Previous to this commit Filters passed as parameters to the
BlockTableConfig are disposed before they should be disposed.
Further Smart pointer usage was corrected.
Java holds now the smart pointer to the FilterPolicy correctly
and cares about freeing underlying c++ structures.
Summary:
Added support for the merge operation to RocksJava.
You can specify a merge function to be used on the current database.
The merge function can either be one of the functions defined in
utilities/merge_operators.h, which can be specified through its
corresponding name, or a user-created function that needs to be
encapsulated in a JNI object in order to be used. Examples are
provided for both use cases.
Test Plan: There are unit test in MergeTest.java
Reviewers: ankgup87
Subscribers: vladb38
Differential Revision: https://reviews.facebook.net/D24525
This commit includes the support for the following functionalities:
- Single Get/Put operations
- WriteBatch operations
- Single iterator functionality
- Open database with column families
- Open database with column families Read/Only
- Create column family
- Drop column family
- Properties of column families
- Listing of column families
- Fully backwards comptabile implementation
- Multi Iterator support
- MultiGet
- KeyMayExist
- Option to create missing column families on open
In addition there is are two new Tests:
- Test of ColumnFamily functionality
- Test of Read only feature to open subsets of column families
- Basic test to test the KeyMayExist feature
What is not supported currently using RocksJava:
- Custom ColumnFamilyOptions
The following targets work as expected:
- make rocksdbjava
- make jtest
Test environment: Ubuntu 14.04(LTS, x64), Java 1.7.0_65(OpenJDK IcedTea 2.5.2), g++ 4.8.2, kernel 3.13.0-35-generix
Summary:
This pull request solves the jlong overflow problem on 32-Bit machines as described in https://github.com/facebook/rocksdb/issues/278:
1. There is a new org.rocksdb.test.PlatformRandomHelper to assist in getting random values. For 32 Bit the getLong method is overriden by xpromaches code above. For 64 Bit it behaves as is.
2. The detection should be cross-platform (Windows is supported though it is not ported completely yet).
3. Every JNI method which sets jlong values must check if the value fits into size_t. If it overflows size_t a InvalidArgument Status object will be returned. If its ok a OK Status will be returned.
4. Setters which have this check will throw a RocksDBException if its no OK Status.
Additionally some other parts of code were corrected using the wrong type casts.
Test Plan:
make rocksdbjava
make jtest
Differential Revision: https://reviews.facebook.net/D24531
Extended Built-in comparators with ReverseBytewiseComparator.
Reverse key handling is under certain conditions essential. E.g. while
using timestamp versioned data.
As native-comparators were not available using JAVA-API. Both built-in comparators
were exposed via JNI to be set upon database creation time.
Summary: Fix JNI link error caused by the removal of options.db_stats_log_interval in https://reviews.facebook.net/D21915.
Test Plan:
make rocksdbjava
make jtest
Reviewers: ljin, ankgup87
Reviewed By: ankgup87
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D23505
Summary:
Fixed 32-bit overflowing issue when converting jlong to size_t by
capping jlong to std::numeric_limits<size_t>::max().
Test Plan:
make rocksdbjava
make jtest
Reviewers: ankgup87, ljin, sdong, igor
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D23511
Summary:
Include WriteBatch into RocksDBSample.java, fix how DbBenchmark.java handles WriteBatch.
Previously DbBenchmark.java does not use WriteBatch when benchmarks is set to fillbatch.
Test Plan:
make rocksdbjava -j32
make jtest
make jdb_bench
cd java
./jdb_bench.sh --benchmarks=fillbatch
Reviewers: naveenatceg, ljin, sdong, ankgup87
Reviewed By: ankgup87
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D22983
Summary: as title
Test Plan: make rocksdbjava
Reviewers: sdong, yhchiang, igor
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D23193
Summary:
Simply code by removing code path which does not use Arena
from NewInternalIterator
Test Plan:
make all check
make valgrind_check
Reviewers: sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D22395
Summary: as title
Test Plan:
tested on my mac
make rocksdbjava
make jtest
Reviewers: sdong, igor, yhchiang
Reviewed By: yhchiang
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D21963
Summary:
I will move compression related options in a separate diff since this
diff is already pretty lengthy.
I guess I will also need to change JNI accordingly :(
Test Plan: make all check
Reviewers: yhchiang, igor, sdong
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D21915
Summary:
1. Check status of CreateNewBackup. If status is not OK, then throw.
2. Add purgeOldBackups API
Test Plan:
make test
make sample
Reviewers: haobo, sdong, zzbennett, swapnilghike, yhchiang
Reviewed By: yhchiang
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D21753
Summary:
Update header inclusion as include/utilities/*.h has been moved to
include/rocksdb/utilities/*.h
Test Plan: make rocksdbjava
Reviewers: ljin, sdong, igor
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D20517
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:
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: 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
Summary:
Correct the library loading for zlib in RocksJava: zlib should
be loaded by loadLibrary("z") instead of loadLibrary("zlib").
Test Plan:
make rocksdbjava
cd java
make db_bench
./jdb_bench.sh --compression_type=zlib
Reviewers: sdong, ljin, ankgup87
Reviewed By: ankgup87
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19341
Summary:
Enable the random values in Java DB Bench to be generated based
on the compression_ratio specified in the command-line arguments.
Test Plan:
make rocksdbjava
java/jdb_bench.sh
Reviewers: sdong, ankgup87, haobo
Reviewed By: haobo
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19101
Summary:
Add HISTORY-JAVA.md and include both C++ and Java history files in .jar file
that describes important chagnes of RocksJava.
Test Plan: make rocksdbjava and make sure HISTORY.md is inside the .jar file
Reviewers: haobo, sdong, ankgup87
Reviewed By: ankgup87
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19185
Summary:
Improve the Java Doc of RocksObject, which explains more about the life-cycle
of a native handle.
Test Plan: no code change
Reviewers: haobo, sdong, ankgup87
Reviewed By: ankgup87
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19179
Summary:
Improve documentation for RocksEnv and its C++ resource. Specifically,
the result of RocksEnv::Default() is a singleton, and the ownership
of its c++ resource belongs to rocksdb c++. As a result, calling
dispose() of the return value of RocksDB::Default() will be no-op.
Test Plan: no code change.
Reviewers: haobo, ankgup87
Reviewed By: ankgup87
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18945
Summary:
1. Move disOwnNativeHandle() function from RocksDB to RocksObject
to allow other RocksObject to use disOwnNativeHandle() when its
ownership of native handle has been transferred.
2. RocksObject now has an abstract implementation of dispose(),
which does the following two things. First, it checks whether
both isOwningNativeHandle() and isInitialized() return true.
If so, it will call the protected abstract function dispose0(),
which all the subclasses of RocksObject should implement. Second,
it sets nativeHandle_ = 0. This redesign ensure all subclasses
of RocksObject have the same dispose behavior.
3. All subclasses of RocksObject now should implement dispose0()
instead of dispose(), and dispose0() will be called only when
isInitialized() returns true.
Test Plan:
make rocksdbjava
make jtest
Reviewers: dhruba, sdong, ankgup87, rsumbaly, swapnilghike, zzbennett, haobo
Reviewed By: haobo
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18801
Summary:
Originally, the boolean arguments in Java DB benchmark only takes
true and false as valid input. This diff allows boolean arguments
to be set using 0 or 1.
Test Plan:
make rocksdbjava
make jdb_bench
java/jdb_bench.sh --db=/tmp/path-not-exist --use_existing_db=1
java/jdb_bench.sh --db=/tmp/path-not-exist --use_existing_db=0
java/jdb_bench.sh --db=/tmp/path-not-exist --use_existing_db=1
Reviewers: haobo, dhruba, sdong, ankgup87, rsumbaly, swapnilghike, zzbennett
Reviewed By: haobo
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18687
Summary: Fixed a bug in Java DB Benchmark where random reads does not consider full key range.
Test Plan:
make rocksdbjava
make jdb_bench
cd java
jdb_bench.sh --db=/tmp/rocksdb-test --benchmarks=fillseq --use_existing_db=false --num=100000
jdb_bench.sh --db=/tmp/rocksdb-test --benchmarks=readrandom --use_existing_db=true --num=100000 --reads=1000000
Reviewers: haobo, sdong
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18693
Summary: Make read benchmarks print out found / not-found information.
Test Plan:
make rocksdbjava
make jdb_bench
cd java
./jdb_bench.sh
Reviewers: haobo, sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18699
Summary:
Before the Java binding for Env is ready, Java developers have no way to
control the number of background threads. This diff provides a temporary
solution where RocksDB.setMaxBackgroundCompactions() will affect the
number of background threads.
Note that once Env is ready. Changes made in this diff should be reverted.
Test Plan:
make rocksdbjava
make jtest
make jdb_bench
java/jdb_bench.sh
Reviewers: haobo, sdong
Reviewed By: sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18681
Summary:
Add RocksObject, the base class of all java objects which has a c++ pointer.
While the finalizer of a RocksObject will release its c++ resource, it is
suggested to call its RocksObject.dispose() to manually release its
c++ resource.
Existing RocksDB java classes are now extending RocksObject.
Test Plan:
make rocksdbjava
make jtest
make jdb_bench
Reviewers: haobo, dhruba, sdong, ankgup87, rsumbaly, swapnilghike, zzbennett
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18411
Summary:
* Add filluniquerandom
* Add readseq, implemented using iterator.
* Realize most command-line-arguments from db_bench.cc (70+).
* Some code are commented out as some of the options in Options
not yet have Java bindings.
* Add default option to DbBenchmark.
* RocksDB will now take the ownership of all c++ raw-pointers from Options, which includes a c++ raw-pointer for Filter.
Test Plan: ./jdb_bench.sh --db=/tmp/rocksjava-bench/db --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_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=134217728 --max_bytes_for_level_base=1073741824 --disable_wal=0 --wal_dir=/tmp/rocksjava-bench/wal --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=filluniquerandom,readseq,readrandom --use_existing_db=0 --threads=4
Reviewers: haobo, dhruba, sdong, ankgup87, rsumbaly, swapnilghike, zzbennett
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18267
Summary:
Add Java bindings and Java tests for 30+ rocksdb::Options. Codes are
machine-genearted based on include/rocksdb/options.h with manual-polishment.
Test Plan:
make rocksdbjava
make jtest
Reviewers: haobo, dhruba, sdong, ankgup87, rsumbaly, swapnilghike, zzbennett
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18273
Summary: Add Java binding and test for rocksdb::ReadOptions.
Test Plan:
make rocksdbjava
make jtest
Reviewers: haobo, dhruba, sdong, ankgup87, rsumbaly, swapnilghike, zzbennett
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18129
Summary:
Add Java bindings for memtables and sst format. Specifically,
add two abstract Java classses --- MemTableConfig and SstFormatConfig.
Each MemTable / SST implementation should has its own config class
extends MemTableConfig / SstFormatConfig respectively and pass it
to Options via setMemTableConfig / setSstConfig.
Test Plan:
make rocksdbjava
make jdb_test
make jdb_bench
java/jdb_bench.sh \
--benchmarks=fillseq,readrandom,readwhilewriting \
--memtablerep=hash_skiplist \
--use_plain_table=1 \
--key_size=20 \
--prefix_size=12 \
--value_size=100 \
--cache_size=17179869184 \
--disable_wal=0 \
--sync=0 \
Reviewers: haobo, ankgup87, sdong
Reviewed By: haobo
CC: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D17997
Summary:
Add a skeleton binding and test for BackupableDB which shows that BackupableDB
and RocksDB can share the same JNI calls.
Test Plan:
make rocksdbjava
make jtest
Reviewers: haobo, ankgup87, sdong, dhruba
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17793
Summary:
* Add a class SizeUnit to store frequently used consts. Currently
it has KB, MB, GB, TB, and PB.
* Change the parameter type of Options.writeBufferSize and Options.blockSize
from int to long.
Test Plan:
make rocksdbjava
make jtest
Reviewers: haobo, ankgup87, sdong, dhruba
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17703
Summary:
Add java bindings for Options.block_cache and allow DbBenchmark to
set cache_size.
Test Plan:
make rocksdbjava
make jtest
make jdb_Bench
Reviewers: haobo, sdong, ankgup87
Reviewed By: ankgup87
CC: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D17481
Summary:
Make each set function of Options / WriteOptions return its option instance.
Java developers can now easier specify each option like the following:
options.setCreateIfMissing(true)
.setWriteBufferSize(8 * 1024)
.setMaxWriteBufferNumber(3)
.setDisableSeekCompaction(true)
.setBlockSize(64 * 1024)
.setMaxBackgroundCompactions(10);
Test Plan:
make rocksdbjava
make jtest
Reviewers: haobo, ankgup87, sdong, dhruba
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17661
Summary:
* Add a benchmark for java binding for rocksdb. The java benchmark
is a complete rewrite based on the c++ db/db_bench.cc and the
DbBenchmark in dain's java leveldb.
* Support multithreading.
* 'readseq' is currently not supported as it requires RocksDB Iterator.
* usage:
--benchmarks
Comma-separated list of operations to run in the specified order
Actual benchmarks:
fillseq -- write N values in sequential key order in async mode
fillrandom -- write N values in random key order in async mode
fillbatch -- write N/1000 batch where each batch has 1000 values
in random key order in sync mode
fillsync -- write N/100 values in random key order in sync mode
fill100K -- write N/1000 100K values in random order in async mode
readseq -- read N times sequentially
readrandom -- read N times in random order
readhot -- read N times in random order from 1% section of DB
Meta Operations:
delete -- delete DB
DEFAULT: [fillseq, readrandom, fillrandom]
--compression_ratio
Arrange to generate values that shrink to this fraction of
their original size after compression
DEFAULT: 0.5
--use_existing_db
If true, do not destroy the existing database. If you set this
flag and also specify a benchmark that wants a fresh database, that benchmark will fail.
DEFAULT: false
--num
Number of key/values to place in database.
DEFAULT: 1000000
--threads
Number of concurrent threads to run.
DEFAULT: 1
--reads
Number of read operations to do. If negative, do --nums reads.
--key_size
The size of each key in bytes.
DEFAULT: 16
--value_size
The size of each value in bytes.
DEFAULT: 100
--write_buffer_size
Number of bytes to buffer in memtable before compacting
(initialized to default value by 'main'.)
DEFAULT: 4194304
--cache_size
Number of bytes to use as a cache of uncompressed data.
Negative means use default settings.
DEFAULT: -1
--seed
Seed base for random number generators.
DEFAULT: 0
--db
Use the db with the following name.
DEFAULT: /tmp/rocksdbjni-bench
* Add RocksDB.write().
Test Plan: make jbench
Reviewers: haobo, sdong, dhruba, ankgup87
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17433
Summary:
Fixed the following column family related compile error.
./java/rocksjni/write_batch.cc:211:66: error: cannot initialize a parameter of type 'rocksdb::ColumnFamilyMemTables *' with an lvalue of type 'rocksdb::MemTable *'
rocksdb::Status s = rocksdb::WriteBatchInternal::InsertInto(b, mem, &options);
^~~
Test Plan:
make jni
make jtest
Reviewers: igor, haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17577
Summary: Avoid a JNI call to GetByteArrayElements, which may introduce a byte-array-copy.
Test Plan: make jtest
Reviewers: haobo, sdong, dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17451
Summary:
Improve the internal interface between java and c++ for basic db operations
by including the RocksDB native handle (i.e., c++ pointer of rocksdb::DB)
as a input parameter of the internal interface.
This improvement reduces one JNI call per db operation from c++.
Test Plan: make test
Reviewers: haobo, sdong, dhruba
Reviewed By: sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17445
Summary:
* Add java api for rocksdb::WriteBatch and rocksdb::WriteOptions, which are necessary components
for running benchmark.
* Add java test for org.rocksdb.WriteBatch and org.rocksdb.WriteOptions.
* Add remove() to org.rocksdb.RocksDB, and add put() and remove() to RocksDB which take
org.rocksdb.WriteOptions.
Test Plan: make jtest
Reviewers: haobo, sdong, dhruba
Reviewed By: sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17373
Summary:
* [java] Add a java api for rocksdb::Options, currently only supports create_if_missing.
* [java] Add a test for RocksDBException in RocksDBSample.
Test Plan: make jtest
Reviewers: haobo, sdong
Reviewed By: haobo
CC: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D17385
Summary:
* [java] RocksDB now does not implement Closeable.
* [java] RocksDB.close() is now synchronized.
* [c++] Fix a bug in rocksjni.cc that does not release a java reference before
throwing an exception.
Test Plan:
make jni
make jtest
Reviewers: haobo, sdong
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17355
Summary: Fix a bug in RocksDBSample.java and minor code improvement in rocksjni.cc.
Test Plan:
make jni
make jtest
Reviewers: haobo, sdong
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17325
Summary:
This diff contains a simple jni library for rocksdb which supports open, get,
put and closeusing default options (including Options, ReadOptions, and
WriteOptions.) In the usual case, Java developers can use the c++ rocksdb
library in the way similar to the following:
RocksDB db = RocksDB.open(path_to_db);
...
db.put("hello".getBytes(), "world".getBytes();
byte[] value = db.get("hello".getBytes());
...
db.close();
Specifically, this diff has the following major classes:
* RocksDB: a Java wrapper class which forwards the operations
from the java side to c++ rocksdb library.
* RocksDBException: ncapsulates the error of an operation.
This exception type is used to describe an internal error from
the c++ rocksdb library.
This diff also include a simple java sample code calling c++ rocksdb library.
To build the rocksdb jni library, simply run make jni, and make jtest will try to
build and run the sample code.
Note that if the rocksdb is not built with the default glibc that Java uses,
java will try to load the wrong glibc during the run time. As a result,
the sample code might not work properly during the run time.
Test Plan:
* make jni
* make jtest
Reviewers: haobo, dhruba, sdong, igor, ljin
Reviewed By: dhruba
CC: leveldb, xjin
Differential Revision: https://reviews.facebook.net/D17109
Summary:
Change namespace from leveldb to rocksdb. This allows a single
application to link in open-source leveldb code as well as
rocksdb code into the same process.
Test Plan: compile rocksdb
Reviewers: emayanke
Reviewed By: emayanke
CC: leveldb
Differential Revision: https://reviews.facebook.net/D13287
Summary:
Debug and ported changes from the Open Source Github repo to our repo.
Wrote a script to easy build the java Library. future compiling java lib should just be running this script.
Test Plan: it compiles.
Reviewers: dhruba, leveldb
Reviewed By: dhruba
Differential Revision: https://reviews.facebook.net/D7323
Summary:
Porting various options, mostly related to Multi-threaded compaction to
Java.
Test Plan:
mvn test.
No clear plan on how else test.
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb, emayanke
Differential Revision: https://reviews.facebook.net/D7221
