Summary:
Before this PR, Iterator/InternalIterator may simultaneously have non-ok status() and Valid() = true. That state means that the last operation failed, but the iterator is nevertheless positioned on some unspecified record. Likely intended uses of that are:
* If some sst files are corrupted, a normal iterator can be used to read the data from files that are not corrupted.
* When using read_tier = kBlockCacheTier, read the data that's in block cache, skipping over the data that is not.
However, this behavior wasn't documented well (and until recently the wiki on github had misleading incorrect information). In the code there's a lot of confusion about the relationship between status() and Valid(), and about whether Seek()/SeekToLast()/etc reset the status or not. There were a number of bugs caused by this confusion, both inside rocksdb and in the code that uses rocksdb (including ours).
This PR changes the convention to:
* If status() is not ok, Valid() always returns false.
* Any seek operation resets status. (Before the PR, it depended on iterator type and on particular error.)
This does sacrifice the two use cases listed above, but siying said it's ok.
Overview of the changes:
* A commit that adds missing status checks in MergingIterator. This fixes a bug that actually affects us, and we need it fixed. `DBIteratorTest.NonBlockingIterationBugRepro` explains the scenario.
* Changes to lots of iterator types to make all of them conform to the new convention. Some bug fixes along the way. By far the biggest changes are in DBIter, which is a big messy piece of code; I tried to make it less big and messy but mostly failed.
* A stress-test for DBIter, to gain some confidence that I didn't break it. It does a few million random operations on the iterator, while occasionally modifying the underlying data (like ForwardIterator does) and occasionally returning non-ok status from internal iterator.
To find the iterator types that needed changes I searched for "public .*Iterator" in the code. Here's an overview of all 27 iterator types:
Iterators that didn't need changes:
* status() is always ok(), or Valid() is always false: MemTableIterator, ModelIter, TestIterator, KVIter (2 classes with this name anonymous namespaces), LoggingForwardVectorIterator, VectorIterator, MockTableIterator, EmptyIterator, EmptyInternalIterator.
* Thin wrappers that always pass through Valid() and status(): ArenaWrappedDBIter, TtlIterator, InternalIteratorFromIterator.
Iterators with changes (see inline comments for details):
* DBIter - an overhaul:
- It used to silently skip corrupted keys (`FindParseableKey()`), which seems dangerous. This PR makes it just stop immediately after encountering a corrupted key, just like it would for other kinds of corruption. Let me know if there was actually some deeper meaning in this behavior and I should put it back.
- It had a few code paths silently discarding subiterator's status. The stress test caught a few.
- The backwards iteration code path was expecting the internal iterator's set of keys to be immutable. It's probably always true in practice at the moment, since ForwardIterator doesn't support backwards iteration, but this PR fixes it anyway. See added DBIteratorTest.ReverseToForwardBug for an example.
- Some parts of backwards iteration code path even did things like `assert(iter_->Valid())` after a seek, which is never a safe assumption.
- It used to not reset status on seek for some types of errors.
- Some simplifications and better comments.
- Some things got more complicated from the added error handling. I'm open to ideas for how to make it nicer.
* MergingIterator - check status after every operation on every subiterator, and in some places assert that valid subiterators have ok status.
* ForwardIterator - changed to the new convention, also slightly simplified.
* ForwardLevelIterator - fixed some bugs and simplified.
* LevelIterator - simplified.
* TwoLevelIterator - changed to the new convention. Also fixed a bug that would make SeekForPrev() sometimes silently ignore errors from first_level_iter_.
* BlockBasedTableIterator - minor changes.
* BlockIter - replaced `SetStatus()` with `Invalidate()` to make sure non-ok BlockIter is always invalid.
* PlainTableIterator - some seeks used to not reset status.
* CuckooTableIterator - tiny code cleanup.
* ManagedIterator - fixed some bugs.
* BaseDeltaIterator - changed to the new convention and fixed a bug.
* BlobDBIterator - seeks used to not reset status.
* KeyConvertingIterator - some small change.
Closes https://github.com/facebook/rocksdb/pull/3810
Differential Revision: D7888019
Pulled By: al13n321
fbshipit-source-id: 4aaf6d3421c545d16722a815b2fa2e7912bc851d
Summary:
We were seeing the following error: "ThreadSanitizer: DenseSlabAllocator overflow. Dying."
It is fixable by mmap'ing a smaller region for keys' expected values, which this PR achieves by reducing the number of keys.
Closes https://github.com/facebook/rocksdb/pull/3803
Differential Revision: D7874478
Pulled By: ajkr
fbshipit-source-id: 433939f5cb92410ab4777d540cb0cc2ee0fe6c2e
Summary:
This PR comments out the rest of the unused arguments which allow us to turn on the -Wunused-parameter flag. This is the second part of a codemod relating to https://github.com/facebook/rocksdb/pull/3557.
Closes https://github.com/facebook/rocksdb/pull/3662
Differential Revision: D7426121
Pulled By: Dayvedde
fbshipit-source-id: 223994923b42bd4953eb016a0129e47560f7e352
Summary:
Possible interleaved execution of background compaction thread calling `FindObsoleteFiles (no full scan) / PurgeObsoleteFiles` and user thread calling `FindObsoleteFiles (full scan) / PurgeObsoleteFiles` can lead to race condition on which RocksDB attempts to delete a file twice. The second attempt will fail and return `IO error`. This may occur to other files, but this PR targets sst.
Also add a unit test to verify that this PR fixes the issue.
The newly added unit test `obsolete_files_test` has a test case for this scenario, implemented in `ObsoleteFilesTest#RaceForObsoleteFileDeletion`. `TestSyncPoint`s are used to coordinate the interleaving the `user_thread` and background compaction thread. They execute as follows
```
timeline user_thread background_compaction thread
t1 | FindObsoleteFiles(full_scan=false)
t2 | FindObsoleteFiles(full_scan=true)
t3 | PurgeObsoleteFiles
t4 | PurgeObsoleteFiles
V
```
When `user_thread` invokes `FindObsoleteFiles` with full scan, it collects ALL files in RocksDB directory, including the ones that background compaction thread have collected in its job context. Then `user_thread` will see an IO error when trying to delete these files in `PurgeObsoleteFiles` because background compaction thread has already deleted the file in `PurgeObsoleteFiles`.
To fix this, we make RocksDB remember which (SST) files have been found by threads after calling `FindObsoleteFiles` (see `DBImpl#files_grabbed_for_purge_`). Therefore, when another thread calls `FindObsoleteFiles` with full scan, it will not collect such files.
ajkr could you take a look and comment? Thanks!
Closes https://github.com/facebook/rocksdb/pull/3638
Differential Revision: D7384372
Pulled By: riversand963
fbshipit-source-id: 01489516d60012e722ee65a80e1449e589ce26d3
Summary:
I found that each instance of MySQLStyleTransactionTest.TransactionStressTest/x is taking more than 10 hours to complete on our continuous testing environment, causing the whole valgrind run to timeout after a day. So excluding these tests.
Closes https://github.com/facebook/rocksdb/pull/3652
Differential Revision: D7400332
Pulled By: sagar0
fbshipit-source-id: 987810574506d01487adf7c2de84d4817ec3d22d
Summary:
I modified the Makefile so that we can compile rocksdb on OpenBSD.
The instructions for building have been added to INSTALL.md.
The whole compilation process works fine like this on OpenBSD-current
Closes https://github.com/facebook/rocksdb/pull/3617
Differential Revision: D7323754
Pulled By: siying
fbshipit-source-id: 990037d1cc69138d22f85bd77ef4dc8c1ba9edea
Summary:
In original $ROCKSDB_HOME/Makefile, the command used to generate ctags is
```
ctags * -R
```
However, this failed to generate tags for me.
I did some search on the usage of ctags command and found that it should be
```
ctags -R .
```
or
```
ctags -R *
```
After the change, I can find the tags in vim using `:ts <identifier>`.
Closes https://github.com/facebook/rocksdb/pull/3626
Reviewed By: ajkr
Differential Revision: D7320217
Pulled By: riversand963
fbshipit-source-id: e4cd8f8a67842370a2343f0213df3cbd07754111
Summary:
https://blog.github.com/2018-02-23-weak-cryptographic-standards-removed/
Github dropped supporting some weak cryptographic protocols from their website couple of weeks ago which cause our vagrant build process to fail on curl downloading step. This diff force curl use tls v1.2 protocol if it is supported so that it does not rely on the default protocol on different systems.
Closes https://github.com/facebook/rocksdb/pull/3561
Differential Revision: D7148575
Pulled By: wpc
fbshipit-source-id: b8cecfdfeb2bc8236de2d0d14f044532befec98c
Summary:
Now we suppress alignment UBSAN error as a whole. Suppressing 3-way CRC and murmurhash feels a better idea than turning off alignment check as a whole.
Closes https://github.com/facebook/rocksdb/pull/3495
Differential Revision: D6971273
Pulled By: siying
fbshipit-source-id: 080b59fed6df494b9f622ef7cb5d42d39e6a8cdf
Summary:
…db_test
options_settable_test won't pass UBSAN so disable it.
blob_db_test fails in UBSAN as SnapshotList doesn't initialize all the fields in dummy snapshot. Fix it. I don't understand why only blob_db_test fails though.
Closes https://github.com/facebook/rocksdb/pull/3477
Differential Revision: D6928681
Pulled By: siying
fbshipit-source-id: e31dd300fcdecdfd4f6af279a0987fd0cdec5122
Summary:
Disable alignment check in UBSAN for now. Now we can't get signals to meaningful failures. We can reenable it after we figure out how we can suppress failures in finer grain manner.
Closes https://github.com/facebook/rocksdb/pull/3473
Differential Revision: D6925971
Pulled By: siying
fbshipit-source-id: a0f1a242cde866abbc5c1eeee9ff8d1d7d582ac4
Summary:
By default if ubsan detects any problem, it outputs a “runtime error:” message, and in most cases continues executing the program.
In order to make test abort on errors, option `-fno-sanitize-recover` is needed. [link](https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html)
Closes https://github.com/facebook/rocksdb/pull/3447
Differential Revision: D6854654
Pulled By: miasantreble
fbshipit-source-id: c48e892b0b38307029df38a67adda0e24257e481
Summary:
Java static builds are again broken, this time due Snappy version upgrade introduced in 90c1d81975 (#3331).
This is due to two reasons:
1. The new Snappy packages should now be downloaded from https://github.com/google/snappy/archive/<pkg.tar.gz> instead of https://github.com/google/snappy/releases/download/<pkg.tar.gz> which we are using now.
1. In addition to the the above URL change, Snappy changed its build from using autotools to CMake based : e69d9f8806/README.md (L65-L72)
So more changes are needed if we are going to upgrade to 1.1.7. Hence reverting the version upgrade until we figure them out.
Closes https://github.com/facebook/rocksdb/pull/3363
Differential Revision: D6716983
Pulled By: sagar0
fbshipit-source-id: f451a1bc5eb0bb090f4da07bc3e5ba72cf89aefa
Summary:
Java build on PPC64le has been broken since a few months, due to #2716. Fixing it with the least amount of changes.
(We should cleanup a little around this code when time permits).
This should fix the build failures seen in http://140.211.168.68:8080/job/Rocksdb/ .
Closes https://github.com/facebook/rocksdb/pull/3359
Differential Revision: D6712938
Pulled By: sagar0
fbshipit-source-id: 3046e8f072180693de2af4762934ec1ace309ca4
Summary:
With the ZSTD dictionary generator support added in #3057
`PORTABLE=1 ROCKSDB_NO_FBCODE=1 make rocksdbjavastatic` fails as it can't find zdict.h. Specifically due to:
e3a06f12d2/util/compression.h (L39)
In java static builds zstd code gets directly downloaded from https://github.com/facebook/zstd , and in there zdict.h is under dictBuilder directory. So, I modified libzstd.a target to use `make install` to collect all the header files into a single location and used that as the zstd's include path.
Closes https://github.com/facebook/rocksdb/pull/3260
Differential Revision: D6669850
Pulled By: sagar0
fbshipit-source-id: f8a7562a670e5aed4c4fb6034a921697590d7285
Summary:
added support for C and asm files as required for e612e31740.
Closes https://github.com/facebook/rocksdb/pull/3299
Differential Revision: D6612479
Pulled By: ajkr
fbshipit-source-id: 6263ed7c1602f249460421825c76b5721f396163
Summary:
**# Summary**
RocksDB uses SSE crc32 intrinsics to calculate the crc32 values but it does it in single way fashion (not pipelined on single CPU core). Intel's whitepaper () published an algorithm that uses 3-way pipelining for the crc32 intrinsics, then use pclmulqdq intrinsic to combine the values. Because pclmulqdq has overhead on its own, this algorithm will show perf gains on buffers larger than 216 bytes, which makes RocksDB a perfect user, since most of the buffers RocksDB call crc32c on is over 4KB. Initial db_bench show tremendous CPU gain.
This change uses the 3-way SSE algorithm by default. The old SSE algorithm is now behind a compiler tag NO_THREEWAY_CRC32C. If user compiles the code with NO_THREEWAY_CRC32C=1 then the old SSE Crc32c algorithm would be used. If the server does not have SSE4.2 at the run time the slow way (Non SSE) will be used.
**# Performance Test Results**
We ran the FillRandom and ReadRandom benchmarks in db_bench. ReadRandom is the point of interest here since it calculates the CRC32 for the in-mem buffers. We did 3 runs for each algorithm.
Before this change the CRC32 value computation takes about 11.5% of total CPU cost, and with the new 3-way algorithm it reduced to around 4.5%. The overall throughput also improved from 25.53MB/s to 27.63MB/s.
1) ReadRandom in db_bench overall metrics
PER RUN
Algorithm | run | micros/op | ops/sec |Throughput (MB/s)
3-way | 1 | 4.143 | 241387 | 26.7
3-way | 2 | 3.775 | 264872 | 29.3
3-way | 3 | 4.116 | 242929 | 26.9
FastCrc32c|1 | 4.037 | 247727 | 27.4
FastCrc32c|2 | 4.648 | 215166 | 23.8
FastCrc32c|3 | 4.352 | 229799 | 25.4
AVG
Algorithm | Average of micros/op | Average of ops/sec | Average of Throughput (MB/s)
3-way | 4.01 | 249,729 | 27.63
FastCrc32c | 4.35 | 230,897 | 25.53
2) Crc32c computation CPU cost (inclusive samples percentage)
PER RUN
Implementation | run | TotalSamples | Crc32c percentage
3-way | 1 | 4,572,250,000 | 4.37%
3-way | 2 | 3,779,250,000 | 4.62%
3-way | 3 | 4,129,500,000 | 4.48%
FastCrc32c | 1 | 4,663,500,000 | 11.24%
FastCrc32c | 2 | 4,047,500,000 | 12.34%
FastCrc32c | 3 | 4,366,750,000 | 11.68%
**# Test Plan**
make -j64 corruption_test && ./corruption_test
By default it uses 3-way SSE algorithm
NO_THREEWAY_CRC32C=1 make -j64 corruption_test && ./corruption_test
make clean && DEBUG_LEVEL=0 make -j64 db_bench
make clean && DEBUG_LEVEL=0 NO_THREEWAY_CRC32C=1 make -j64 db_bench
Closes https://github.com/facebook/rocksdb/pull/3173
Differential Revision: D6330882
Pulled By: yingsu00
fbshipit-source-id: 8ec3d89719533b63b536a736663ca6f0dd4482e9
Summary:
The TSAN version of tests could take quite long. Make the buck tests parallel to avoid timeouts.
Closes https://github.com/facebook/rocksdb/pull/3280
Differential Revision: D6581594
Pulled By: maysamyabandeh
fbshipit-source-id: 3f8476d8c69f0183e394fa8a2089dd8d4e90c90c
Summary:
Add ROCKSDB_VALGRIND_RUN macro and suppress false-positive "unimplemented functionality" throw by valgrind for steam hints.
Another approach would be add a valgrind suppress file. Valgrind is suppose to print the suppression when given "--gen-suppressions=all" param, which is suppose to be the content for the suppression file. But it doesn't print.
Closes https://github.com/facebook/rocksdb/pull/3174
Differential Revision: D6338786
Pulled By: yiwu-arbug
fbshipit-source-id: 3559efa5f3b92d40d09ad6ac82bc7b59f86c75aa
Summary:
The current implementation of PinnableSlice move assignment have an issue #3163. We are moving away from it instead of try to get the move assignment right, since it is too tricky.
Closes https://github.com/facebook/rocksdb/pull/3164
Differential Revision: D6319201
Pulled By: yiwu-arbug
fbshipit-source-id: 8f3279021f3710da4a4caa14fd238ed2df902c48
Summary:
Dynamic adjustment of rate limit according to demand for background I/O. It increases by a factor when limiter is drained too frequently, and decreases by the same factor when limiter is not drained frequently enough. The parameters for this behavior are fixed in `GenericRateLimiter::Tune`. Other changes:
- make rate limiter's `Env*` configurable for testing
- track num drain intervals in RateLimiter so we don't have to rely on stats, which may be shared across different DB instances from the ones that share the RateLimiter.
Closes https://github.com/facebook/rocksdb/pull/2899
Differential Revision: D5858704
Pulled By: ajkr
fbshipit-source-id: cc2bac30f85e7f6fd63655d0a6732ef9ed7403b1
Summary:
Make SnapshotConcurrentAccessTest run in the beginning of the queue.
Test Plan
`make all check -j64` on devserver
Closes https://github.com/facebook/rocksdb/pull/2962
Differential Revision: D5965871
Pulled By: yiwu-arbug
fbshipit-source-id: 8cb5a47c2468be0fbbb929226a143ec5848bfaa9
Summary:
Add kTypeBlobIndex value type, which will be used by blob db only, to insert a (key, blob_offset) KV pair. The purpose is to
1. Make it possible to open existing rocksdb instance as blob db. Existing value will be of kTypeIndex type, while value inserted by blob db will be of kTypeBlobIndex.
2. Make rocksdb able to detect if the db contains value written by blob db, if so return error.
3. Make it possible to have blob db optionally store value in SST file (with kTypeValue type) or as a blob value (with kTypeBlobIndex type).
The root db (DBImpl) basically pretended kTypeBlobIndex are normal value on write. On Get if is_blob is provided, return whether the value read is of kTypeBlobIndex type, or return Status::NotSupported() status if is_blob is not provided. On scan allow_blob flag is pass and if the flag is true, return wether the value is of kTypeBlobIndex type via iter->IsBlob().
Changes on blob db side will be in a separate patch.
Closes https://github.com/facebook/rocksdb/pull/2886
Differential Revision: D5838431
Pulled By: yiwu-arbug
fbshipit-source-id: 3c5306c62bc13bb11abc03422ec5cbcea1203cca
Summary:
This enables us to crossbuild pcc64le RocksJava binaries with a suitably old version of glibc (2.17) on CentOS 7.
Closes https://github.com/facebook/rocksdb/pull/2491
Differential Revision: D5955301
Pulled By: sagar0
fbshipit-source-id: 69ef9746f1dc30ffde4063dc764583d8c7ae937e
Summary:
TSAN shows error when we grab too many locks at the same time. In TSAN crash test, make one shard key cover 2^22 keys so that no many keys will be hold at the same time.
Closes https://github.com/facebook/rocksdb/pull/2719
Differential Revision: D5609035
Pulled By: siying
fbshipit-source-id: 930e5d63fff92dbc193dc154c4c615efbdf06c6a
Summary:
Commit 4f81ab38bf has the test wrong.
clang doesn't support a -dumpversion option. By lucky coincidence
clang/gcc --version both place a version number at the same output location
when --verison is passed.
Example output (1st line only).
$ clang --version
clang version 3.9.1 (tags/RELEASE_391/final)
$ gcc --version
gcc (GCC) 6.4.1 20170727 (Red Hat 6.4.1-1)
During the test of the compiler we ensure that a minimum version is met
as Makefile doesn't support patterns.
Also xcode9 doesn't seem affected by https://github.com/facebook/rocksdb/issues/2672
and also doesn't have "clang" as the first part of its output so the
fix implemented here also is Apple clang friendly.
$ clang --version
Apple LLVM version 9.0.0 (clang-900.0.31)
Signed-off-by: Daniel Black <daniel.black@au.ibm.com>
Closes https://github.com/facebook/rocksdb/pull/2699
Differential Revision: D5600818
Pulled By: yiwu-arbug
fbshipit-source-id: 3b0f2751becb53c1c35468bf29f3f828e7cf2c2a
Summary:
Replace dynamic_cast<> so that users can choose to build with RTTI off, so that they can save several bytes per object, and get tiny more memory available.
Some nontrivial changes:
1. Add Comparator::GetRootComparator() to get around the internal comparator hack
2. Add the two experiemental functions to DB
3. Add TableFactory::GetOptionString() to avoid unnecessary casting to get the option string
4. Since 3 is done, move the parsing option functions for table factory to table factory files too, to be symmetric.
Closes https://github.com/facebook/rocksdb/pull/2645
Differential Revision: D5502723
Pulled By: siying
fbshipit-source-id: fd13cec5601cf68a554d87bfcf056f2ffa5fbf7c
Summary:
platform_dependent tests in Travis now builds all tests, which is not needed. Only build those tests we need to run.
Closes https://github.com/facebook/rocksdb/pull/2647
Differential Revision: D5513954
Pulled By: siying
fbshipit-source-id: 4d540b146124e70dd25586c47939d19f93655b0a
Summary:
Major changes in this PR:
* Implement CassandraCompactionFilter to remove expired columns and rows (if all column expired)
* Move cassandra related code from utilities/merge_operators/cassandra to utilities/cassandra/*
* Switch to use shared_ptr<> from uniqu_ptr for Column membership management in RowValue. Since columns do have multiple owners in Merge and GC process, use shared_ptr helps make RowValue immutable.
* Rename cassandra_merge_test to cassandra_functional_test and add two TTL compaction related tests there.
Closes https://github.com/facebook/rocksdb/pull/2588
Differential Revision: D5430010
Pulled By: wpc
fbshipit-source-id: 9566c21e06de17491d486a68c70f52d501f27687
Summary:
Instead of ignoring UBSan checks, fix the negative shifts in
Hash(). Also add test to make sure the hash values are stable over
time. The values were computed before this change, so the test also
verifies the correctness of the change.
Closes https://github.com/facebook/rocksdb/pull/2546
Differential Revision: D5386369
Pulled By: yiwu-arbug
fbshipit-source-id: 6de4b44461a544d6222cc5d72d8cda2c0373d17e
Summary:
1. The buckifier script assume each test "foo" comes with a .cc file of the same name (i.e. foo.cc). Update cassandra tests to follow this pattern so that the buckifier script can recognize them.
2. add blob_db_test
Closes https://github.com/facebook/rocksdb/pull/2506
Differential Revision: D5331517
Pulled By: yiwu-arbug
fbshipit-source-id: 86f3eba471fc621186ab44cbd073b6162cde8e57
Summary:
This PR adds support for encrypting data stored by RocksDB when written to disk.
It adds an `EncryptedEnv` override of the `Env` class with matching overrides for sequential&random access files.
The encryption itself is done through a configurable `EncryptionProvider`. This class creates is asked to create `BlockAccessCipherStream` for a file. This is where the actual encryption/decryption is being done.
Currently there is a Counter mode implementation of `BlockAccessCipherStream` with a `ROT13` block cipher (NOTE the `ROT13` is for demo purposes only!!).
The Counter operation mode uses an initial counter & random initialization vector (IV).
Both are created randomly for each file and stored in a 4K (default size) block that is prefixed to that file. The `EncryptedEnv` implementation is such that clients of the `Env` class do not see this prefix (nor data, nor in filesize).
The largest part of the prefix block is also encrypted, and there is room left for implementation specific settings/values/keys in there.
To test the encryption, the `DBTestBase` class has been extended to consider a new environment variable called `ENCRYPTED_ENV`. If set, the test will setup a encrypted instance of the `Env` class to use for all tests.
Typically you would run it like this:
```
ENCRYPTED_ENV=1 make check_some
```
There is also an added test that checks that some data inserted into the database is or is not "visible" on disk. With `ENCRYPTED_ENV` active it must not find plain text strings, with `ENCRYPTED_ENV` unset, it must find the plain text strings.
Closes https://github.com/facebook/rocksdb/pull/2424
Differential Revision: D5322178
Pulled By: sdwilsh
fbshipit-source-id: 253b0a9c2c498cc98f580df7f2623cbf7678a27f
Summary:
Improve write buffer manager in several ways:
1. Size is tracked when arena block is allocated, rather than every allocation, so that it can better track actual memory usage and the tracking overhead is slightly lower.
2. We start to trigger memtable flush when 7/8 of the memory cap hits, instead of 100%, and make 100% much harder to hit.
3. Allow a cache object to be passed into buffer manager and the size allocated by memtable can be costed there. This can help users have one single memory cap across block cache and memtable.
Closes https://github.com/facebook/rocksdb/pull/2350
Differential Revision: D5110648
Pulled By: siying
fbshipit-source-id: b4238113094bf22574001e446b5d88523ba00017
Mike Kolupaev