Summary:
Fixed a bug in Compaction.cc where input_levels_ was not properly resized.
Without this fix, there would be invalid access in input_levels_ when more
than two levels are involved in one compaction run.

This fix will go to master instead of compaction branch.

Test Plan: tested in compaction branch.

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20481

Summary:
All public headers need to be under `include/rocksdb` directory. Otherwise, clients include our header files like this:

    #include <rocksdb/db.h>
    #include <utilities/backupable_db.h> // still our public header!

Also, internally, we include:

    #include "utilities/backupable/backupable_db.h" // internal header
    #include "utilities/backupable_db.h" // public header

which is confusing.

This way, when we install rocksdb as a system library, we can just copy `include/rocksdb` directory to system's header files. We can't really copy `utilities` directory to system's header files.

Test Plan: compiles

Reviewers: dhruba, ljin, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20409

Summary:
Add a function GetOptions(), where based on four parameters users give: read/write amplification threshold, memory budget for mem tables and target DB size, it picks up a compaction style and parameters for them. Background threads are not touched yet.

One limit of this algorithm: since compression rate and key/value size are hard to predict, it's hard to predict level 0 file size from write buffer size. Simply make 1:1 ratio here.

Sample results: https://reviews.facebook.net/P477

Test Plan: Will add some a unit test where some sample scenarios are given and see they pick the results that make sense

Reviewers: yhchiang, dhruba, haobo, igor, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D18741

Summary:
This diff merges pull request 208.  Contributor: ankgup87

[Java] Optimize statistics collector
* Optimize statistics collector by collecting statistics of multiple DBs in a single thread rather than starting up a new thread for each DB.
* Also, fix packaging of jnilib file on OS_X platform.
* Diff review: https://reviews.facebook.net/D20265

[Java] Add documentation on interdependency of dispose call of RocksObjects
* Remove transferCppRawPointersOwnershipFrom function.
  - This function was setting opt.filter_ and thus filter_ to be null. This way there is no
    one holding reference for filter object and can thus be GC'd which is not the intention.
    Replaced it with storeOptionsInstace which stores options instance. Options class
    internally holds Filter instance. Thus when Options is GC'd, filter reference
    will be GC'd automatically.
* Added documentation explaining interdependency of Filter, Options and DB.
* Diff review: https://reviews.facebook.net/D20379

Test Plan:
described in their diff reviews

Reviewers:  haobo sdong swapnilghike zzbennett rsumbaly yhchiang

Reviewed by: yhchiang

Summary:
This diff merges pull request #208.  Contributor: ankgup87

[Java] Optimize statistics collector
* Optimize statistics collector by collecting statistics of multiple DBs in a single thread rather than starting up a new thread for each DB.
* Also, fix packaging of jnilib file on OS_X platform.
* Diff review: https://reviews.facebook.net/D20265

[Java] Add documentation on interdependency of dispose call of RocksObjects
* Remove transferCppRawPointersOwnershipFrom function.
  - This function was setting opt.filter_ and thus filter_ to be null. This way there is no
    one holding reference for filter object and can thus be GC'd which is not the intention.
    Replaced it with storeOptionsInstace which stores options instance. Options class
    internally holds Filter instance. Thus when Options is GC'd, filter reference
    will be GC'd automatically.
* Added documentation explaining interdependency of Filter, Options and DB.
* Diff review: https://reviews.facebook.net/D20379

Test Plan:
described in their diff reviews

Reviewers:  haobo sdong swapnilghike zzbennett rsumbaly yhchiang

Reviewed by: yhchiang

Summary: Fixes some memory leaks in cuckoo_builder_test.cc. This also fixed broken valgrind_check tests

Test Plan:
make valgrind_check
./cuckoo_builder_test
Currently running make check all. I shall update once it is done.

Reviewers: ljin, sdong, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20385

Summary:
Add setCacheNumShardBits() and cacheNumShardBits() to Options.  This allows
developers to control the number of shards for the block cache.

Test Plan:
make rocksdbjava
cd java
make db_bench
./jdb_bench.sh --cache_size=1048576 --cache_numshardbits=6

Reviewers: sdong, ljin, ankgup87

Reviewed By: ankgup87

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19347

Summary:
Fixed some make and linking issues of RocksDBJava. Specifically:
* Add JAVA_LDFLAGS, which does not include gflags
* rocksdbjava library now uses JAVA_LDFLAGS instead of LDFLAGS
* java/Makefile now includes build_config.mk
* rearrange make rocksdbjava workflow to ensure the library file is correctly
  included in the jar file.

Test Plan:
make rocksdbjava
make jdb_bench
java/jdb_bench.sh

Reviewers: dhruba, swapnilghike, zzbennett, rsumbaly, ankgup87

Reviewed By: ankgup87

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20289

Summary: Add a parameter path_id to DB::CompactRange(), to indicate where the output file should be placed to.

Test Plan: add a unit test

Reviewers: yhchiang, ljin

Reviewed By: ljin

Subscribers: xjin, igor, dhruba, MarkCallaghan, leveldb

Differential Revision: https://reviews.facebook.net/D20085

Summary:
Fixed the following compile error.

./table/cuckoo_table_builder.h:72:22: error: private field 'key_length_' is not used [-Werror,-Wunused-private-field]
  const unsigned int key_length_;
                     ^
1 error generated.

Test Plan: make

Reviewers: sdong, ljin, radheshyamb, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20349

Summary:
Cuckoo Hashing based SST table builder. Contains:
- Cuckoo Hashing logic and file storage logic.
- Unit tests for logic

Test Plan:
make cuckoo_table_builder_test
./cuckoo_table_builder_test
make check all

Reviewers: yhchiang, igor, sdong, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D19545

Summary:
also make it aware of column family
output from db_bench

```
** Compaction Stats [default] **
Level Files Size(MB) Score Read(GB)  Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) RW-Amp W-Amp Rd(MB/s) Wr(MB/s)  Rn(cnt) Rnp1(cnt) Wnp1(cnt) Wnew(cnt)  Comp(sec) Comp(cnt) Avg(sec) Stall(sec) Stall(cnt) Avg(ms)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  L0    14      956   0.9      0.0     0.0      0.0       2.7      2.7    0.0   0.0      0.0    111.6        0         0         0         0         24        40    0.612      75.20     492387    0.15
  L1    21     2001   2.0      5.7     2.0      3.7       5.3      1.6    5.4   2.6     71.2     65.7       31        43        55        12         82         2   41.242      43.72      41183    1.06
  L2   217    18974   1.9     16.5     2.0     14.4      15.1      0.7   15.6   7.4     70.1     64.3       17       182       185         3        241        16   15.052       0.00          0    0.00
  L3  1641   188245   1.8      9.1     1.1      8.0       8.5      0.5   15.4   7.4     61.3     57.2        9        75        76         1        152         9   16.887       0.00          0    0.00
  L4  4447   449025   0.4     13.4     4.8      8.6       9.1      0.5    4.7   1.9     77.8     52.7       38        79       100        21        176        38    4.639       0.00          0    0.00
 Sum  6340   659201   0.0     44.7    10.0     34.7      40.6      6.0   32.0  15.2     67.7     61.6       95       379       416        37        676       105    6.439     118.91     533570    0.22
 Int     0        0   0.0      1.2     0.4      0.8       1.3      0.5    5.2   2.7     59.1     65.6        3         7         9         2         20        10    2.003       0.00          0    0.00
Stalls(secs): 75.197 level0_slowdown, 0.000 level0_numfiles, 0.000 memtable_compaction, 43.717 leveln_slowdown
Stalls(count): 492387 level0_slowdown, 0 level0_numfiles, 0 memtable_compaction, 41183 leveln_slowdown

** DB Stats **
Uptime(secs): 202.1 total, 13.5 interval
Cumulative writes: 6291456 writes, 6291456 batches, 1.0 writes per batch, 4.90 ingest GB
Cumulative WAL: 6291456 writes, 6291456 syncs, 1.00 writes per sync, 4.90 GB written
Interval writes: 1048576 writes, 1048576 batches, 1.0 writes per batch, 836.0 ingest MB
Interval WAL: 1048576 writes, 1048576 syncs, 1.00 writes per sync, 0.82 MB written

Test Plan: ran it

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19917

Summary:
  Add block_restart_interval in db_bench, default value 16

Test Plan:
  make

Reviewers: sdong

Reviewed By: sdong

Differential Revision: https://reviews.facebook.net/D20331

Summary:
Suggested by @dhruba from the other diff, here is the improved
comments for parameters of the function

Test Plan: none

Reviewers: dhruba, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D19623

Summary: Adding check for zero size index

Test Plan: ./build_tools/regression_build_test.sh

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20259

Summary: Fixed the Java compilation error caused by PlainTableFactory API change.

Test Plan:
make rocksdbjava
make jdb_bench
cd java;./jdb_bench.sh

Reviewers: sdong, ljin, ankgup87, swapnilghike, zzbennett, rsumbaly, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20295

Fix clang compiler warnings

Summary: Updating HISTORY.md to reflect changes in PlainTable index

Test Plan: no need

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20229

Summary:
Adding option to save PlainTable index and bloom filter in SST file.
If there is no bloom block and/or index block, PlainTableReader builds
new ones. Otherwise PlainTableReader just use these blocks.

Test Plan: make all check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19527

Summary:
Since we have a lot of options for PlainTable, add a struct PlainTableOptions
to manage them

Test Plan: make all check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20175

Summary:
Having if-then branch for different compaction strategies is considered
hacky and make CompactionPicker less pluggable.  This diff removes two
of such if-then branches in version_set.cc by adding MaxInputLevel() to
CompactionPicker.

    // Given the current number of levels, returns the lowest allowed level
    // for compaction input.
    virtual int MaxInputLevel(int current_num_levels) const;

Test Plan:
make db_test
export ROCKSDB_TESTS=Compaction
./db_test

Reviewers: igor, sdong, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19971

Summary:
Add -Wsign-compare to WARNING_FLAGS in Makefile as not all g++ compiler
include -Wsign-compare in -Wall when compiling '.h' file.

Test Plan: make -j32

Reviewers: ljin, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D20169

Summary:
Fixed a signed and unsigned comparison in Compaction

Test Plan:
make db_test
export ROCKSDB_TESTS=Compaction
./db_test

Summary: Adding guards to files_ attribute of FilePicker class. This attribute is used only in DEBUG mode. This fixes build of static_lib in mac.

Test Plan:
make static_lib in mac
make check all in devserver

Reviewers: ljin, igor, sdong

Reviewed By: sdong

Differential Revision: https://reviews.facebook.net/D20163

Summary:
Allow class Compaction to handle input files from multiple levels.
This diff is a subset of https://reviews.facebook.net/D19263 where
only db/compaction.cc and db/compaction.h are changed.

Test Plan:
make db_test
export ROCKSDB_TESTS=Compaction
./db_test

Reviewers: igor, sdong, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19923

Summary: Add struct CompactionInputFiles to manage compaction input files.

Test Plan:
export ROCKSDB_TESTS=Compact
make db_test
./db_test

Reviewers: ljin, igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20061

Summary:
  add a flag called use_hash_search in db_bench

Test Plan:
  make all check
  ./db_bench --use_hash_search=1

Reviewers: ljin, haobo, yhchiang, sdong

Reviewed By: sdong

Subscribers: igor, dhruba

Differential Revision: https://reviews.facebook.net/D20067

Summary:
  One line change to fix a bug in the LOG when flush memtable

Test Plan:
  NONE

Reviewers: sdong

Reviewed By: sdong

Differential Revision: https://reviews.facebook.net/D20049

Summary: Added deletion of DBIterators in DBIterator's tests

Test Plan: make valgrind_check

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20043

Summary: Refactoring Version::Get() method to move file picker logic to a separate class.

Test Plan: make check all

Reviewers: igor, sdong, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19713

Summary:
  use arena to allocate space for next_level_index_ and level_rb_
  Thus increasing data locality and make Version::Get faster.

Benchmark detail
Base version: commit d2a727c1

command used:
./db_bench --db=/mnt/db/rocksdb --num_levels=6 --key_size=20 --prefix_size=20 --keys_per_prefix=0 --value_size=100 --block_size=4096 --cache_size=17179869184 --cache_numshardbits=6 --compression_type=none --compression_ratio=1 --min_level_to_compress=-1 --disable_seek_compaction=1 --hard_rate_limit=2 --write_buffer_size=134217728 --max_write_buffer_number=2 --level0_file_num_compaction_trigger=8 --target_file_size_base=2097152 --max_bytes_for_level_base=1073741824 --disable_wal=0 --sync=0 --disable_data_sync=1 --verify_checksum=1 --delete_obsolete_files_period_micros=314572800 --max_grandparent_overlap_factor=10 --max_background_compactions=4 --max_background_flushes=0 --level0_slowdown_writes_trigger=16 --level0_stop_writes_trigger=24 --statistics=0 --stats_per_interval=0 --stats_interval=1048576 --histogram=0 --use_plain_table=1 --open_files=-1 --mmap_read=1 --mmap_write=0 --memtablerep=prefix_hash --bloom_bits=10 --bloom_locality=1 --perf_level=0 --benchmarks=fillseq, readrandom,readrandom,readrandom --use_existing_db=0 --num=52428800 --threads=1

Result:
cpu running percentage:
Version::Get, improved from 7.98% to 7.42%
FileIndexer::GetNextLevelIndex, improved from 1.18% to 0.68%.

Test Plan:
  make all check

Reviewers: ljin, haobo, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, igor

Differential Revision: https://reviews.facebook.net/D19845

Summary: Implement Prev() with merge operator for DBIterator. Request from mongoDB. Task 4673663.

Test Plan: make all check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19743

Summary:
This patch adds a target size parameter in options.db_paths and universal compaction will base it to determine which DB path to place a new file.
Level-style stays the same.

Test Plan: Add new unit tests

Reviewers: ljin, yhchiang

Reviewed By: yhchiang

Subscribers: MarkCallaghan, dhruba, igor, leveldb

Differential Revision: https://reviews.facebook.net/D19869

Summary: Browsing through the code, looks like StatsLogger is not used at all!

Test Plan: compiles

Reviewers: ljin, sdong, yhchiang, dhruba

Reviewed By: dhruba

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D19827

Summary: As title

Test Plan: Not needed for comment only.

Reviewers: yhchiang, ljin, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: xjin, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D19887