Summary:
This patch fixes #7460559. It introduces SingleDelete as a new database
operation. This operation can be used to delete keys that were never
overwritten (no put following another put of the same key). If an overwritten
key is single deleted the behavior is undefined. Single deletion of a
non-existent key has no effect but multiple consecutive single deletions are
not allowed (see limitations).

In contrast to the conventional Delete() operation, the deletion entry is
removed along with the value when the two are lined up in a compaction. Note:
The semantics are similar to @igor's prototype that allowed to have this
behavior on the granularity of a column family (
https://reviews.facebook.net/D42093 ). This new patch, however, is more
aggressive when it comes to removing tombstones: It removes the SingleDelete
together with the value whenever there is no snapshot between them while the
older patch only did this when the sequence number of the deletion was older
than the earliest snapshot.

Most of the complex additions are in the Compaction Iterator, all other changes
should be relatively straightforward. The patch also includes basic support for
single deletions in db_stress and db_bench.

Limitations:
- Not compatible with cuckoo hash tables
- Single deletions cannot be used in combination with merges and normal
  deletions on the same key (other keys are not affected by this)
- Consecutive single deletions are currently not allowed (and older version of
  this patch supported this so it could be resurrected if needed)

Test Plan: make all check

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

Reviewed By: igor

Subscribers: maykov, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43179

fixed typos in comments of options.h

Summary:
Some users have observed errors in the log file when
the log file or sst file is already deleted.

Test Plan:
Make sure that the errors do not appear for already deleted
files.

Reviewers: sdong

Reviewed By: sdong

Subscribers: anthony, kradhakrishnan, yhchiang, rven, igor, IslamAbdelRahman, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47115

Summary: The diff modifies the condition checked to determine the bottommost level during compaction. Previously, absence of files in higher levels alone was used as the condition. Now, the function additionally evaluates if the higher levels have files which have non-overlapping key ranges, then the level can be safely considered as the bottommost level.

Test Plan: Unit test cases added and passing. However, unit tests of universal compaction are failing as a result of the changes made in this diff. Need to understand why that is happening.

Reviewers: igor

Subscribers: dhruba, sdong, lgalanis, meyering

Differential Revision: https://reviews.facebook.net/D46473

Summary: Now DB::Open() flushes info log before printing DB pointer, so it may not show up if no activity after DB open. Move log flushing from after printing options to printing DB pointer.

Test Plan: make commit-prereq

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

Reviewed By: rven

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D47121

Summary:
There were two minor issues with 9566342d:
- The install command was doing `cmake` instead of `cmake .`
- `LIBRARY_PATH` was not set
Fix both issues.

Test Plan: Run tests on Travis: https://travis-ci.org/facebook/rocksdb/jobs/80699627 (bloom_test works now).

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47103

Summary: Fix two constants in WaitFor() that multiply a value with 000 instead of 1000.

Test Plan: make clean all check

Reviewers: rven, anthony, yhchiang, aekmekji, sdong, MarkCallaghan, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47091

Summary:
When running `make rocksdbjava V=1`, it currently does
not print out the original command but something odd instead:

    mkdir -p jl/db

This patch tries to fix this issue.

Test Plan: make rocksdbjava V=1

Reviewers: igor, sdong, IslamAbdelRahman, meyering

Reviewed By: meyering

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47061

Summary: Change the log level of DB start-up log from Warn to Header.

Test Plan: db_bench and observe the LOG header

Reviewers: igor, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47067

Summary:
Unfortunately it is not easily possible to install gflags as a package on
Travis. Change the Travis script to download and build gflags. This patch
avoids "sudo make install" so that we can continue to use Travis'
container-based infrastructure.

Test Plan: Run tests on Travis.

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47037

Summary: This will unblock the corresponding change in MyRocks

Test Plan: ran rocksdb.write_sync test

Reviewers: sdong, kolmike

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46911

Summary: Missed one file in the previous commit

Test Plan: compiles

Reviewers: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47055

Summary: If we skip a test, we shouldn't mark `make check` as failure. This fixes travis CI test.

Test Plan: Travis CI

Reviewers: noetzli, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47031

Summary:
Although compaction time is recorded in the statistics,
it is helpful to include this value in the log output corresponding
to the end of compaction.

Test Plan: make all && make check

Reviewers: yhchiang, sdong, igor, noetzli, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D47007

Summary:
In case of huge db backup infromation about progress of downloading would help.
New callback parameter in CreateNewBackup() function will trigger whenever a some amount of data downloaded.
Task: 8057631

Test Plan:
ProgressCallbackDuringBackup test that cover new functionality added to BackupableDBTest tests.
other test succeed as well.

Reviewers: Guenena, benj, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46575

Summary: This should let us pass tests on OS X.

Test Plan: none yet

Reviewers: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46989

Summary:
RocksDB options can be dumped to the log file, and
up to this point the max_subcompactions option was not included
in this dump. This fixes that.

Test Plan: makek all && make check

Reviewers: MarkCallaghan, igor, noetzli, anthony, yhchiang, sdong

Reviewed By: yhchiang, sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46971

Summary: There was a merge issue with SleepingBackgroundTask

Test Plan: compiles now

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46977

Summary:
This patch finally fixes the ColumnFamilyTest.ReadDroppedColumnFamily test. The test has been failing very sporadically and it was hard to repro. However, I managed to write a new tests that reproes the failure deterministically.

Here's what happens:
1. We start the flush for the column family
2. We check if the column family was dropped here: https://github.com/facebook/rocksdb/blob/a3fc49bfddcdb1ff29409aacd06c04df56c7a1d7/db/flush_job.cc#L149
3. This check goes through, ends up in InstallMemtableFlushResults() and it goes into LogAndApply()
4. At about this time, we start dropping the column family. Dropping the column family process gets to LogAndApply() at about the same time as LogAndApply() from flush process
5. Drop column family goes through LogAndApply() first, marking the column family as dropped.
6. Flush process gets woken up and gets a chance to write to the MANIFEST. However, this is where it gets stuck: https://github.com/facebook/rocksdb/blob/a3fc49bfddcdb1ff29409aacd06c04df56c7a1d7/db/version_set.cc#L1975
7. We see that the column family was dropped, so there is no need to write to the MANIFEST. We return OK.
8. Flush gets OK back from LogAndApply() and it deletes the memtable, thinking that the data is now safely persisted to sst file.

The fix is pretty simple. Instead of OK, we return ShutdownInProgress. This is not really true, but we have been using this status code to also mean "this operation was canceled because the column family has been dropped".

The fix is only one LOC. All other code is related to tests. I added a new test that reproes the failure. I also moved SleepingBackgroundTask to util/testutil.h (because I needed it in column_family_test for my new test). There's plenty of other places where we reimplement SleepingBackgroundTask, but I'll address that in a separate commit.

Test Plan:
1. new test
2. make check
3. Make sure the ColumnFamilyTest.ReadDroppedColumnFamily doesn't fail on Travis: https://travis-ci.org/facebook/rocksdb/jobs/79952386

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

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46773

Summary: Timeout needs to be set for command and job for it to work.

Test Plan: Manual

Reviewers: sdong igor

CC: levledb@

Task ID: #6968635

Blame Rev:

Summary:
The default behavior for atomic operations is sequentially consistent ordering
which is not needed for simple counters (see:
http://en.cppreference.com/w/cpp/atomic/memory_order). Change the memory order
to std::memory_order_relaxed for better performance.

Test Plan: make clean all check

Reviewers: rven, anthony, yhchiang, aekmekji, sdong, MarkCallaghan, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46953

Summary:
There are some use cases in MyRocks to compare two slices
and to return the first byte where they differ. It may be
useful to add it as a RocksDB Slice function.

Test Plan: db_test

Reviewers: sdong, rven, igor

Reviewed By: igor

Subscribers: jkedgar, dhruba

Differential Revision: https://reviews.facebook.net/D46935

Fix `integer overflow in expression' error

Fix printf format for size_t

DBImpl::FindObsoleteFiles() shouldn't release mutex between getting min_pending_output and scanning files

Summary:
Releasing mutex between getting min_pending_output and scanning files may cause min_pending_output to be max but some non-final files are found in file scanning, ending up with deleting wrong files.
As a recent regression, mutex can be released while waiting for log sync. We move it to after file scanning.

Test Plan: Run all existing tests. Don't think it is easy to write a unit test. Maybe we should find a way to assert lock not released so that we can have some test verification for similar cases.

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

Reviewed By: rven

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D46899

Summary:
Valgrind is complaining because we are using hard_rate_limit (when serializing the options) without being initialized
http://our.intern.facebook.com/intern/sandcastle/3962140295/77533971/

Test Plan: run the test under valgrind

Reviewers: kradhakrishnan, yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46929

Summary:
Skip these tests under ROCKSDB_LITE

compaction_job_stats_test
corruption_test
transactions/transaction_test

Test Plan: compile using ROCKSDB_LITE

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46923

Summary:
Travis is failing due to missing gflags
(https://travis-ci.org/facebook/rocksdb/jobs/80307921). Adding libgflags-dev
should help.

Test Plan: Run tests on Travis.

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

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46905

Summary: Add an option to stop writes if compaction lefts behind. If estimated pending compaction bytes is more than threshold specified by options.hard_pending_compaction_bytes_liimt, writes will stop until compactions are cleared to under the threshold.

Test Plan: Add unit test DBTest.HardLimit

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

Reviewed By: igor

Subscribers: MarkCallaghan, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45999

Summary: Fix compaction_job_stats under ROCKSDB_LITE

Test Plan: compile using ROCKSDB_LITE

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46887

Refactor to support file_reader_writer on Windows.

Summary: Command level timeouts are not working. Moving it to step level.

Test Plan: Manual testing sending commands

Reviewers: sdong igor

CC: leveldb@

Task ID: #6968635

Blame Rev:

Summary:
Commit c67d2068 did not fix all test conditions
which use Arena::MemoryAllocatedBytes() (see Travis failure
https://travis-ci.org/facebook/rocksdb/jobs/79957700). The assumption of that
commit was that aligned allocations do not call Arena::AllocateNewBlock(), so
malloc_usable_block_size() would not be used for Arena::MemoryAllocatedBytes().
However, there is a code path where Arena::AllocateAligned() calls
AllocateFallback() which in turn calls Arena::AllocateNewBlock(), so
Arena::MemoryAllocatedBytes() may return a greater value than expected even for
aligned requests.

Test Plan: make arena_test && ./arena_test

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

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46869

Summary:
Although there are currently counters to keep track of the
stall caused by having too many L0 files, there is no distinction as
to whether when that stall occurs either (A) L0-L1 compaction is taking
place to try and mitigate it, or (B) no L0-L1 compaction has been scheduled
at the moment. This diff adds a counter for (A) so that the nature of L0
stalls can be better understood.

Test Plan: make all && make check

Reviewers: sdong, igor, anthony, noetzli, yhchiang

Reviewed By: yhchiang

Subscribers: MarkCallaghan, dhruba

Differential Revision: https://reviews.facebook.net/D46749

Summary: Transaction::RollbackToSavePoint() will now release any locks that were taken since the previous SavePoint.  To do this cleanly, I moved tracked_keys_ management into TransactionBase.

Test Plan: New Transaction test.

Reviewers: igor, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, spetrunia, leveldb

Differential Revision: https://reviews.facebook.net/D46761

 Fix compilation issues on GCC/CLANG
 Address Windows Release test build issues due to Sync

Summary: Fixed
- Added timeouts for crash tests. They take around 9hrs.
- Added oncall so we can get notifications for timeout etc.
- Fixed a bug in the valgrind script
- Cosmetic fix

Test Plan: Manual run

Reviewers: sdong igor

CC: leveldb@

Task ID: #6968635

Blame Rev: