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: Added requirement that ComputeCompactionScore() be executed in mutex, since it's accessing being_compacted bool, which can be mutated by other threads. Also added more comments about thread safety of FileMetaData, since it was a bit confusing. However, it seems that FileMetaData doesn't have data races (except being_compacted)

Test Plan: Ran 100 ConvertCompactionStyle tests with thread sanitizer. On master -- some failures. With this patch -- none.

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32283

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

Test Plan: Compile. Run it.

Reviewers: yhchiang, dhruba, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D31479

Summary: Add an extra assert to make sure current version is included in VersionSet::AddLiveFiles().

Test Plan: make all check

Reviewers: yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, hermanlee4, leveldb

Differential Revision: https://reviews.facebook.net/D30819

Summary:
There are two versions of FindObsoleteFiles():
* full scan, which is executed every 6 hours (and it's terribly slow)
* no full scan, which is executed every time a background process finishes and iterator is deleted

This diff is optimizing the second case (no full scan). Here's what we do before the diff:
* Get the list of obsolete files (files with ref==0). Some files in obsolete_files set might actually be live.
* Get the list of live files to avoid deleting files that are live.
* Delete files that are in obsolete_files and not in live_files.

After this diff:
* The only files with ref==0 that are still live are files that have been part of move compaction. Don't include moved files in obsolete_files.
* Get the list of obsolete files (which exclude moved files).
* No need to get the list of live files, since all files in obsolete_files need to be deleted.

I'll post the benchmark results, but you can get the feel of it here: https://reviews.facebook.net/D30123

This depends on D30123.

P.S. We should do full scan only in failure scenarios, not every 6 hours. I'll do this in a follow-up diff.

Test Plan:
One new unit test. Made sure that unit test fails if we don't have a `if (!f->moved)` safeguard in ~Version.

make check

Big number of compactions and flushes:

  ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0  --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D30249

Summary:
Introduces a new class for managing write buffer memory across column
families.  We supplement ColumnFamilyOptions::write_buffer_size with
ColumnFamilyOptions::write_buffer, a shared pointer to a WriteBuffer
instance that enforces memory limits before flushing out to disk.

Test Plan: Added SharedWriteBuffer unit test to db_test.cc

Reviewers: sdong, rven, ljin, igor

Reviewed By: igor

Subscribers: tnovak, yhchiang, dhruba, xjin, MarkCallaghan, yoshinorim

Differential Revision: https://reviews.facebook.net/D22581

Summary:
Reported by bootcamper
This causes ldb tool to fail the assertion in ~ColumnFamilyData()

Test Plan:
./ldb --db=/tmp/test_db1 --create_if_missing put a1 b1
./ldb manifest_dump --path=/tmp/test_db1/MANIFEST-000001

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29517

Summary:
The very last reference happens in DBImpl::GetOptions()
I built with both DBImpl::GetOptions() and ColumnFamilyData::options() commented out

Test Plan: make all check

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29073

Summary:
Move NeedsCompaction() from VersionStorageInfo to CompactionPicker
to allow different compaction strategy to have their own way to
determine whether doing compaction is necessary.

When compaction style is set to kCompactionStyleNone, then
NeedsCompaction() will always return false.

Test Plan:
export ROCKSDB_TESTS=Compact
./db_test

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28719

Summary: So iOS size_t is 32-bit, so we need to static_cast<size_t> any uint64_t :(

Test Plan: TARGET_OS=IOS make static_lib

Reviewers: dhruba, ljin, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28743

Summary: I found that db_stress sometimes segfault on my machine. Fix the bug.

Test Plan: make all check. Run db_stress

Reviewers: ljin, yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D28803

Summary:
Fixed a bug in GetEstimatedActiveKeys which does not normalized
the sampled information correctly.

Add a test in version_builder_test.

Test Plan: version_builder_test

Reviewers: ljin, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28707

Summary:
We need to turn on -Wshorten-64-to-32 for mobile. See D1671432 (internal phabricator) for details.

This diff turns on the warning flag and fixes all the errors. There were also some interesting errors that I might call bugs, especially in plain table. Going forward, I think it makes sense to have this flag turned on and be very very careful when converting 64-bit to 32-bit variables.

Test Plan: compiles

Reviewers: ljin, rven, yhchiang, sdong

Reviewed By: yhchiang

Subscribers: bobbaldwin, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28689

Summary: Based on @sdong's feedback in the diff, we shouldn't keep db_mutex in CompactionJob's state. This diff removes db_mutex from CompactionJob state, by making next_file_number_ atomic. That way we only need to pass the lock to InstallCompactionResults() because of LogAndApply()

Test Plan: make check

Reviewers: ljin, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: sdong, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28491

Summary:
This diff adds three sets of APIs to RocksDB.

= GetColumnFamilyMetaData =
* This APIs allow users to obtain the current state of a RocksDB instance on one column family.
* See GetColumnFamilyMetaData in include/rocksdb/db.h

= EventListener =
* A virtual class that allows users to implement a set of
  call-back functions which will be called when specific
  events of a RocksDB instance happens.
* To register EventListener, simply insert an EventListener to ColumnFamilyOptions::listeners

= CompactFiles =
* CompactFiles API inputs a set of file numbers and an output level, and RocksDB
  will try to compact those files into the specified level.

= Example =
* Example code can be found in example/compact_files_example.cc, which implements
  a simple external compactor using EventListener, GetColumnFamilyMetaData, and
  CompactFiles API.

Test Plan:
listener_test
compactor_test
example/compact_files_example
export ROCKSDB_TESTS=CompactFiles
db_test
export ROCKSDB_TESTS=MetaData
db_test

Reviewers: ljin, igor, rven, sdong

Reviewed By: sdong

Subscribers: MarkCallaghan, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D24705

Summary: It turns out that -Wshadow has different rules for gcc than clang. Previous commit fixed clang. This commits fixes the rest of the warnings for gcc.

Test Plan: compiles

Reviewers: ljin, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28131

Summary: Apply InfoLogLevel to the logs in db/version_set.cc

Test Plan: make

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27879

Summary: Enforce the accessier naming convention in functions in version_set.h

Test Plan: make all check

Reviewers: ljin, yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D28143

Summary: Move all the logic of VersionBuilder to a separate .cc file

Test Plan: make all check

Reviewers: ljin, yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D28083

Summary: BaseReferencedVersionBuilder now unreference version before destructing VersionBuilder, which is wrong. Fix it.

Test Plan:
make all check
valgrind test to tests that used to fail

Reviewers: igor, yhchiang, rven, ljin

Reviewed By: ljin

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D28101

Summary:
...and fix all the errors :)

Jim suggested turning on -Wshadow because it helped him fix number of critical bugs in fbcode. I think it's a good idea to be -Wshadow clean.

Test Plan: compiles

Reviewers: yhchiang, rven, sdong, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27711

Summary:
Rename Version::Builder to VersionBuilder and expose its definition to a header.
Make VerisonBuilder not reference Version or ColumnFamilyData, only working with VersionStorageInfo.
Add version_builder_test which has a simple test.

Test Plan: make all check

Reviewers: rven, yhchiang, igor, ljin

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D27969

Summary:
Make compaction picker easier to test.
The basic idea is to separate a minimum subcomponent of Version to VersionStorageInfo, which just responsible to LSM tree. A stub VersionStorageInfo can then be easily created and passed into compaction picker so that we can check the outputs.

It now passes most tests. Still two things need to be done:
(1) deal with the FIFO compaction's file size.
(2) write an example test to make sure the interface can do the job.

Add a compaction_picker_test to make sure compaction picker codes can be easily unit tested.

Test Plan:
Pass all unit tests and compaction_picker_test

Reviewers: yhchiang, rven, igor, ljin

Reviewed By: ljin

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D27639

Summary:
This diff has two fixes.

1. Fix the bug where compaction does not fail when RocksDB can't create a new file.
2. When NewWritableFiles() fails in OpenCompactionOutputFiles(), previously such fail-to-created file will be still be included as a compaction output.  This patch also fixes this bug.
3. Allow VersionEdit::EncodeTo() to return Status and add basic check.

Test Plan:
./version_edit_test
export ROCKSDB_TESTS=FileCreationRandomFailure
./db_test

Reviewers: ljin, sdong, nkg-, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D25581

Summary: No need to expose them in .h

Test Plan: make release

Reviewers: igor, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27645

Summary: as title

Test Plan:
make release
will run full test on all stacked diffs before committing

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27591

Summary:
We have several different types of data structures for file information.
FileLevel is kinda of confusing since it only contains file range and
fd. Rename it to LevelFilesBrief to make it clear.
Unfriend CompactedDBImpl as a by product

Test Plan:
make release / make all
will run full test with all stacked diffs

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27585

Summary: as title

Test Plan:
make release
I will run make all check for all stacked diffs before commit

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27573

Summary: as title

Test Plan: running make all check

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27549

Summary:
Make inplace_update_support and inplace_update_num_locks dynamic.
inplace_callback becomes immutable
We are almost free of references to cfd->options() in db_impl

Test Plan: unit test

Reviewers: igor, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D25293

Summary: as title

Test Plan: unit test

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D25347

Summary:
This diff speeds up DB::Open() and Version creation by limiting the number of FileMetaData initialization. The behavior of Version::UpdateAccumulatedStats() is changed as follows:

* It only initializes the first 20 uninitialized FileMetaData from file.  This guarantees the size of the latest 20 files will always be compensated when they have any deletion entries.  Previously it may initialize all FileMetaData by loading all files at DB::Open().
* In case none the first 20 files has any data entry, UpdateAccumulatedStats() will initialize the FileMetaData of the oldest file.

Test Plan: db_test

Reviewers: igor, sdong, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D24255

Summary:
make compaction related options changeable. Most of changes are tedious,
following the same convention: grabs MutableCFOptions at the beginning
of compaction under mutex, then pass it throughout the job and register
it in SuperVersion at the end.

Test Plan: make all check

Reviewers: igor, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D23349

Fix for:

[db/version_set.cc:1219]: (style) Unsigned variable 'last_file'
 can't be negative so it is unnecessary to test it.
[db/version_set.cc:1234]: (style) Unsigned variable 'first_file'
 can't be negative so it is unnecessary to test it.
Signed-off-by: NDanny Al-Gaaf <danny.al-gaaf@bisect.de>

Use empty() since it should be prefered as it has, following
the standard, a constant time complexity regardless of the
containter type. The same is not guaranteed for size().

Fix for:
[db/version_set.cc:2250]: (performance) Possible inefficient
 checking for 'column_families_not_found' emptiness.
Signed-off-by: NDanny Al-Gaaf <danny.al-gaaf@bisect.de>

Summary:
Intead of passing callback function pointer and its arg on Table::Get()
interface, passing GetContext. This makes the interface cleaner and
possible better perf. Also adding a fast pass for SaveValue()

Test Plan: make all check

Reviewers: igor, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D24057

Summary:
Add a CompactedDBImpl that will enabled when calling OpenForReadOnly()
and the DB only has one level (>0) of files. As a performan comparison,
CuckooTable performs 2.1M/s with CompactedDBImpl vs. 1.78M/s with
ReadOnlyDBImpl.

Test Plan: db_bench

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D23553

Summary: as title

Test Plan:
make all check
I will think a way to set up stress test for this

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D23055

Summary: As we discussed offline

Test Plan: compiles

Reviewers: yhchiang, sdong, ljin, dhruba

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D22989