.sync, rate_limiter, size_limit,
         progress_callback);
     BackupAfterCopyOrCreateWorkItem after_copy_or_create_work_item(
         copy_or_create_work_item.result.get_future(), shared, need_to_copy,
-        backup_env_, dst_path_tmp, dst_path, dst_relative);
+        backup_env_, temp_dest_path, final_dest_path, dst_relative);
     files_to_copy_or_create_.write(std::move(copy_or_create_work_item));
     backup_items_to_finish.push_back(std::move(after_copy_or_create_work_item));
   } else {
     std::promise<CopyOrCreateResult> promise_result;
     BackupAfterCopyOrCreateWorkItem after_copy_or_create_work_item(
         promise_result.get_future(), shared, need_to_copy, backup_env_,
-        dst_path_tmp, dst_path, dst_relative);
+        temp_dest_path, final_dest_path, dst_relative);
     backup_items_to_finish.push_back(std::move(after_copy_or_create_work_item));
     CopyOrCreateResult result;
     result.status = s;
@@ -1533,7 +1535,7 @@ Status BackupEngineImpl::GarbageCollect() {
     }
     // here we have to delete the dir and all its children
     std::string full_private_path =
-        GetAbsolutePath(GetPrivateFileRel(backup_id, tmp_dir));
+        GetAbsolutePath(GetPrivateFileRel(backup_id));
     std::vector<std::string> subchildren;
     backup_env_->GetChildren(full_private_path, &subchildren);
     for (auto& subchild : subchildren) {

utilities/backupable/backupable_db_test.cc

@@ -811,9 +811,8 @@ TEST_F(BackupableDBTest, NoDoubleCopy) {
   test_db_env_->SetFilenamesForMockedAttrs(dummy_db_->live_files_);
   ASSERT_OK(backup_engine_->CreateNewBackup(db_.get(), false));
   std::vector<std::string> should_have_written = {
-      "/shared/.00010.sst.tmp",   "/shared/.00011.sst.tmp",
-      "/private/1.tmp/CURRENT",   "/private/1.tmp/MANIFEST-01",
-      "/private/1.tmp/00011.log", "/meta/.1.tmp"};
+      "/shared/.00010.sst.tmp", "/shared/.00011.sst.tmp", "/private/1/CURRENT",
+      "/private/1/MANIFEST-01", "/private/1/00011.log",   "/meta/.1.tmp"};
   AppendPath(backupdir_, should_have_written);
   test_backup_env_->AssertWrittenFiles(should_have_written);
 
@@ -829,9 +828,9 @@ TEST_F(BackupableDBTest, NoDoubleCopy) {
   ASSERT_OK(backup_engine_->CreateNewBackup(db_.get(), false));
   // should not open 00010.sst - it's already there
 
-  should_have_written = {"/shared/.00015.sst.tmp", "/private/2.tmp/CURRENT",
-                         "/private/2.tmp/MANIFEST-01",
-                         "/private/2.tmp/00011.log", "/meta/.2.tmp"};
+  should_have_written = {"/shared/.00015.sst.tmp", "/private/2/CURRENT",
+                         "/private/2/MANIFEST-01", "/private/2/00011.log",
+                         "/meta/.2.tmp"};
   AppendPath(backupdir_, should_have_written);
   test_backup_env_->AssertWrittenFiles(should_have_written);
 
@@ -976,7 +975,7 @@ TEST_F(BackupableDBTest, InterruptCreationTest) {
       backup_engine_->CreateNewBackup(db_.get(), !!(rnd.Next() % 2)).ok());
   CloseDBAndBackupEngine();
   // should also fail cleanup so the tmp directory stays behind
-  ASSERT_OK(backup_chroot_env_->FileExists(backupdir_ + "/private/1.tmp/"));
+  ASSERT_OK(backup_chroot_env_->FileExists(backupdir_ + "/private/1/"));
 
   OpenDBAndBackupEngine(false /* destroy_old_data */);
   test_backup_env_->SetLimitWrittenFiles(1000000);
@@ -1171,7 +1170,7 @@ TEST_F(BackupableDBTest, DeleteTmpFiles) {
       shared_tmp += "/shared";
     }
     shared_tmp += "/.00006.sst.tmp";
-    std::string private_tmp_dir = backupdir_ + "/private/10.tmp";
+    std::string private_tmp_dir = backupdir_ + "/private/10";
     std::string private_tmp_file = private_tmp_dir + "/00003.sst";
     file_manager_->WriteToFile(shared_tmp, "tmp");
     file_manager_->CreateDir(private_tmp_dir);
@@ -1589,7 +1588,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as BackupableDB is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/blob_db/blob_db_test.cc

@@ -1524,7 +1524,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as BlobDB is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/checkpoint/checkpoint_test.cc

@@ -584,7 +584,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as Checkpoint is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/column_aware_encoding_exp.cc

@@ -169,7 +169,7 @@ int main() {
 }
 #endif  // GFLAGS
 #else
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "Not supported in lite mode.\n");
   return 1;
 }

utilities/date_tiered/date_tiered_test.cc

@@ -460,7 +460,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as DateTieredDB is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/document/document_db_test.cc

@@ -328,7 +328,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as DocumentDB is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/document/json_document_test.cc

@@ -333,7 +333,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as JSONDocument is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/env_timed_test.cc

@@ -36,7 +36,7 @@ int main(int argc, char** argv) {
 #else  // ROCKSDB_LITE
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as TimedEnv is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/lua/rocks_lua_test.cc

@@ -491,7 +491,7 @@ int main(int argc, char** argv) {
 
 #else
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   printf("Lua is not supported in RocksDBLite.  Ignoring the test.\n");
 }
 

utilities/memory/memory_test.cc

@@ -269,7 +269,7 @@ int main(int argc, char** argv) {
 #else
 #include <cstdio>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   printf("Skipped in RocksDBLite as utilities are not supported.\n");
   return 0;
 }

utilities/object_registry_test.cc

@@ -65,7 +65,7 @@ int main(int argc, char** argv) {
 #else  // ROCKSDB_LITE
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as EnvRegistry is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/options/options_util_test.cc

@@ -311,7 +311,7 @@ int main(int argc, char** argv) {
 #else
 #include <cstdio>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   printf("Skipped in RocksDBLite as utilities are not supported.\n");
   return 0;
 }

utilities/redis/redis_lists_test.cc

@@ -886,7 +886,7 @@ int main(int argc, char* argv[]) {
 #else
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as redis is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/spatialdb/spatial_db_test.cc

@@ -299,7 +299,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as SpatialDB is not supported in ROCKSDB_LITE\n");
   return 0;
 }

utilities/table_properties_collectors/compact_on_deletion_collector_test.cc

@@ -171,7 +171,7 @@ int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "PASSED\n");
 }
 #else
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as RocksDBLite does not include utilities.\n");
   return 0;
 }

utilities/transactions/optimistic_transaction_test.cc

@@ -1391,7 +1391,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(
       stderr,
       "SKIPPED as optimistic_transaction is not supported in ROCKSDB_LITE\n");

utilities/transactions/transaction_test.cc

@@ -5542,7 +5542,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as Transactions are not supported in ROCKSDB_LITE\n");
   return 0;

utilities/transactions/write_prepared_transaction_test.cc

@@ -2003,7 +2003,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as Transactions are not supported in ROCKSDB_LITE\n");
   return 0;

utilities/ttl/ttl_test.cc

@@ -655,7 +655,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr, "SKIPPED as DBWithTTL is not supported in ROCKSDB_LITE\n");
   return 0;
 }