Commit Graph

689 Commits

Author SHA1 Message Date
agiardullo 8019aa9b55 improve test for manifest write failure
Summary: Improve testing per discussion in D52989

Test Plan: ran test

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D53211
2016-01-22 11:47:59 -08:00
Andrew Kryczka eceb5cb1b7 Split db_test.cc (part 1: properties)
Summary:
Moved all the tests that verify property correctness into a separate
file. The goal is to reduce compile time and complexity of db_test. I didn't
add parallelism for db_properties_test, even though these tests were
parallelized in db_test, since the file is small enough that it won't matter.

Some of these moves may be controversial since it's hard to say whether the
test is "verifying property correctness," or "using properties to verify
rocksdb's correctness." I'm interested in any opinions.

Test Plan: ran db_properties_test, also waiting on "make commit-prereq -j32"

Reviewers: yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D52995
2016-01-20 15:17:52 -08:00
David Bernard 3f12e16f27 Make alloca.h optional 2016-01-19 06:17:31 +00:00
David Bernard d78c6b28c4 Changes for build on solaris
Makefile adjust paths for solaris build
Makefile enable _GLIBCXX_USE_C99 so that std::to_string is available
db_compaction_test.cc Initialise a variable to avoid a compilation error
db_impl.cc Include <alloca.h>
db_test.cc Include <alloca.h>
Environment.java recognise solaris envrionment
options_bulder.cc Make log unambiguous
geodb_impl.cc Make log and floor unambiguous
2016-01-19 04:45:21 +00:00
agiardullo a2422f0533 fix potential test SleepingTask race condition
Summary: Make sure SleepingTask has bene run before it goes out of scope.

Test Plan: run test

Reviewers: kradhakrishnan

Reviewed By: kradhakrishnan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D52581
2016-01-06 11:51:09 -08:00
Nathan Bronson ac16663bd6 use -Werror=missing-field-initializers, to closer match MyRocks build
Summary:
myrocks seems to build rocksdb using
-Wmissing-field-initializers (and treats warnings as errors).  This diff
adds that flag to the rocksdb build, and fixes the compilation failures
that result.  I have not checked for any other differences in the build
flags for rocksdb build as part of myrocks.

Test Plan: make check

Reviewers: sdong, rven

Reviewed By: rven

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D52443
2015-12-30 14:56:18 -08:00
Siying Dong 22c0ed8a5f Disable Visual Studio Warning C4351
Currently Windows build is broken because of Warning C4351. Disable the warning before figuring out the right way to fix it.
2015-12-28 15:06:34 -08:00
sdong 5b2587b5cb DBTest.HardLimit use special memtable
Summary: DBTest.HardLimit fails in appveyor build. Use special mem table to make the test behavior depends less on platform

Test Plan: Run the test with JEMALLOC both on and off.

Reviewers: yhchiang, kradhakrishnan, rven, anthony, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52317
2015-12-25 10:25:34 -08:00
Siying Dong 298ba27ae2 Merge pull request #846 from yuslepukhin/enble_c4244_lossofdata
Enable MS compiler warning c4244.
2015-12-23 22:59:42 -08:00
sdong d43da8ae0d DBTest.DelayedWriteRate: fix assert of sign and unsign comparison
Summary: DBTest.DelayedWriteRate has sign and unsign comparisons that break Windows build. Fix it.

Test Plan: Build and run the test modified.

Reviewers: IslamAbdelRahman, rven, anthony, yhchiang, kradhakrishnan

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52311
2015-12-23 22:38:12 -08:00
sdong b9f77ba12b When slowdown is triggered, reduce the write rate
Summary: It's usually hard for users to set a value of options.delayed_write_rate. With this diff, after slowdown condition triggers, we greedily reduce write rate if estimated pending compaction bytes increase. If estimated compaction pending bytes drop, we increase the write rate.

Test Plan:
Add a unit test
Test with db_bench setting:
TEST_TMPDIR=/dev/shm/ ./db_bench --benchmarks=fillrandom -num=10000000 --soft_pending_compaction_bytes_limit=1000000000 --hard_pending_compaction_bytes_limit=3000000000 --delayed_write_rate=100000000

and make sure without the commit, write stop will happen, but with the commit, it will not happen.

Reviewers: igor, anthony, rven, yhchiang, kradhakrishnan, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52131
2015-12-23 11:33:15 -08:00
Andrew Kryczka 445d5b8c5c Fix clang build
Summary:
Missed this in https://reviews.facebook.net/D51633 because I didn't
wait for 'make commit-prereq' to finish

Test Plan: make clean && USE_CLANG=1 make -j32 all

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D52275
2015-12-23 10:49:42 -08:00
Andrew Kryczka e089db40f9 Skip bottom-level filter block caching when hit-optimized
Summary:
When Get() or NewIterator() trigger file loads, skip caching the filter block if
(1) optimize_filters_for_hits is set and (2) the file is on the bottommost
level. Also skip checking filters under the same conditions, which means that
for a preloaded file or a file that was trivially-moved to the bottom level, its
filter block will eventually expire from the cache.

- added parameters/instance variables in various places in order to propagate the config ("skip_filters") from version_set to block_based_table_reader
- in BlockBasedTable::Rep, this optimization prevents filter from being loaded when the file is opened simply by setting filter_policy = nullptr
- in BlockBasedTable::Get/BlockBasedTable::NewIterator, this optimization prevents filter from being used (even if it was loaded already) by setting filter = nullptr

Test Plan:
updated unit test:

  $ ./db_test --gtest_filter=DBTest.OptimizeFiltersForHits

will also run 'make check'

Reviewers: sdong, igor, paultuckfield, anthony, rven, kradhakrishnan, IslamAbdelRahman, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D51633
2015-12-23 10:15:07 -08:00
Zhipeng Jia aa515823bc Fix clang warning 2015-12-23 19:23:58 +08:00
sdong d72b31774e Slowdown when writing to the last write buffer
Summary: Now if inserting to mem table is much faster than writing to files, there is no mechanism users can rely on to avoid stopping for reaching options.max_write_buffer_number. With the commit, if there are more than four maximum write buffers configured, we slow down to the rate of options.delayed_write_rate while we reach the last one.

Test Plan:
1. Add a new unit test.
2. Run db_bench with

./db_bench --benchmarks=fillrandom --num=10000000 --max_background_flushes=6 --batch_size=32 -max_write_buffer_number=4 --delayed_write_rate=500000 --statistics

based on hard drive and see stopping is avoided with the commit.

Reviewers: yhchiang, IslamAbdelRahman, anthony, rven, kradhakrishnan, igor

Reviewed By: igor

Subscribers: MarkCallaghan, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52047
2015-12-17 10:49:08 -08:00
Islam AbdelRahman aececc209e Introduce ReadOptions::pin_data (support zero copy for keys)
Summary:
This patch update the Iterator API to introduce new functions that allow users to keep the Slices returned by key() valid as long as the Iterator is not deleted

ReadOptions::pin_data : If true keep loaded blocks in memory as long as the iterator is not deleted
Iterator::IsKeyPinned() : If true, this mean that the Slice returned by key() is valid as long as the iterator is not deleted

Also add a new option BlockBasedTableOptions::use_delta_encoding to allow users to disable delta_encoding if needed.

Benchmark results (using https://phabricator.fb.com/P20083553)

```
// $ du -h /home/tec/local/normal.4K.Snappy/db10077
// 6.1G    /home/tec/local/normal.4K.Snappy/db10077

// $ du -h /home/tec/local/zero.8K.LZ4/db10077
// 6.4G    /home/tec/local/zero.8K.LZ4/db10077

// Benchmarks for shard db10077
// _build/opt/rocks/benchmark/rocks_copy_benchmark \
//      --normal_db_path="/home/tec/local/normal.4K.Snappy/db10077" \
//      --zero_db_path="/home/tec/local/zero.8K.LZ4/db10077"

// First run
// ============================================================================
// rocks/benchmark/RocksCopyBenchmark.cpp          relative  time/iter  iters/s
// ============================================================================
// BM_StringCopy                                                 1.73s  576.97m
// BM_StringPiece                                   103.74%      1.67s  598.55m
// ============================================================================
// Match rate : 1000000 / 1000000

// Second run
// ============================================================================
// rocks/benchmark/RocksCopyBenchmark.cpp          relative  time/iter  iters/s
// ============================================================================
// BM_StringCopy                                              611.99ms     1.63
// BM_StringPiece                                   203.76%   300.35ms     3.33
// ============================================================================
// Match rate : 1000000 / 1000000
```

Test Plan: Unit tests

Reviewers: sdong, igor, anthony, yhchiang, rven

Reviewed By: rven

Subscribers: dhruba, lovro, adsharma

Differential Revision: https://reviews.facebook.net/D48999
2015-12-16 12:08:30 -08:00
Gunnar Kudrjavets 97265f5f14 Fix minor bugs in delete operator, snprintf, and size_t usage
Summary:
List of changes:

1) Fix the snprintf() usage in cases where wrong variable was used to determine the output buffer size.

2) Remove unnecessary checks before calling delete operator.

3) Increase code correctness by using size_t type when getting vector's size.

4) Unify the coding style by removing namespace::std usage at the top of the file to confirm to the majority usage.

5) Fix various lint errors pointed out by 'arc lint'.

Test Plan:
Code review and build:

git diff
make clean
make -j 32 commit-prereq
arc lint

Reviewers: kradhakrishnan, sdong, rven, anthony, yhchiang, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51849
2015-12-15 15:26:20 -08:00
Venkatesh Radhakrishnan 030215bf01 Running manual compactions in parallel with other automatic or manual compactions in restricted cases
Summary:
This diff provides a framework for doing manual
compactions in parallel with other compactions. We now have a deque of manual compactions. We also pass manual compactions as an argument from RunManualCompactions down to
BackgroundCompactions, so that RunManualCompactions can be reentrant.
Parallelism is controlled by the two routines
ConflictingManualCompaction to allow/disallow new parallel/manual
compactions based on already existing ManualCompactions. In this diff, by default manual compactions still have to run exclusive of other compactions. However, by setting the compaction option, exclusive_manual_compaction to false, it is possible to run other compactions in parallel with a manual compaction. However, we are still restricted to one manual compaction per column family at a time. All of these restrictions will be relaxed in future diffs.
I will be adding more tests later.

Test Plan: Rocksdb regression + new tests + valgrind

Reviewers: igor, anthony, IslamAbdelRahman, kradhakrishnan, yhchiang, sdong

Reviewed By: sdong

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47973
2015-12-14 11:20:34 -08:00
Dmitri Smirnov a6fbdd64e0 Fix rebase issues and new code warnings. 2015-12-11 16:56:24 -08:00
Dmitri Smirnov 236fe21c92 Enable MS compiler warning c4244.
Mostly due to the fact that there are differences in sizes of int,long
  on 64 bit systems vs GNU.
2015-12-11 16:47:34 -08:00
charsyam c30b499541 fix typos in comments 2015-12-11 01:54:48 +09:00
sdong 56e77f0967 Deprecate options.soft_rate_limit and add options.soft_pending_compaction_bytes_limit
Summary: Deprecate options.soft_rate_limit, which is hard to tune, with options.soft_pending_compaction_bytes_limit, which would trigger the slowdown if estimated pending compaction bytes exceeds the threshold. The hope is to make it more striaght-forward to tune.

Test Plan: Modify DBTest.SoftLimit to cover options.soft_pending_compaction_bytes_limit instead; run all unit tests.

Reviewers: IslamAbdelRahman, yhchiang, rven, kradhakrishnan, igor, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51117
2015-12-09 18:22:45 -08:00
Siying Dong fa3dbf203f Merge pull request #853 from Vaisman/enable_C4267_warning
Enable C4267 warning
2015-12-08 17:59:24 -08:00
sdong 770dea9325 Fix occasional failure of DBTest.DynamicCompactionOptions
Summary: DBTest.DynamicCompactionOptions ocasionally fails during valgrind run. We sent a sleeping task to block compaction thread pool but we don't wait it to run.

Test Plan: Run the test multiple times in an environment which can cause failure.

Reviewers: rven, kradhakrishnan, igor, IslamAbdelRahman, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51687
2015-12-07 18:38:39 -08:00
Alex Yang e8180f9901 added public api to schedule flush/compaction, code to prevent race with db::open
Summary:
Fixes T8781168.

Added a new function EnableAutoCompactions in db.h to be publicly
avialable.  This allows compaction to be re-enabled after disabling it via
SetOptions

Refactored code to set the dbptr earlier on in TransactionDB::Open and DB::Open
Temporarily disable auto_compaction in TransactionDB::Open until dbptr is set to
prevent race condition.

Test Plan:
Ran make all check

verified fix on myrocks side:
was able to reproduce the seg fault with
../tools/mysqltest.sh --mem --force rocksdb.drop_table

method was to manually sleep the thread after DB::Open but before TransactionDB ptr was
assigned in transaction_db_impl.cc:
  DB::Open(db_options, dbname, column_families_copy, handles, &db);
  clock_t goal = (60000 * 10) + clock();
  while (goal > clock());
  ...dbptr(aka rdb) gets assigned below

verified my changes fixed the issue.

Also added unit test 'ToggleAutoCompaction' in transaction_test.cc

Reviewers: hermanlee4, anthony

Reviewed By: anthony

Subscribers: alex, dhruba

Differential Revision: https://reviews.facebook.net/D51147
2015-12-03 22:59:44 -08:00
sdong bcd7bd1229 Relax verification condition of DBTest.SuggestCompactRangeTest
Summary: Verifiction condition of DBTest.SuggestCompactRangeTest is too strict. Based on key distribution, we might have more small files in last level. Not check number of files in the last level.

Test Plan: Run DBTest.SuggestCompactRangeTest with both of jemalloc on and off.

Reviewers: rven, IslamAbdelRahman, yhchiang, kradhakrishnan, igor, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51501
2015-12-01 21:12:24 -08:00
sdong f9103d9a30 DBTest.DynamicCompactionOptions: More deterministic and readable
Summary: DBTest.DynamicCompactionOptions sometimes fails the assert but I can't repro it locally. Make it more deterministic and readable and see whether the problem is still there.

Test Plan: Run tht test and make sure it passes

Reviewers: kradhakrishnan, yhchiang, igor, rven, IslamAbdelRahman, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51309
2015-12-01 16:49:47 -08:00
sdong ef8ed3681c Fix DBTest.SuggestCompactRangeTest for disable jemalloc case
Summary: DBTest.SuggestCompactRangeTest fails for the case when jemalloc is disabled, including ASAN and valgrind builds. It is caused by the improvement of skip list, which allocates different size of nodes for a new records. Fix it by using a special mem table that triggers a flush by number of entries. In that way the behavior will be consistent for all allocators.

Test Plan: Run the test with both of DISABLE_JEMALLOC=1 and 0

Reviewers: anthony, rven, yhchiang, kradhakrishnan, igor, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51423
2015-11-30 16:40:47 -08:00
sdong db320b1b82 DB to only flush the column family with the largest memtable while option.db_write_buffer_size is hit
Summary: When option.db_write_buffer_size is hit, we currently flush all column families. Move to flush the column family with the largest active memt table instead. In this way, we can avoid too many small files in some cases.

Test Plan: Modify test DBTest.SharedWriteBuffer to work with the updated behavior

Reviewers: kradhakrishnan, yhchiang, rven, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: march, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51291
2015-11-30 13:36:57 -08:00
sdong 33e0c93826 Reduce extra key comparision in DBIter::Next()
Summary: Now DBIter::Next() always compares with current key with itself first, which is unnecessary if the last key is not a merge key. I made the change and didn't see db_iter_test fails. Want to hear whether people have any idea what I miss.

Test Plan: Run all unit tests

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48279
2015-11-24 17:16:18 -08:00
Nathan Bronson 9a9d4759b2 InlineSkipList part 3/3 - new skiplist type that colocates key and node
Summary:
This diff completes the creation of InlineSkipList<Cmp>, which is like
SkipList<const char*, Cmp> but it always allocates the key contiguously
with the node.  This allows us to remove the pointer from the node
to the key.  As a result the memory usage of the skip list is reduced
(by 1 to sizeof(void*) bytes depending on the padding required to align
the key storage), cache locality is improved, and we halve the number
of calls to the allocator.

For skip lists whose keys are freshly-allocated const char*,
InlineSkipList is stricly preferrable to SkipList.  This diff doesn't
replace SkipList, however, because some of the use cases of SkipList in
RocksDB are either character sequences that are not allocated at the
same time as the skip list node allocation (for example
hash_linklist_rep) or have different key types (for example
write_batch_with_index).  Taking advantage of inline allocation for
those cases is left to future work.

The perf win is biggest for small values.  For single-threaded CPU-bound
(32M fillrandom operations with no WAL log) with 16 byte keys and 0 byte
values, the db_bench perf goes from ~310k ops/sec to ~410k ops/sec.  For
large values the improvement is less pronounced, but seems to be between
5% and 10% on the same configuration.

Test Plan: make check

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D51123
2015-11-24 15:16:02 -08:00
Vasili Svirski 41b32c6059 Enable C4267 warning
* conversion from 'size_t' to 'type', by add static_cast

Tested:
* by build solution on Windows, Linux locally,
* run tests
* build CI system successful
2015-11-24 16:33:09 +03:00
agiardullo c5b467306d Fix race condition that causes valgrind failures
Summary: DBTest.DynamicLevelCompressionPerLevel2 sometimes fails during valgrind runs.  This causes our valgrind tests to fail.  Not sure what the best fix is for this test, but hopefully this simple change is sufficient.

Test Plan: run test

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51111
2015-11-20 18:26:48 -08:00
yuslepukhin 047bd22aae Build on Visual Studio 2015 Update 1 2015-11-20 15:31:47 -08:00
sdong d5540e18e6 DBTest.MergeTestTime to only use fake time to be determinstic
Summary: DBTest.MergeTestTime is a test verifying timing counters. Depending on real time may cause non-determinstic results. Change to fake time to be determinsitic.

Test Plan: Run the test and make sure it passes

Reviewers: yhchiang, anthony, rven, kradhakrishnan, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D50883
2015-11-17 14:40:23 -08:00
sdong 5cbb7e43e0 DBTest.MergeTestTime: relax counter upper bound verification
Summary: Timing counters' upper bounds depend on platform. It frequently fails in valgrind runs. Relax the upper bound.

Test Plan: Run the same valgrind test and make sure it passes.

Reviewers: rven, anthony, kradhakrishnan, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D50829
2015-11-16 19:47:07 -08:00
Yueh-Hsuan Chiang 3ecbab0040 Add GetAggregatedIntProperty(): returns the aggregated value from all CFs
Summary:
This patch adds GetAggregatedIntProperty() that returns the aggregated
value from all CFs

Test Plan: Added a test in db_test

Reviewers: igor, sdong, anthony, IslamAbdelRahman, rven

Reviewed By: rven

Subscribers: rven, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D49497
2015-11-03 15:54:18 -08:00
Dmitri Smirnov eaaf081d16 Do not suppress C4018 'expression' : signed/unsigned mismatch
The code compiles cleanly for the most part. Fix db_test.
  Move debug file to testutil library.
2015-10-30 17:03:16 -07:00
Islam AbdelRahman ff4499e297 Update DB::AddFile() to have less restrictions
Summary:
Update DB::AddFile() restrictions to be
  - Key range in loaded table file don't overlap with existing keys or tombstones in DB.
  - No other writes happen during AddFile call.

The updated AddFile() will verify that the file key range don't overlap with any keys or tombstones in the DB, and then add the file to L0

Test Plan: unit tests

Reviewers: igor, rven, anthony, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: adsharma, ameyag, dhruba

Differential Revision: https://reviews.facebook.net/D49233
2015-10-30 16:38:10 -07:00
sdong 296c3a1f94 "make format" in some recent commits
Summary: Run "make format" for some recent commits.

Test Plan: Build and run tests

Reviewers: IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D49707
2015-10-29 17:11:14 -07:00
Praveen Rao 4ce117c4d5 Merge branch 'master' into wal_filter 2015-10-26 19:03:34 -07:00
Praveen Rao 32cdec634e Fail recovery if filter provides more records than original and corresponding unit-test, fix naming conventions 2015-10-26 18:11:18 -07:00
Siying Dong 138876a62c Merge pull request #746 from ceph/wip-recycle
Add Options.recycle_log_file_num for Recycling WAL Files
2015-10-26 15:01:28 -07:00
Dmitri Smirnov 3c750b59ae No need to #ifdef test only code on windows 2015-10-22 15:15:37 -07:00
Praveen Rao 7951b9b079 make field order match initialization order 2015-10-19 17:03:01 -07:00
Praveen Rao 2938c5c137 merge upstream changes 2015-10-19 15:21:33 -07:00
Praveen Rao 0c59691dde Handle multiple batches in single log record - allow app to return a new batch + allow app to return corrupted record status 2015-10-19 13:27:40 -07:00
Alexey Maykov f18acd8875 Fixed the clang compilation failure
Summary: As above.

Test Plan: USE_CLANG=1 make check -j

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48981
2015-10-19 10:38:50 -07:00
Sage Weil 5830c699f2 log_writer: pass log number and whether recycling is enabled to ctor
When we recycle log files, we need to mix the log number into the CRC
for each record.  Note that for logs that don't get recycled (like the
manifest), we always pass a log_number of 0 and false.

Signed-off-by: Sage Weil <sage@redhat.com>
2015-10-18 21:24:32 -04:00
Alexey Maykov e1a09a7703 Implementation for GetPropertiesOfTablesInRange
Summary: In MyRocks, it is sometimes important to get propeties only for the subset of the database. This diff implements the API in RocksDB.

Test Plan: ran the GetPropertiesOfTablesInRange

Reviewers: rven, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48651
2015-10-17 13:34:43 -07:00