Summary:
With this change, we use L1 and up to store compaction outputs in universal compaction.
The compaction pick logic stays the same. Outputs are stored in the largest "level" as possible.

If options.num_levels=1, it behaves all the same as now.

Test Plan:
1) convert most of existing unit tests for universal comapaction to include the option of one level and multiple levels.
2) add a unit test to cover parallel compaction in universal compaction and run it in one level and multiple levels
3) add unit test to migrate from multiple level setting back to one level setting
4) add a unit test to insert keys to trigger multiple rounds of compactions and verify results.

Reviewers: rven, kradhakrishnan, yhchiang, igor

Reviewed By: igor

Subscribers: meyering, leveldb, MarkCallaghan, dhruba

Differential Revision: https://reviews.facebook.net/D34539

Summary:
Cleaning up log files can do heavy IO, since we call ftruncate() in the destructor. We don't want to call ftruncate() in user threads.

This diff moves cleaning to background threads (flush and compaction)

Test Plan: make check, will also run valgrind

Reviewers: yhchiang, rven, MarkCallaghan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D36177

Summary:
Assign the string properties to const string variables under the
DB::Properties namespace. This helps catch typos during compilation and
also consolidates the property definition in one place.

Test Plan: Run rocksdb unit tests

Reviewers: sdong, yoshinorim, igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D35991

Summary: It's useful to know if we have compression support or no

Test Plan:
Observed this in my LOG:

      2015/03/26-10:34:35.460681 7f5b322b7840 Snappy supported
      2015/03/26-10:34:35.460682 7f5b322b7840 Zlib supported
      2015/03/26-10:34:35.460686 7f5b322b7840 Bzip supported
      2015/03/26-10:34:35.460687 7f5b322b7840 LZ4 NOT supported

Reviewers: sdong, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35955

Summary:
Improve ThreadStatusSingleCompaction in two ways:
1. Use SYNC_POINT to ensure compaction won't happen
   before the test finishes its "Put Phase" instead of
   using sleep.
2. In Put Phase, it continues until we have sufficient
   number of L0 files.  Note that during the put phase,
   there won't be any compaction that consumes L0 files
   because of item 1.

Test Plan: ./db_test  --gtest_filter="*ThreadStatusSingleCompaction*"

Reviewers: sdong, igor, rven

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35727

Summary:
To understand the bug read t5943287 and check out the new test in column_family_test (ReadDroppedColumnFamily), iter 0.

RocksDB contract allowes you to read a drop column family as long as there is a live reference. However, since our iteration ignores dropped column families, AddLiveFiles() didn't mark files of a dropped column families as live. So we deleted them.

In this patch I no longer ignore dropped column families in the iteration. I think this behavior was confusing and it also led to this bug. Now if an iterator client wants to ignore dropped column families, he needs to do it explicitly.

Test Plan: Added a new unit test that is failing on master. Unit test succeeds now.

Reviewers: sdong, rven, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32535

Summary: It is no longer used by the implementation, so we should also remove it from the public API.

Test Plan: make check

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34971

Summary: Some suggestions for cleanup from Igor.

Test Plan: Regression tests.

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D35169

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:
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: 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:
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: 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: 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:
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

Test Plan: Run "make clean && make all check"

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

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D33627

Summary:
Prior to this change, "make check" would always waste a lot of
time relinking 60+ binaries. With this change, it does that
only when the generated file, util/build_version.cc, changes,
and that happens only when the date changes or when the
current git SHA changes.

This change makes some other improvements: before, there was no
rule to build a deleted util/build_version.cc. If it was somehow
removed, any attempt to link a program would fail.
There is no longer any need for the separate file,
build_tools/build_detect_version.  Its functionality is
now in the Makefile.

* Makefile (DEPFILES): Don't filter-out util/build_version.cc.
No need, and besides, removing that dependency was wrong.
(date, git_sha, gen_build_version): New helper variables.
(util/build_version.cc): New rule, to create this file
and update it only if it would contain new information.
* build_tools/build_detect_platform: Remove file.
* db/db_impl.cc: Now, print only date (not the time).
* util/build_version.h (rocksdb_build_compile_time): Remove
declaration.  No longer used.

Test Plan:
- Run "make check" twice, and note that the second time no linking is performed.
- Remove util/build_version.cc and ensure that any "make"
command regenerates it before doing anything else.
- Run this: strings librocksdb.a|grep _build_.
That prints output including the following:

  rocksdb_build_git_date:2015-02-19
  rocksdb_build_git_sha:2.8.fb-1792-g3cb6cc0

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D33591

Summary:
This is a diff for managed iterator. A managed iterator
is a wrapper around an iterator which saves the options for that
iterator as well as the current key/value so that the underlying iterator
and its associated memory can be released when it is aged out
automatically or on the request of the user. Will provide the automatic release as a follow-up diff.

Test Plan: Managed* tests in db_test and XF tests for managed iterator

Reviewers: igor, yhchiang, anthony, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D31401

Summary: Allow GetThreadList to reflect flush activity.

Test Plan:
Developed ThreadStatusFlush test and updated ThreadStatusMultiCompaction test.

./db_test  ./thread_list_test

Reviewers: sdong, rven, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D32871

Summary:
It would be good to assing background job their IDs. Two benefits:
1) makes LOGs more readable
2) I might use it in my EventLogger, which will try to make our LOG easier to read/query/visualize

Test Plan: ran rocksdb, read the LOG

Reviewers: sdong, rven, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D31617

Summary: For description of the bug, see comment in db_test. The fix is pretty straight forward.

Test Plan: added unit test. eventually we need better testing of FOF/POF process.

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D33081

Summary: Having a pointer for DB will be helpful to debug when GDB or working on a dump. If the client process doesn't have any thread actively working on RocksDB, it can be hard to find out.

Test Plan: make all check

Reviewers: rven, yhchiang, igor

Reviewed By: igor

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D33159

Summary:
This diff basically reverts D30249 and also adds a unit test that was failing before this patch.

I have no idea how I didn't catch this terrible bug when writing a diff, sorry about that :(

I think we should redesign our system of keeping track of and deleting files. This is already a second bug in this critical piece of code. I'll think of few ideas.

BTW this diff is also a regression when running lots of column families. I plan to revisit this separately.

Test Plan: added a unit test

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D33045

Summary:
When DestroyDB() finds a wal file in the DB directory, it assumes it is actually in WAL directory. This can lead to confusion, since it reports IO error when it tries to delete wal file from DB directory. For example: https://ci-builds.fb.com/job/rocksdb_clang_build/296/console

This change will fix our unit tests.

Test Plan: unit tests work

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32907

Summary:
Add a counter for collecting the wait time on db mutex.
Also add MutexWrapper and CondVarWrapper for measuring wait time.

Test Plan:
./db_test
export ROCKSDB_TESTS=MutexWaitStats
./db_test

verify stats output using db_bench
make clean
make release
./db_bench --statistics=1 --benchmarks=fillseq,readwhilewriting --num=10000 --threads=10

Sample output:
    rocksdb.db.mutex.wait.micros COUNT : 7546866

Reviewers: MarkCallaghan, rven, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32787

Summary: This adds a listener for compactions, and gives some useful statistics on each compaction pass.

Test Plan: Unit tests.

Reviewers: sdong, igor, rven, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D31641

Summary: log_dir_unsynced_ is a confusing name. Rename it to log_dir_synced_ and flip the value.

Test Plan: Run ./fault_injection_test

Reviewers: rven, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D32235

Summary:
1. If WAL directory is different from db directory. Sync the directory after creating a log file under it.
2. After creating an SST file, sync its parent directory instead of DB directory.
3. change the check of kResetDeleteUnsyncedFiles in fault_injection_test. Since we changed the behavior to sync log files' parent directory after first WAL sync, instead of creating, kResetDeleteUnsyncedFiles will not guarantee to show post sync updates.

Test Plan: make all check

Reviewers: yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D32067

Summary: We should not be calling InternalStats methods outside of the mutex.

Test Plan:
COMPILE_WITH_TSAN=1 m db_test && ROCKSDB_TESTS=CompactionTrigger ./db_test

failing before the diff, works now

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32127

Summary: Now we don't sync manifest file when initializing it, so DB cannot be safely reopened before the first mem table flush. Fix it by syncing it. This fixes fault_injection_test.

Test Plan: make all check

Reviewers: rven, yhchiang, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32001

Summary: GetLiveFilesMetaData() already adds a leading "/" in file name. No need to add one extra "/" in DBImpl::CheckConsistency()

Test Plan: make all check

Reviewers: yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D31779

Summary:
This patch remove the unnecessary Compaction::ReleaseInputs().

Compaction::ReleaseInputs() tries to unref its input_version
and column_family.  However, such unref is always done in
~Compaction(), and all current ReleaseInputs() calls are
right before the destructor.

Test Plan: ./db_test

Reviewers: igor

Reviewed By: igor

Subscribers: igor, rven, dhruba, sdong

Differential Revision: https://reviews.facebook.net/D31605

Summary: Allow GetThreadList() to indicate a thread is doing Compaction.

Test Plan:
export ROCKSDB_TESTS=ThreadStatus
./db_test

Reviewers: ljin, igor, sdong

Reviewed By: sdong

Subscribers: leveldb, dhruba, jonahcohen, rven

Differential Revision: https://reviews.facebook.net/D30105

Summary:
Add printing of stall time in DB Stats:

Sample outputs:

** DB Stats **
Uptime(secs): 53.2 total, 1.7 interval
Cumulative writes: 625940 writes, 625939 keys, 625940 batches, 1.0 writes per batch, 0.49 GB user ingest, stall micros: 50691070
Cumulative WAL: 625940 writes, 625939 syncs, 1.00 writes per sync, 0.49 GB written
Interval writes: 10859 writes, 10859 keys, 10859 batches, 1.0 writes per batch, 8.7 MB user ingest, stall micros: 1692319
Interval WAL: 10859 writes, 10859 syncs, 1.00 writes per sync, 0.01 MB written

Test Plan:
make all check
verify printing using db_bench

Reviewers: igor, yhchiang, rven, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D31239

Summary:
This patch changes concurrency guarantees around ColumnFamilySet::column_families_ and ColumnFamilySet::column_families_data_.

Before:
* When mutating: lock DB mutex and spin lock
* When reading: lock DB mutex OR spin lock

After:
* When mutating: lock DB mutex and be in write thread
* When reading: lock DB mutex or be in write thread

That way, we eliminate the spin lock that protects these hash maps and  simplify concurrency. That means we don't need to lock the spin lock during writing, since writing is mutually exclusive with column family create/drop (the only operations that mutate those hash maps).

With these new restrictions, I also needed to move column family create to the write thread (column family drop was already in the write thread).

Even though we don't need to lock the spin lock during write, impact on performance should be minimal -- the spin lock is almost never busy, so locking it is almost free.

This addresses task t5116919.

Test Plan:
make check

Stress test with lots and lots of column family drop and create:

   time ./db_stress --threads=30 --ops_per_thread=5000000 --max_key=5000 --column_families=200 --clear_column_family_one_in=100000 --verify_before_write=0  --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress/

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D30651

Summary: When trivial move commit is done, we log the summary of the input version instead of current. This is inconsistent with other log messages and confusing.

Test Plan: compiles

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D30939

Summary:
Since https://reviews.facebook.net/D16119, we ignore partial tailing writes. Because of that, we no longer need skip_log_error_on_recovery.

The documentation says "Skip log corruption error on recovery (If client is ok with losing most recent changes)", while the option actually ignores any corruption of the WAL (not only just the most recent changes). This is very dangerous and can lead to DB inconsistencies. This was originally set up to ignore partial tailing writes, which we now do automatically (after D16119). I have digged up old task t2416297 which confirms my findings.

Test Plan: There was actually no tests that verified correct behavior of skip_log_error_on_recovery.

Reviewers: yhchiang, rven, dhruba, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D30603