Summary:
This patch implements DBOptions deserialization and improve
the current implementation of DBOptions serialization by
using a static structure that stores the offset of each
DBOptions member variables to perform serialization and
deserialization instead of using tons of if-then-branch
to determine the mapping between string and variables.

Test Plan: Added test in options_test.cc

Reviewers: igor, anthony, sdong, IslamAbdelRahman

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D44097

Summary:
HashCuckooRep::ApproximateMemoryUsage() previously return
std::numeric_limits<size_t>::max() when it cannot accept more
entries.  This patch makes it return a more reasonable estimation.

This change is necessary in order to make GetIntProperty("rocksdb.cur-size-all-mem-tables")
handles HashCuckooRep properly in diff https://reviews.facebook.net/D44229.

Test Plan: db_test

Reviewers: sdong, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D44241

Summary:
In D43239 (https://reviews.facebook.net/D43239) there is an
assertion to make sure a subcompaction's output is never empty at the
end of execution. This assertion however breaks the build because some
tests lead to exactly that scenario. So instead I have altered the logic
to handle this case instead of just failing the assertion.

The reason that it is possible for a subcompaction's output to be empty is
that during a sequential execution of subcompactions, if a user aborts the
compaction job then some of the later subcompactions to be executed may
have yet to process any keys and therefore have yet to generate output files.
This becomes very rare once the subcompactions are executed in parallel,
but for now they are still sequential so the case is possible when there is an
early termination, as in some of the tests.

Test Plan: ./db_test  ./db_compaction_test

Reviewers: sdong, igor, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D44877

Summary:
In prepration for running multiple threads at the same time during
a compaction job, this patch assigns each subcompaction its own state
(instead of sharing the one global CompactionState). Each subcompaction then
uses this state to update its statistics, keep track of its snapshots, etc.
during the course of execution. Then at the end of all the executions the
statistics are aggregated across the subcompactions so that the final result
is the same as if only one larger compaction had run.

Test Plan: ./db_test  ./db_compaction_test  ./compaction_job_test

Reviewers: sdong, anthony, igor, noetzli, yhchiang

Reviewed By: yhchiang

Subscribers: MarkCallaghan, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43239

Summary:
While working on supporting mixing merge operators with
single deletes ( https://reviews.facebook.net/D43179 ),
I realized that returning and dealing with merge results
can be made simpler. Submitting this as a separate diff
because it is not directly related to single deletes.

Before, callers of merge helper had to retrieve the merge
result in one of two ways depending on whether the merge
was successful or not (success = result of merge was single
kTypeValue). For successful merges, the caller could query
the resulting key/value pair and for unsuccessful merges,
the result could be retrieved in the form of two deques of
keys and values. However, with single deletes, a successful merge
does not return a single key/value pair (if merge
operands are merged with a single delete, we have to generate
a value and keep the original single delete around to make
sure that we are not accidentially producing a key overwrite).
In addition, the two existing call sites of the merge
helper were taking the same actions independently from whether
the merge was successful or not, so this patch simplifies that.

Test Plan: make clean all check

Reviewers: rven, sdong, yhchiang, anthony, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43353

Summary: In internal stats, remember read latency histogram, if statistics is enabled. It can be retrieved from DB::GetProperty() with "rocksdb.dbstats" property, if it is enabled.

Test Plan: Manually run db_bench and prints out "rocksdb.dbstats" by hand and make sure it prints out as expected

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

Reviewed By: yhchiang

Subscribers: MarkCallaghan, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D44193

Summary:
This diff allows a Writer to join the next write batch group
without acquiring any locks. Waiting is performed via a per-Writer mutex,
so all of the non-leader writers never need to acquire the db mutex.
It is now possible to join a write batch group after the leader has been
chosen but before the batch has been constructed. This diff doesn't
increase parallelism, but reduces synchronization overheads.

For some CPU-bound workloads (no WAL, RAM-sized working set) this can
substantially reduce contention on the db mutex in a multi-threaded
environment.  With T=8 N=500000 in a CPU-bound scenario (see the test
plan) this is good for a 33% perf win.  Not all scenarios see such a
win, but none show a loss.  This code is slightly faster even for the
single-threaded case (about 2% for the CPU-bound scenario below).

Test Plan:
1. unit tests
2. COMPILE_WITH_TSAN=1 make check
3. stress high-contention scenarios with db_bench -benchmarks=fillrandom -threads=$T -batch_size=1 -memtablerep=skip_list -value_size=0 --num=$N -level0_slowdown_writes_trigger=9999 -level0_stop_writes_trigger=9999 -disable_auto_compactions --max_write_buffer_number=8 -max_background_flushes=8 --disable_wal --write_buffer_size=160000000

Reviewers: sdong, igor, rven, ljin, yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43887

Summary:
Add options.compaction_measure_io_stats to print out / pass to listener accumulated time spent on write calls. Example outputs in info logs:

2015/08/12-16:27:59.463944 7fd428bff700 (Original Log Time 2015/08/12-16:27:59.463922) EVENT_LOG_v1 {"time_micros": 1439422079463897, "job": 6, "event": "compaction_finished", "output_level": 1, "num_output_files": 4, "total_output_size": 6900525, "num_input_records": 111483, "num_output_records": 106877, "file_write_nanos": 15663206, "file_range_sync_nanos": 649588, "file_fsync_nanos": 349614797, "file_prepare_write_nanos": 1505812, "lsm_state": [2, 4, 0, 0, 0, 0, 0]}

Add two more counters in iostats_context.

Also add a parameter of db_bench.

Test Plan: Add a unit test. Also manually verify LOG outputs in db_bench

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D44115

Summary: Change master version to 3.14

Test Plan: simple change

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

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D44187

Add a 'tools' target.

My use case is to build the rocksdb static library and tools, and
ideally I'd like to not spend time building the shared library and other
targets that I won't use.

Summary: Iterator has a bug: if a child iterator reaches its end, and user issues a Prev(), and just before SeekToLast() of the child iterator is called, some extra rows is added in the end, the position of iterator can be misplaced.

Test Plan: Run the tests with or without valgrind

Reviewers: rven, yhchiang, IslamAbdelRahman, anthony

Reviewed By: anthony

Subscribers: tnovak, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43671

Summary: RandomRWFile is not used anywhere in out code base, this patch remove RandomRWFile

Test Plan:
make check -j64
USE_CLANG=1 make all -j64
OPT=-DROCKSDB_LITE make release -j64

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

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D44091

Summary:
Clean up transactions to use the new RollbackToSavePoint api in WriteBatchWithIndex.

Note, this diff depends on Pessimistic Transactions diff and ManagedSnapshot diff (D40869 and D43293).

Test Plan: unit tests

Reviewers: rven, yhchiang, kradhakrishnan, spetrunia, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43371

Summary:
Based on feedback from spetrunia, we should better differentiate error statuses for transaction failures.

https://github.com/MySQLOnRocksDB/mysql-5.6/issues/86#issuecomment-124605954

Test Plan: unit tests

Reviewers: rven, kradhakrishnan, spetrunia, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43323

Summary:
Initial implementation of Pessimistic Transactions.  This diff contains the api changes discussed in D38913.  This diff is pretty large, so let me know if people would prefer to meet up to discuss it.

MyRocks folks:  please take a look at the API in include/rocksdb/utilities/transaction[_db].h and let me know if you have any issues.

Also, you'll notice a couple of TODOs in the implementation of RollbackToSavePoint().  After chatting with Siying, I'm going to send out a separate diff for an alternate implementation of this feature that implements the rollback inside of WriteBatch/WriteBatchWithIndex.  We can then decide which route is preferable.

Next, I'm planning on doing some perf testing and then integrating this diff into MongoRocks for further testing.

Test Plan: Unit tests, db_bench parallel testing.

Reviewers: igor, rven, sdong, yhchiang, yoshinorim

Reviewed By: sdong

Subscribers: hermanlee4, maykov, spetrunia, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D40869

Summary:
Under certain conditions (disable compression) the compactions that are created in compaction_job_test will pass the trivial_move conditions
This will cause problems since we assert that we dont run a compaction if it's a trivial move
https://github.com/facebook/rocksdb/blob/master/db/compaction_job.cc#L144-L147

for example when we disable compression, compactions become a valid trivial move and the assert fails
https://ci-builds.fb.com/view/rocksdb/job/rocksdb_no_compression/180/console

Test Plan: compaction_job_test

Reviewers: sdong, yhchiang, noetzli, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43983

Test Plan: untested

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D44049

Summary:
This patch fixes the following clang-build error in util/thread_local.cc by using a cleaner macro blocker:

12:26:31 util/thread_local.cc:157:19: error: declaration shadows a static data member of 'rocksdb::ThreadLocalPtr::StaticMeta' [-Werror,-Wshadow]
12:26:31       ThreadData* tls_ =
12:26:31                   ^
12:26:31 util/thread_local.cc:19:66: note: previous declaration is here
12:26:31 __thread ThreadLocalPtr::ThreadData* ThreadLocalPtr::StaticMeta::tls_ = nullptr;
12:26:31                                                                  ^

Test Plan: db_test

Reviewers: sdong, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D44043

Summary: Add a new option that all LoadTableHandlers to use multiple threads to load files on DB Open and Recover

Test Plan:
make check -j64
COMPILE_WITH_TSAN=1 make check -j64
DISABLE_JEMALLOC=1 make all valgrind_check -j64 (still running)

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

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43755

Summary:
While working on single delete support for db_bench, I realized that
db_bench/db_stress contain a bunch of duplicate code related to
copmression and found some typos. This patch removes duplicate code,
typos and a redundant #ifndef in internal_stats.cc.

Test Plan: make db_stress && make db_bench && ./db_bench --benchmarks=compress,uncompress

Reviewers: yhchiang, sdong, rven, anthony, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43965

Summary:
Our linters assume that clang-format is installed at /mnt/vol/engshare/admin/scripts/clang-format and flint is installed at /home/engshare/tools/flint. This makes them fail on non-fb machines. This change will:
* if clang-format is not on a specified path, it will try running generic clang-format. Linters will still fail if clang-format is not installed, but this shouldn't be a big issue, since it's pretty easy to install it.
* flint will not be run if /home/engshare/tools/flint is not present

Test Plan: Made a change on a mac machine. Ran `arc lint`. No failures observed.

Reviewers: aekmekji, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D44031

Summary:
Key comparison is the single largest CPU user for CPU-bound
workloads. This diff reduces the number of comparisons in two ways.

The first is that it moves predecessor array gathering from
FindGreaterOrEqual to FindLessThan, so that FindGreaterOrEqual can
return immediately if compare_ returns 0.  As part of this change I
moved the sequential insertion optimization into Insert, to remove the
undocumented (and smelly) requirement that prev must be equal to prev_
if it is non-null.

The second optimization is that all of the search functions skip calling
compare_ when moving to a lower level that has the same Next pointer.
With a branching factor of 4 we would expect this to happen 1/4 of
the time.

On a single-threaded CPU-bound workload (-benchmarks=fillrandom -threads=1
-batch_size=1 -memtablerep=skip_list -value_size=0 --num=1600000
-level0_slowdown_writes_trigger=9999 -level0_stop_writes_trigger=9999
-disable_auto_compactions --max_write_buffer_number=8
-max_background_flushes=8 --disable_wal --write_buffer_size=160000000)
on my dev server this is good for a 7% perf win.

Test Plan: unit tests

Reviewers: rven, ljin, yhchiang, sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43233

Summary:
This patch provides a simplier solution to the memory leak
issue identified in patch https://reviews.facebook.net/D43677,
where a static function local variable can be used instead of
using a global static unique_ptr.

Test Plan: run db_stress on mac

Reviewers: igor, sdong, anthony, IslamAbdelRahman, maykov

Reviewed By: maykov

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43995

Summary:
This was motivated by t7518166. checkCpp crashes on db_test.cc because the file is too big :(

Couple of changes:
* Added clang-format linter. Now we can catch all code that is not formatted correctly.
* Added Howtoeven in our list of linters
* Replaced cpplint with flint
* Removed checkCpp lint. Nobody ownes it and it doesn't work on db_test.cc

Test Plan: Made a random lint error and `arc lint`. Saw an error.

Reviewers: yhchiang, kradhakrishnan, anthony, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41949

Summary:
https://ci-builds.fb.com/view/rocksdb/job/rocksdb_clang_build/893/console
Fixing clang build

Test Plan:
make clean
USE_CLANG=1 make all -j64

Reviewers: sdong, noetzli, yhchiang, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43959

Summary:
wal_recovery_mode setting was not written to LOG. This diff
adds the log message

Test Plan: manually checked

Reviewers: kradhakrishnan, sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43953

Summary:
Changed compaction_job_test to support better/more thorough
tests and added two tests. Also changed MockFileContents
to order using InternalKeyComparator.

Test Plan: make compaction_job_test && ./compaction_job_test; make all && make check

Reviewers: sdong, rven, igor, yhchiang, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42837

Summary: Start measuring time spent before BackgroundEmptyTrash starts

Test Plan: delete_scheduler_test

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43857

Summary: Check in a simple auto-build manfiest so that developers can issue ad-hoc build for Windows in Appveyor.

Test Plan: Run it in test branch test_appveyor and it works well.

Reviewers: kradhakrishnan, rven, anthony, IslamAbdelRahman, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43839

Fix OSX + Windows build

Commit 257ee895 added a static destruction helper to avoid notional
"leaks" of TLS on main thread exit. This helper fails to compile on
OS X (and presumably Windows, though I haven't checked), which lacks
the __thread storage class StaticMeta::tls_ member.

This patch fixes the builds. Do note that the static cleanup mechanism
may be somewhat brittle and atexit(3) may be a more suitable approach
to releasing the main thread's TLS if it's highly desirable for this
memory to not be reported "reachable" by Valgrind at exit.

Summary: Implemented this simple wrapper for something else I was working on.  Seemed like it makes sense to expose it instead of burying it in some random code.

Test Plan: added test

Reviewers: rven, kradhakrishnan, sdong, yhchiang

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43293

Summary:
MyRocks valgrind run was showing memory leaks. The fixes are mostly self-explaining.
There is only a single usage of ThreadLocalPtr. Potentially, we may think about replacing this use with thread_local, but it will be a bigger change. Another option to consider is using thread_local instead of __thread in ThreadLocalPtr implementation. This way, tls_ can be stored using std::unique_ptr and no destructor would be required.

Test Plan:
 - make check
 - MyRocks valgrind run doesn't report leaks

Reviewers: rven, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43677

Summary: Prepare release notes for 3.13.

Test Plan: Text only

Reviewers: yhchiang, IslamAbdelRahman, rven, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43665

Summary: Use shared_ptr instead of deleting in destructor

Test Plan: DISABLE_JEMALLOC=1 make delete_scheduler_test -j64 && valgrind --error-exitcode=2 --leak-check=full ./delete_scheduler_test

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43659

Summary:
Visual Studio complains about deque<LogWriterNumber> because LogWriterNumber is non-copyable for its unique_ptr member writer. Move away from it, and do explit free.
It is less safe but I can't think of a better way to unblock it.

Test Plan: valgrind check test

Reviewers: anthony, IslamAbdelRahman, kolmike, rven, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43647

Summary:
When seeking to the last occurrence of a key with sequence number 0, db_iter
ends up in an endless loop because it seeks to type kValueTypeForSeek
which is larger than kTypeDeletion/kTypeValue. Added test case that triggers
the behavior.

Test Plan: make clean all check

Reviewers: igor, rven, anthony, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43653

Summary: util/delete_scheduler_impl.cc is missing CMakeLists.txt, which fails Windows build. Add it.

Test Plan: Build in both of Windows and Linux

Reviewers: anthony, rven, yhchiang, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43641

Summary:
Provide a way for users to know more detailed ditribution of a histogram metrics. Example outputs:

Manually add statement
  fprintf(stdout, "%s\n", dbstats->getHistogramString(SST_READ_MICROS).c_str());
Will print out something like:

Count: 989151  Average: 1.7659  StdDev: 1.52
Min: 0.0000  Median: 1.2071  Max: 860.0000
Percentiles: P50: 1.21 P75: 1.70 P99: 5.12 P99.9: 13.67 P99.99: 21.70
------------------------------------------------------
[       0,       1 )   390839  39.513%  39.513% ########
[       1,       2 )   500918  50.641%  90.154% ##########
[       2,       3 )    79358   8.023%  98.177% ##
[       3,       4 )     6297   0.637%  98.813%
[       4,       5 )     1712   0.173%  98.986%
[       5,       6 )     1134   0.115%  99.101%
[       6,       7 )     1222   0.124%  99.224%
[       7,       8 )     1529   0.155%  99.379%
[       8,       9 )     1264   0.128%  99.507%
[       9,      10 )      988   0.100%  99.607%
[      10,      12 )     1378   0.139%  99.746%
[      12,      14 )     1828   0.185%  99.931%
[      14,      16 )      410   0.041%  99.972%
[      16,      18 )       72   0.007%  99.980%
[      18,      20 )       67   0.007%  99.986%
[      20,      25 )      106   0.011%  99.997%
[      25,      30 )       24   0.002%  99.999%
[      30,      35 )        1   0.000% 100.000%
[     250,     300 )        2   0.000% 100.000%
[     300,     350 )        1   0.000% 100.000%
[     800,     900 )        1   0.000% 100.000%

Test Plan: Manually add a print in db_bench and make sure it prints out as expected. Will add some codes to cover the function

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43611