Summary:
gtest does not use exceptions to fail a unit test by design, and `ASSERT*`s are implemented using `return`. As a consequence we cannot use `ASSERT*` in a function that does not return `void` value ([[ https://code.google.com/p/googletest/wiki/AdvancedGuide#Assertion_Placement | 1]]), and have to fix our existing code. This diff does this in a generic way, with no manual changes.

In order to detect all existing `ASSERT*` that are used in functions that doesn't return void value, I change the code to generate compile errors for such cases.

In `util/testharness.h` I defined `EXPECT*` assertions, the same way as `ASSERT*`, and redefined `ASSERT*` to return `void`. Then executed:

```lang=bash
% USE_CLANG=1 make all -j55 -k 2> build.log
% perl -naF: -e 'print "-- -number=".$F[1]." ".$F[0]."\n" if  /: error:/' \
build.log | xargs -L 1 perl -spi -e 's/ASSERT/EXPECT/g if $. == $number'
% make format
```
After that I reverted back change to `ASSERT*` in `util/testharness.h`. But preserved introduced `EXPECT*`, which is the same as `ASSERT*`. This will be deleted once switched to gtest.

This diff is independent and contains manual changes only in `util/testharness.h`.

Test Plan:
Make sure all tests are passing.
```lang=bash
% USE_CLANG=1 make check
```

Reviewers: igor, lgalanis, sdong, yufei.zhu, rven, meyering

Reviewed By: meyering

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D33333

Summary:
On RocksDB, when there are multiple instances doing
flushes/compactions in the background, the close call takes a long time
because the flushes/compactions need to complete before the database can
shut down. If another instance is using the background threads and the compaction for this instance is in the queue since it has been scheduled, we still cannot shutdown. We now remove the scheduled background tasks which have not yet started running, so that shutdown is speeded up.

Test Plan: DB Test added.

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D33741

Summary: These changes are necessary to make tests look more generic, and avoid feature conflicts with gtest.

Test Plan:
Make sure no build errors, and all test are passing.
```
% make check
```

Reviewers: igor, meyering

Reviewed By: meyering

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35145

Summary:
The output did not have space for 6-digit file counts or for 3-digit
counts of files being compacted. This adds space for that while preserving
existing alignment. See https://gist.github.com/mdcallag/0a61c6a18dd467224c11

Task ID: #

Blame Rev:

Test Plan:
run db_bench, look at output

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D35091

Summary: I had hard time understanding these big numbers. Here's how the output looks like now: https://gist.github.com/igorcanadi/4c39c17685049584a992

Test Plan: db_bench

Reviewers: sdong, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35073

Summary:
Per-level stall times are the suggested stall time, not the actual stall time so this change stops printing them
both in the per-level output lines and in the summary. Also changed output for total stall time to include units
in all cases. The new output looks like:
Level   Files   Size(MB) Score Read(GB)  Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) Moved(GB) W-Amp Rd(MB/s) Wr(MB/s) Comp(sec) Comp(cnt) Avg(sec) Stall(cnt)    RecordIn   RecordDrop
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  L0     4/1          7   0.8      0.0     0.0      0.0       0.6      0.6       0.0   0.0      0.0     12.9        50       352    0.141        882            0            0
  L1     5/0          9   0.9      0.0     0.0      0.0       0.0      0.0       0.6   0.0      0.0      0.0         0         0    0.000          0            0            0
  L2    54/0         99   1.0      0.0     0.0      0.0       0.0      0.0       0.6   0.0      0.0      0.0         0         0    0.000          0            0            0
  L3   289/0        527   0.5      0.0     0.0      0.0       0.0      0.0       0.5   0.0      0.0      0.0         0         0    0.000          0            0            0
 Sum   352/1        642   0.0      0.0     0.0      0.0       0.6      0.6       1.7   1.0      0.0     12.9        50       352    0.141        882            0            0
 Int     0/0          0   0.0      0.0     0.0      0.0       0.0      0.0       0.0   1.0      0.0     15.5         0         3    0.118          7            0            0
Flush(GB): accumulative 0.627, interval 0.005
Stalls(count): 0 level0_slowdown, 0 level0_numfiles, 882 memtable_compaction, 0 leveln_slowdown_soft, 0 leveln_slowdown_hard

Task ID: #6493861

Blame Rev:

Test Plan:
run db_bench, look at output

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D35085

Summary: Fixed the unit-test issue in PreShutdownCompactionMiddle

Test Plan: export ROCKSDB_TESTS=PreShutdownCompactionMiddle

Reviewers: rven, sdong, igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35061

Summary: Fix the issue in PreShutdownMultipleCompaction

Test Plan:
export ROCKSDB_TESTS=PreShutdownMultipleCompaction
./db_test

Reviewers: rven, sdong, igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35055

Summary:
The preshutdown tests check for stopped compactions/flushes.
Removing stalls on the write path.

Test Plan: DBTests.PreShutdown*

Reviewers: yhchiang, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35037

Summary: See t6489044

Test Plan: compiles

Reviewers: MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34977

Summary:
Improve the robustness of ThreadStatusSingleCompaction
by ensuring the number of files flushed in the test.

Test Plan:
export ROCKSDB_TESTS=ThreadStatus
./db_test

Reviewers: sdong, igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35019

Summary:
Fix the deadlock issue in ThreadStatusSingleCompaction.

In the previous version of ThreadStatusSingleCompaction, the compaction
thread will wait for a SYNC_POINT while its db_mutex is held.  However,
if the test hasn't finished its Put cycle while a compaction is running,
a deadlock will happen in the test.

Test Plan:
export ROCKSDB_TESTS=ThreadStatus
./db_test

Reviewers: sdong, igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35001

Summary: The test depends on snappy to be used. Skip the test if it is not supported.

Test Plan: Run the test

Reviewers: meyering, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D34995

Summary:
Fix a typo / test failure in ThreadStatusSingleCompaction

Test Plan:
export ROCKSDB_TESTS=ThreadStatus
./db_test

Summary: Currently, we have `ifdef SNAPPY` around bunch of db_test code. Some tests that don't even use compression are also blocked when running system doesn't have snappy. This also causes hard-to-catch bugs, like D34983. We should dynamically figure out if compression is supported or not.

Test Plan: compiles

Reviewers: sdong, meyering

Reviewed By: meyering

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34989

Summary: Allow GetThreadList() to report operation stage.

Test Plan:
  ./thread_list_test
  ./db_bench --benchmarks=fillrandom --num=100000 --threads=40 \
    --max_background_compactions=10 --max_background_flushes=3 \
    --thread_status_per_interval=1000 --key_size=16 --value_size=1000 \
    --num_column_families=10

  export ROCKSDB_TESTS=ThreadStatus
  ./db_test

Sample output
          ThreadID ThreadType                    cfName    Operation        OP_StartTime    ElapsedTime                                         Stage        State
   140116265861184    Low Pri
   140116270055488    Low Pri
   140116274249792   High Pri column_family_name_000005        Flush 2015/03/10-14:58:11           0 us                    FlushJob::WriteLevel0Table
   140116400078912    Low Pri column_family_name_000004   Compaction 2015/03/10-14:58:11           0 us     CompactionJob::FinishCompactionOutputFile
   140116358135872    Low Pri column_family_name_000006   Compaction 2015/03/10-14:58:10           1 us     CompactionJob::FinishCompactionOutputFile
   140116341358656    Low Pri
   140116295221312   High Pri                   default        Flush 2015/03/10-14:58:11           0 us                    FlushJob::WriteLevel0Table
   140116324581440    Low Pri column_family_name_000009   Compaction 2015/03/10-14:58:11           0 us      CompactionJob::ProcessKeyValueCompaction
   140116278444096    Low Pri
   140116299415616    Low Pri column_family_name_000008   Compaction 2015/03/10-14:58:11           0 us     CompactionJob::FinishCompactionOutputFile
   140116291027008   High Pri column_family_name_000001        Flush 2015/03/10-14:58:11           0 us                    FlushJob::WriteLevel0Table
   140116286832704    Low Pri column_family_name_000002   Compaction 2015/03/10-14:58:11           0 us     CompactionJob::FinishCompactionOutputFile
   140116282638400    Low Pri

Reviewers: rven, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34683

Summary:
Here's my proposal for making our LOGs easier to read by machines.

The idea is to dump all events as JSON objects. JSON is easy to read by humans, but more importantly, it's easy to read by machines. That way, we can parse this, load into SQLite/mongo and then query or visualize.

I started with table_create and table_delete events, but if everybody agrees, I'll continue by adding more events (flush/compaction/etc etc)

Test Plan:
Ran db_bench. Observed:
2015/01/15-14:13:25.788019 1105ef000 EVENT_LOG_v1 {"time_micros": 1421360005788015, "event": "table_file_creation", "file_number": 12, "file_size": 1909699}
2015/01/15-14:13:25.956500 110740000 EVENT_LOG_v1 {"time_micros": 1421360005956498, "event": "table_file_deletion", "file_number": 12}

Reviewers: yhchiang, rven, dhruba, MarkCallaghan, lgalanis, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D31647

Summary:
we are using uint64_t for Wnew this is not correct since this value can be negative
https://github.com/facebook/rocksdb/issues/535

Test Plan: run db_bench and check what happens when Wnew is -ve

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D34935

Summary:
The tests using sync_point for intent to shutdown stop
compaction and this results in stalls if too many rows are written. We
now limit the number of rows written to prevent stalls, since the focus
of the test is to cancel background work, which is being correctly
tested. This fixes a Jenkins issue.

Test Plan: DBTest.PreShutdown*

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34893

Summary:
Fixing segmentation fault when running db_bench

This seg fault happens because num_created is used without being initialized

Test Plan:
running db_bench using these arguments
bpl=10485760;overlap=10;mcz=2;del=300000000;levels=6;ctrig=4; delay=8; stop=12; wbn=3; mbc=20; mb=67108864;wbs=134217728; dds=0; sync=0; r=1000000; t=1; vs=800; bs=65536; cs=1048576; of=500000; si=1000000; ./db_bench --benchmarks=overwrite --disable_seek_compaction=1 --mmap_read=0 --statistics=1 --histogram=1 --num=$r --threads=$t --value_size=$vs --block_size=$bs --cache_size=$cs --bloom_bits=10 --cache_numshardbits=4 --open_files=$of --verify_checksum=1 --db=/home/tec/koko/ --sync=$sync --disable_wal=1 --compression_type=zlib --stats_interval=$si --compression_ratio=0.5 --disable_data_sync=$dds --write_buffer_size=$wbs --target_file_size_base=$mb --max_write_buffer_number=$wbn --max_background_compactions=$mbc --level0_file_num_compaction_trigger=$ctrig --level0_slowdown_writes_trigger=$delay --level0_stop_writes_trigger=$stop --num_levels=$levels --delete_obsolete_files_period_micros=$del --min_level_to_compress=$mcz --max_grandparent_overlap_factor=$overlap --stats_per_interval=1 --max_bytes_for_level_base=$bpl --use_existing_db=1

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D34881

Change the way options.compression_per_level is used when options.level_compaction_dynamic_level_bytes=true

Summary:
Change the way options.compression_per_level is used when options.level_compaction_dynamic_level_bytes=true so that options.compression_per_level[1] determines compression for the level L0 is merged to, options.compression_per_level[2] to the level after that, etc.

Test Plan: run all tests

Reviewers: rven, yhchiang, kradhakrishnan, igor

Reviewed By: igor

Subscribers: yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D34431

Summary: Fixed a bug where CompactFiles won't delete obsolete files until flush.

Test Plan:
./compact_files_test
export ROCKSDB_TESTS=CompactFiles
./db_test

Reviewers: rven, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34671

Summary: Use a better way to map from a key with locality to a random location. Now with the same -read_random_exp_range setting, hit rate drops, which it is expected.

Test Plan: ./db_bench --benchmarks=readrandom -statistics -use_existing_db -cache_size=5000000 --read_random_exp_range=<multiple_values>

Reviewers: MarkCallaghan, kradhakrishnan, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D34761

Summary:
Provide an API which enables users to infor Rocksdb that it is
shutting down.

Test Plan: db_test

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34617

Summary: Got it working by some voodoo programming

Test Plan: works!

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34611

Summary: Allow GetThreadList() to report the start time of the current operation.

Test Plan:
./db_bench --benchmarks=fillrandom --num=100000 --threads=40 \
  --max_background_compactions=10 --max_background_flushes=3 \
  --thread_status_per_interval=1000 --key_size=16 --value_size=1000 \
  --num_column_families=10

Sample output:
          ThreadID ThreadType                    cfName    Operation        OP_StartTime         State
   140338840797248   High Pri column_family_name_000003        Flush 2015/03/09-17:49:59
   140338844991552   High Pri column_family_name_000004        Flush 2015/03/09-17:49:59
   140338849185856    Low Pri
   140338983403584    Low Pri
   140339008569408    Low Pri
   140338861768768    Low Pri
   140338924683328    Low Pri
   140338899517504    Low Pri
   140338853380160    Low Pri
   140338882740288    Low Pri
   140338865963072   High Pri column_family_name_000006        Flush 2015/03/09-17:49:59
   140338954043456    Low Pri
   140338857574464    Low Pri

Reviewers: igor, rven, sdong

Reviewed By: sdong

Subscribers: lgalanis, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34689

Summary: Introduce parameter -read_random_exp_range in db_bench to provide some key skewness in readrandom and multireadrandom benchmarks. It will helpful to cover block cache better.

Test Plan:
Run benchmarks with this new parameter. I can clearly see block cache hit rate change while I increase this value (DB size is about 66MB):

./db_bench --benchmarks=readrandom -statistics -use_existing_db -cache_size=5000000 --read_random_exp_range=0.0
rocksdb.block.cache.data.miss COUNT : 958418
rocksdb.block.cache.data.hit COUNT : 41582

./db_bench --benchmarks=readrandom -statistics -use_existing_db -cache_size=5000000 --read_random_exp_range=5.0
rocksdb.block.cache.data.miss COUNT : 819518
rocksdb.block.cache.data.hit COUNT : 180482

./db_bench --benchmarks=readrandom -statistics -use_existing_db -cache_size=5000000 --read_random_exp_range=10.0
rocksdb.block.cache.data.miss COUNT : 450479
rocksdb.block.cache.data.hit COUNT : 549521

./db_bench --benchmarks=readrandom -statistics -use_existing_db -cache_size=5000000 --read_random_exp_range=20.0
rocksdb.block.cache.data.miss COUNT : 223192
rocksdb.block.cache.data.hit COUNT : 776808

Reviewers: MarkCallaghan, kradhakrishnan, yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D34629

Summary: I want to be able to set this through mongo config.

Test Plan: added unit test

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34599

Summary:
Add --thread_status_per_interval to db_bench, which allows
db_bench to optionally enable print the current thread status
periodically.

Test Plan:
./db_bench --benchmarks=fillrandom --num=100000 --threads=40 --max_background_compactions=10 --max_background_flushes=3 --thread_status_per_interval=1000 --key_size=16 --value_size=1000 --num_column_families=10

Sample output:
          ThreadID ThreadType                         dbName                     cfName       Operation           State
   140281571770432    Low Pri
   140281575964736   High Pri  /tmp/rocksdbtest-5297/dbbench  column_family_name_000001           Flush
   140281710182464    Low Pri  /tmp/rocksdbtest-5297/dbbench  column_family_name_000008      Compaction
   140281638879296    Low Pri  /tmp/rocksdbtest-5297/dbbench  column_family_name_000007      Compaction
   140281592741952    Low Pri
   140281580159040   High Pri  /tmp/rocksdbtest-5297/dbbench  column_family_name_000002           Flush
   140281676628032    Low Pri  /tmp/rocksdbtest-5297/dbbench  column_family_name_000006      Compaction
   140281584353344    Low Pri
   140281622102080    Low Pri  /tmp/rocksdbtest-5297/dbbench  column_family_name_000009      Compaction
   140281605324864    Low Pri  /tmp/rocksdbtest-5297/dbbench  column_family_name_000004      Compaction
   140281601130560   High Pri  /tmp/rocksdbtest-5297/dbbench                    default           Flush
   140281596936256    Low Pri
   140281588547648    Low Pri

Reviewers: igor, rven, sdong

Reviewed By: rven

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D34515

Summary: Fix a bug in stall time counter.  Improve its output format.

Test Plan:
export ROCKSDB_TESTS=Timeout
./db_test

./db_bench --benchmarks=fillrandom --stats_interval=10000 --statistics=true --stats_per_interval=1 --num=1000000 --threads=4 --level0_stop_writes_trigger=3 --level0_slowdown_writes_trigger=2

sample output:
    Uptime(secs): 35.8 total, 0.0 interval
    Cumulative writes: 359590 writes, 359589 keys, 183047 batches, 2.0 writes per batch, 0.04 GB user ingest, stall seconds: 1786.008 ms
    Cumulative WAL: 359591 writes, 183046 syncs, 1.96 writes per sync, 0.04 GB written
    Interval writes: 253 writes, 253 keys, 128 batches, 2.0 writes per batch, 0.0 MB user ingest, stall time: 0 us
    Interval WAL: 253 writes, 128 syncs, 1.96 writes per sync, 0.00 MB written

Reviewers: MarkCallaghan, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34275

options.level_compaction_dynamic_level_bytes to allow RocksDB to pick size bases of levels dynamically.

Summary:
When having fixed max_bytes_for_level_base, the ratio of size of largest level and the second one can range from 0 to the multiplier. This makes LSM tree frequently irregular and unpredictable. It can also cause poor space amplification in some cases.

In this improvement (proposed by Igor Kabiljo), we introduce a parameter option.level_compaction_use_dynamic_max_bytes. When turning it on, RocksDB is free to pick a level base in the range of (options.max_bytes_for_level_base/options.max_bytes_for_level_multiplier, options.max_bytes_for_level_base] so that real level ratios are close to options.max_bytes_for_level_multiplier.

Test Plan: New unit tests and pass tests suites including valgrind.

Reviewers: MarkCallaghan, rven, yhchiang, igor, ikabiljo

Reviewed By: ikabiljo

Subscribers: yoshinorim, ikabiljo, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D31437

Summary:
fix typo

Task ID: #

Blame Rev:

Test Plan:
Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D34251

Summary: As title

Test Plan: compiles

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34191

Summary:
    Summary:
    Added a new option to ColumnFamllyOptions  - optimize_filters_for_hits. This option can be used in the case where most
    accesses to the store are key hits and we dont need to optimize performance for key misses.
    This is useful when you have a very large database and most of your lookups succeed.  The option allows the store to
     not store and use filters in the last level (the largest level which contains data). These filters can take a large amount of
     space for large databases (in memory and on-disk). For the last level, these filters are only useful for key misses and not
     for key hits. If we are not optimizing for key misses, we can choose to not store these filters for that level.

    This option is only provided for BlockBasedTable. We skip the filters when we are compacting

Test Plan:
1. Modified db_test toalso run tests with an additonal option (skip_filters_on_last_level)
 2. Added another unit test to db_test which specifically tests that filters are being skipped

Reviewers: rven, igor, sdong

Reviewed By: sdong

Subscribers: lgalanis, yoshinorim, MarkCallaghan, rven, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D33717

Summary:
When using latest clang (3.6 or 3.7/trunck) rocksdb is failing with many errors. Almost all of them are missing override errors. This diff adds missing override keyword. No manual changes.

Prerequisites: bear and clang 3.5 build with extra tools

```lang=bash
% USE_CLANG=1 bear make all # generate a compilation database http://clang.llvm.org/docs/JSONCompilationDatabase.html
% clang-modernize -p . -include . -add-override
% make format
```

Test Plan:
Make sure all tests are passing.
```lang=bash
% #Use default fb code clang.
% make check
```
Verify less error and no missing override errors.
```lang=bash
% # Have trunk clang present in path.
% ROCKSDB_NO_FBCODE=1 CC=clang CXX=clang++ make
```

Reviewers: igor, kradhakrishnan, rven, meyering, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34077

Summary:
An old commit (482401) changed DoWrite to use the value of --writes rather
than --num to determine the range for keys. This restores the old and correct
behavior which is to limit it using --num.

Task ID: #6353043

Blame Rev:

Test Plan:
run db_bench

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D34065

Summary:
In a release build, a member was not being accessed. This
member was only being accessed in a debug build. We now add an accessor
function for this member and the buid succeeds.

Test Plan: build release/unity/debug on linux/mac

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34035

This reverts commit bd339a97.

Conflicts:
	db/managed_iterator.cc