RocksDBLite

Summary:
Introducing RocksDBLite! Removes all the non-essential features and reduces the binary size. This effort should help our adoption on mobile.

Binary size when compiling for IOS (`TARGET_OS=IOS m static_lib`) is down to 9MB from 15MB (without stripping)

Test Plan: compiles :)

Reviewers: dhruba, haobo, ljin, sdong, yhchiang

Reviewed By: yhchiang

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17835

include/rocksdb/db.h

@@ -381,6 +381,11 @@ class DB {
     return Flush(options, DefaultColumnFamily());
   }
 
+  // The sequence number of the most recent transaction.
+  virtual SequenceNumber GetLatestSequenceNumber() const = 0;
+
+#ifndef ROCKSDB_LITE
+
   // Prevent file deletions. Compactions will continue to occur,
   // but no obsolete files will be deleted. Calling this multiple
   // times have the same effect as calling it once.
@@ -422,9 +427,6 @@ class DB {
   // Retrieve the sorted list of all wal files with earliest file first
   virtual Status GetSortedWalFiles(VectorLogPtr& files) = 0;
 
-  // The sequence number of the most recent transaction.
-  virtual SequenceNumber GetLatestSequenceNumber() const = 0;
-
   // Sets iter to an iterator that is positioned at a write-batch containing
   // seq_number. If the sequence number is non existent, it returns an iterator
   // at the first available seq_no after the requested seq_no
@@ -447,6 +449,8 @@ class DB {
   // and end key
   virtual void GetLiveFilesMetaData(std::vector<LiveFileMetaData>* metadata) {}
 
+#endif  // ROCKSDB_LITE
+
   // Sets the globally unique ID created at database creation time by invoking
   // Env::GenerateUniqueId(), in identity. Returns Status::OK if identity could
   // be set properly
@@ -455,11 +459,13 @@ class DB {
   // Returns default column family handle
   virtual ColumnFamilyHandle* DefaultColumnFamily() const = 0;
 
+#ifndef ROCKSDB_LITE
   virtual Status GetPropertiesOfAllTables(ColumnFamilyHandle* column_family,
                                           TablePropertiesCollection* props) = 0;
   Status GetPropertiesOfAllTables(TablePropertiesCollection* props) {
     return GetPropertiesOfAllTables(DefaultColumnFamily(), props);
   }
+#endif  // ROCKSDB_LITE
 
  private:
   // No copying allowed
@@ -471,11 +477,13 @@ class DB {
 // Be very careful using this method.
 Status DestroyDB(const std::string& name, const Options& options);
 
+#ifndef ROCKSDB_LITE
 // If a DB cannot be opened, you may attempt to call this method to
 // resurrect as much of the contents of the database as possible.
 // Some data may be lost, so be careful when calling this function
 // on a database that contains important information.
 Status RepairDB(const std::string& dbname, const Options& options);
+#endif
 
 }  // namespace rocksdb
 

include/rocksdb/ldb_tool.h

@@ -2,8 +2,8 @@
 // This source code is licensed under the BSD-style license found in the
 // LICENSE file in the root directory of this source tree. An additional grant
 // of patent rights can be found in the PATENTS file in the same directory.
-#ifndef STORAGE_ROCKSDB_INCLUDE_LDB_TOOL_H
-#define STORAGE_ROCKSDB_INCLUDE_LDB_TOOL_H
+#ifndef ROCKSDB_LITE
+#pragma once
 #include "rocksdb/options.h"
 
 namespace rocksdb {
@@ -15,4 +15,4 @@ class LDBTool {
 
 } // namespace rocksdb
 
-#endif // STORAGE_ROCKSDB_INCLUDE_LDB_TOOL_H
+#endif  // ROCKSDB_LITE

include/rocksdb/memtablerep.h

@@ -177,6 +177,16 @@ class MemTableRepFactory {
   virtual const char* Name() const = 0;
 };
 
+// This uses a skip list to store keys. It is the default.
+class SkipListFactory : public MemTableRepFactory {
+ public:
+  virtual MemTableRep* CreateMemTableRep(const MemTableRep::KeyComparator&,
+                                         Arena*,
+                                         const SliceTransform*) override;
+  virtual const char* Name() const override { return "SkipListFactory"; }
+};
+
+#ifndef ROCKSDB_LITE
 // This creates MemTableReps that are backed by an std::vector. On iteration,
 // the vector is sorted. This is useful for workloads where iteration is very
 // rare and writes are generally not issued after reads begin.
@@ -198,17 +208,6 @@ class VectorRepFactory : public MemTableRepFactory {
   }
 };
 
-// This uses a skip list to store keys. It is the default.
-class SkipListFactory : public MemTableRepFactory {
- public:
-  virtual MemTableRep* CreateMemTableRep(
-      const MemTableRep::KeyComparator&, Arena*,
-      const SliceTransform*) override;
-  virtual const char* Name() const override {
-    return "SkipListFactory";
-  }
-};
-
 // This class contains a fixed array of buckets, each
 // pointing to a skiplist (null if the bucket is empty).
 // bucket_count: number of fixed array buckets
@@ -227,4 +226,6 @@ extern MemTableRepFactory* NewHashSkipListRepFactory(
 extern MemTableRepFactory* NewHashLinkListRepFactory(
     size_t bucket_count = 50000);
 
+#endif  // ROCKSDB_LITE
+
 }  // namespace rocksdb

include/rocksdb/options.h

@@ -850,6 +850,7 @@ struct ReadOptions {
   // added data) and is optimized for sequential reads. It will return records
   // that were inserted into the database after the creation of the iterator.
   // Default: false
+  // Not supported in ROCKSDB_LITE mode!
   bool tailing;
 
   ReadOptions()

include/rocksdb/table.h

@@ -81,6 +81,7 @@ struct BlockBasedTablePropertyNames {
 extern TableFactory* NewBlockBasedTableFactory(
     const BlockBasedTableOptions& table_options = BlockBasedTableOptions());
 
+#ifndef ROCKSDB_LITE
 // -- Plain Table with prefix-only seek
 // For this factory, you need to set Options.prefix_extrator properly to make it
 // work. Look-up will starts with prefix hash lookup for key prefix. Inside the
@@ -120,6 +121,8 @@ extern TableFactory* NewTotalOrderPlainTableFactory(
     uint32_t user_key_len = kPlainTableVariableLength,
     int bloom_bits_per_key = 0, size_t index_sparseness = 16);
 
+#endif  // ROCKSDB_LITE
+
 // A base class for table factories.
 class TableFactory {
  public:

include/utilities/backupable_db.h

@@ -7,6 +7,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
+#ifndef ROCKSDB_LITE
 #pragma once
 #include "utilities/stackable_db.h"
 #include "rocksdb/env.h"
@@ -210,3 +211,4 @@ class RestoreBackupableDB {
 };
 
 } // rocksdb namespace
+#endif  // ROCKSDB_LITE

include/utilities/geo_db.h

@@ -4,6 +4,7 @@
 //  of patent rights can be found in the PATENTS file in the same directory.
 //
 
+#ifndef ROCKSDB_LITE
 #pragma once
 #include <string>
 #include <vector>
@@ -101,3 +102,4 @@ class GeoDB : public StackableDB {
 };
 
 }  // namespace rocksdb
+#endif  // ROCKSDB_LITE

include/utilities/utility_db.h

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
+#ifndef ROCKSDB_LITE
 #pragma once
 #include "stackable_db.h"
 
@@ -48,3 +49,4 @@ class UtilityDB {
 };
 
 } //  namespace rocksdb
+#endif  // ROCKSDB_LITE