Release RocksDB 4.8.0

Summary: Release RocksDB 4.8.0

Test Plan: N/A

Reviewers: sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57525

DEFAULT_OPTIONS_HISTORY.md

@@ -1,9 +1,9 @@
-## Unreleased
+# RocksDB default options change log
+## 4.8.0 (5/2/2016)
 * options.max_open_files changes from 5000 to -1. It improves performance, but users need to set file descriptor limit to be large enough and watch memory usage for index and bloom filters.
 * options.base_background_compactions changes from max_background_compactions to 1. When users set higher max_background_compactions but the write throughput is not high, the writes are less spiky to disks.
 * options.wal_recovery_mode changes from kTolerateCorruptedTailRecords to kPointInTimeRecovery. Avoid some false positive when file system or hardware reorder the writes for file data and metadata.
 
-# RocksDB default options change log
 ## 4.7.0 (4/8/2016)
 * options.write_buffer_size changes from 4MB to 64MB.
 * options.target_file_size_base changes from 2MB to 64MB.

HISTORY.md

@@ -1,5 +1,5 @@
 # Rocksdb Change Log
-## Unreleased
+## 4.8.0 (5/2/2016)
 ### Public API Change
 * Allow preset compression dictionary for improved compression of block-based tables. This is supported for zlib, zstd, and lz4. The compression dictionary's size is configurable via CompressionOptions::max_dict_bytes.
 * Delete deprecated classes for creating backups (BackupableDB) and restoring from backups (RestoreBackupableDB). Now, BackupEngine should be used for creating backups, and BackupEngineReadOnly should be used for restorations. For more details, see https://github.com/facebook/rocksdb/wiki/How-to-backup-RocksDB%3F

include/rocksdb/version.h

@@ -5,7 +5,7 @@
 #pragma once
 
 #define ROCKSDB_MAJOR 4
-#define ROCKSDB_MINOR 7
+#define ROCKSDB_MINOR 8
 #define ROCKSDB_PATCH 0
 
 // Do not use these. We made the mistake of declaring macros starting with