Changes to support unity build:
* Script for building the unity.cc file via Makefile
* Unity executable Makefile target for testing builds
* Source code changes to fix compilation of unity build
check prefix_size when using hash search in db_bench

Summary:
1. Check prefix_size when enable use_hash_search in db_bench
2. Remove include/statistics.h in db_bench

Test Plan: ./db_bench --use_hash_search=1

Reviewers: ljin, yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21375
Merge pull request #228 from miguelportilla/develop

Changes to support unity build:

Script for building the unity.cc file via Makefile
Unity executable Makefile target for testing builds
Source code changes to fix compilation of unity build
make statistics ToString function empty instead of pure virtual

Summary: as title

Test Plan: make release

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21549
Integrating Cuckoo Hash SST Table format into RocksDB

Summary:
Contains the following changes:
- Implementation of cuckoo_table_factory
- Adding cuckoo table into AdaptiveTableFactory
- Adding cuckoo_table_db_test, similar to lines of plain_table_db_test
- Minor fixes to Reader: When a key is found in the table, return the key found instead of the search key.
- Minor fixes to Builder: Add table properties that are required by Version::UpdateTemporaryStats() during Get operation. Don't define curr_node as a reference variable as the memory locations may get reassigned during tree.push_back operation, leading to invalid memory access.

Test Plan:
cuckoo_table_reader_test --enable_perf
cuckoo_table_builder_test
cuckoo_table_db_test
make check all
make valgrind_check
make asan_check

Reviewers: sdong, igor, yhchiang, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21219
Flush only one column family

Summary:
Currently DBImpl::Flush() triggers flushes in all column families.
Instead we need to trigger just the column family specified.

Test Plan: make all check

Reviewers: igor, ljin, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20841
Add scope guard

Summary: Small change: replace mutex_.Lock/mutex_.Unlock() with scope guard

Test Plan: make all check

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21609
set bytes_per_sync to 1MB if rate limiter is enabled

Summary: as title

Test Plan: make all check

Reviewers: igor, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21201
remove tailing_iter.h/cc

Summary: as title

Test Plan:
make all check
ran db_bench and saw seek stats at the end

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21651
Fixed a signed-unsigned comparison error in db_test

Summary:
Fixed a signed-unsigned comparison error in db_test

Test Plan:
make db_test
Fixed compile errors (signed / unsigned comparison) in cuckoo_table_db_test on Mac

Summary:
Fixed compile errors (signed / unsigned comparison) in cuckoo_table_db_test on Mac

Test Plan:
make cuckoo_table_db_test
Revert "Include candidate files under options.db_log_dir in FindObsoleteFiles()"

This reverts commit 54153ab07abcd9265a8f4d77d3e984d2932404d0.
Update HISTORY.md
Remove malloc from FormatFileNumber

Summary: Replace unnecessary malloc with stack allocation

Test Plan: make all check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21771
log db path info before open

Summary: 1. write db MANIFEST, CURRENT, IDENTITY, sst files, log files to log before open

Test Plan: run db and check LOG file

Reviewers: ljin, yhchiang, igor, dhruba, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21459
Add histogram for DB_SEEK

Summary: as title

Test Plan: make release

Reviewers: sdong, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21717
print compaction_filter name in Options.Dump

Summary:
Was looking at an issue. All options are the same except
compaction_filter was missed from a newer package. Our option dump does
not capture that

Test Plan: make release

Reviewers: sdong, igor, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21765
fix_valgrind_error_caused_in_db_info_dummper

Summary: 1. add default value to FileType type, thus avoid valgrind error

Test Plan: valgrind ./db_test

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21807
Allow env_posix to lower background thread IO priority

Summary: This is a linux-specific system call.

Test Plan: ran db_bench

Reviewers: igor, yhchiang, sdong

Reviewed By: sdong

Subscribers: haobo, leveldb

Differential Revision: https://reviews.facebook.net/D21183
fix compile error under Mac OS X