Summary:
In https://reviews.facebook.net/D56271, we fixed an issue where
we consider flush as compaction.  However, that makes us mistakenly
count FLUSH_WRITE_BYTES twice (one in flush_job and one in db_impl.)

This patch removes the one incremented in db_impl.

Test Plan: db_test

Reviewers: yiwu, andrewkr, IslamAbdelRahman, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57111

Summary: Correct a typo in a comment

Test Plan: No code change.

Reviewers: sdong, kradhakrishnan, IslamAbdelRahman

Reviewed By: kradhakrishnan, IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D55803

Summary:
Currently, when rocksdb tries to run manual compaction to refit data into a level,
there's a ReFitLevel() process that requires no bg work is currently running.
When RocksDB plans to ReFitLevel(), it will do the following:

 1. pause scheduling new bg work.
 2. wait until all bg work finished
 3. do the ReFitLevel()
 4. unpause scheduling new bg work.

However, as it pause scheduling new bg work at step one and waiting for all bg work
finished in step 2, RocksDB will stop flushing until all bg work is done (which
could take a long time.)

This patch fix this issue by changing the way ReFitLevel() pause the background work:

1. pause scheduling compaction.
2. wait until all bg work finished.
3. pause scheduling flush
4. do ReFitLevel()
5. unpause both flush and compaction.

The major difference is that.  We only pause scheduling compaction in step 1 and wait
for all bg work finished in step 2.  This prevent flush being blocked for a long time.
Although there's a very rare case that ReFitLevel() might be in starvation in step 2,
but it's less likely the case as flush typically finish very fast.

Test Plan: existing test.

Reviewers: anthony, IslamAbdelRahman, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D55029

Summary:
The call to

```
CaptureCurrentFileNumberInPendingOutputs()
```

should be before

```
versions_->NewFileNumber()
```
Right now we are not actually protecting the file from being deleted

Test Plan: make check

Reviewers: sdong, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D54645

Summary:
Add kSstFileTier to ReadTier, which allows Get and MultiGet to
read only directly from SST files and skip mem-tables.

    kSstFileTier = 0x2      // data in SST files.
                          // Note that this ReadTier currently only supports
                          // Get and MultiGet and does not support iterators.

Test Plan: add new test in db_test.

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: igor, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D53511

Summary:
Before this diff, there were duplicated constants to refer to properties (user-
facing API had strings and InternalStats had an enum). I noticed these were
inconsistent in terms of which constants are provided, names of constants, and
documentation of constants. Overall it seemed annoying/error-prone to maintain
these duplicated constants.

So, this diff gets rid of InternalStats's constants and replaces them with a map
keyed on the user-facing constant. The value in that map contains a function
pointer to get the property value, so we don't need to do string matching while
holding db->mutex_. This approach has a side benefit of making many small
handler functions rather than a giant switch-statement.

Test Plan: db_properties_test passes, running "make commit-prereq -j32"

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

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D53253

Summary:
If options.base_background_compactions is given, we try to schedule number of compactions not existing this number, only when L0 files increase to certain number, or pending compaction bytes more than certain threshold, we schedule compactions based on options.max_background_compactions.

The watermarks are calculated based on slowdown thresholds.

Test Plan:
Add new test cases in column_family_test.
Adding more unit tests.

Reviewers: IslamAbdelRahman, yhchiang, kradhakrishnan, rven, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba, yoshinorim

Differential Revision: https://reviews.facebook.net/D53409

Summary:
This is an initial diff for providing the ability to delete
files which are completely within a given range of keys.

Test Plan: DBCompactionTest.DeleteRange

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D52293

Summary: It's usually hard for users to set a value of options.delayed_write_rate. With this diff, after slowdown condition triggers, we greedily reduce write rate if estimated pending compaction bytes increase. If estimated compaction pending bytes drop, we increase the write rate.

Test Plan:
Add a unit test
Test with db_bench setting:
TEST_TMPDIR=/dev/shm/ ./db_bench --benchmarks=fillrandom -num=10000000 --soft_pending_compaction_bytes_limit=1000000000 --hard_pending_compaction_bytes_limit=3000000000 --delayed_write_rate=100000000

and make sure without the commit, write stop will happen, but with the commit, it will not happen.

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

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52131

Summary:
When there are waiting manual compactions, we need to signal
them after removing the current manual compaction from the deque.

Test Plan: ColumnFamilytTest.SameCFManualManualCommaction

Reviewers: anthony, IslamAbdelRahman, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, yoshinorim

Differential Revision: https://reviews.facebook.net/D52119

Running manual compactions in parallel with other automatic or manual compactions in restricted cases

Summary:
This diff provides a framework for doing manual
compactions in parallel with other compactions. We now have a deque of manual compactions. We also pass manual compactions as an argument from RunManualCompactions down to
BackgroundCompactions, so that RunManualCompactions can be reentrant.
Parallelism is controlled by the two routines
ConflictingManualCompaction to allow/disallow new parallel/manual
compactions based on already existing ManualCompactions. In this diff, by default manual compactions still have to run exclusive of other compactions. However, by setting the compaction option, exclusive_manual_compaction to false, it is possible to run other compactions in parallel with a manual compaction. However, we are still restricted to one manual compaction per column family at a time. All of these restrictions will be relaxed in future diffs.
I will be adding more tests later.

Test Plan: Rocksdb regression + new tests + valgrind

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

Reviewed By: sdong

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47973

Summary:
Currently, transactions can fail even if there is no actual write conflict.  This is due to relying on only the memtables to check for write-conflicts.  Users have to tune memtable settings to try to avoid this, but it's hard to figure out exactly how to tune these settings.

With this diff, TransactionDB will use both memtables and SST files to determine if there are any write conflicts.  This relies on the fact that BlockBasedTable stores sequence numbers for all writes that happen after any open snapshot.  Also, D50295 is needed to prevent SingleDelete from disappearing writes (the TODOs in this test code will be fixed once the other diff is approved and merged).

Note that Optimistic transactions will still rely on tuning memtable settings as we do not want to read from SST while on the write thread.  Also, memtable settings can still be used to reduce how often TransactionDB needs to read SST files.

Test Plan: unit tests, db bench

Reviewers: rven, yhchiang, kradhakrishnan, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb, yoshinorim

Differential Revision: https://reviews.facebook.net/D50475

Summary:
This patch fix a race condition in persisting options which will cause a crash when:

* Thread A obtain cf options and start to persist options based on that cf options.
* Thread B kicks in and finish DropColumnFamily and delete cf_handle.
* Thread A wakes up and tries to finish the persisting options and crashes.

Test Plan: Add a test in column_family_test that can reproduce the crash

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51717

Summary:
D51183 was reverted due to breaking the LITE build.

This diff is the same as D51183 but with a fix for the LITE BUILD(D51693)

Test Plan: run all unit tests

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51711

This reverts commit ec704aaf for it broke RocksDB LITE build.

Summary:
D50475 enables using SST files for transaction write-conflict checking.  In order for this to work, we need to make sure not to compact out SingleDeletes when there is an earlier transaction snapshot(D50295).  If there is a long-held snapshot, this could reduce the benefit of the SingleDelete optimization.

This diff allows Transactions to mark snapshots as being used for write-conflict checking.  Then, during compaction, we will be able to optimize SingleDeletes better in the future.

This diff adds a flag to SnapshotImpl which is used by Transactions.  This diff also passes the earliest write-conflict snapshot's sequence number to CompactionIterator.  This diff does not actually change Compaction (after this diff is pushed, D50295 will be able to use this information).

Test Plan: no behavior change, ran existing tests

Reviewers: rven, kradhakrishnan, yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51183

This reverts commit 2fa3ed51. It breaks RocksDB lite build

Summary:
This patch fix a race condition in persisting options which will cause a crash when:

* Thread A obtain cf options and start to persist options based on that cf options.
* Thread B kicks in and finish DropColumnFamily and delete cf_handle.
* Thread A wakes up and tries to finish the persisting options and crashes.

Test Plan: Add a test in column_family_test that can reproduce the crash

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51609

Summary:
Fixes T8781168.

Added a new function EnableAutoCompactions in db.h to be publicly
avialable.  This allows compaction to be re-enabled after disabling it via
SetOptions

Refactored code to set the dbptr earlier on in TransactionDB::Open and DB::Open
Temporarily disable auto_compaction in TransactionDB::Open until dbptr is set to
prevent race condition.

Test Plan:
Ran make all check

verified fix on myrocks side:
was able to reproduce the seg fault with
../tools/mysqltest.sh --mem --force rocksdb.drop_table

method was to manually sleep the thread after DB::Open but before TransactionDB ptr was
assigned in transaction_db_impl.cc:
  DB::Open(db_options, dbname, column_families_copy, handles, &db);
  clock_t goal = (60000 * 10) + clock();
  while (goal > clock());
  ...dbptr(aka rdb) gets assigned below

verified my changes fixed the issue.

Also added unit test 'ToggleAutoCompaction' in transaction_test.cc

Reviewers: hermanlee4, anthony

Reviewed By: anthony

Subscribers: alex, dhruba

Differential Revision: https://reviews.facebook.net/D51147

Summary: DBTest.DynamicCompactionOptions sometimes fails the assert but I can't repro it locally. Make it more deterministic and readable and see whether the problem is still there.

Test Plan: Run tht test and make sure it passes

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

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51309

Summary:
This patch allows rocksdb to persist options into a file on
DB::Open, SetOptions, and Create / Drop ColumnFamily.
Options files are created under the same directory as the rocksdb
instance.

In addition, this patch also adds a fail_if_missing_options_file in DBOptions
that makes any function call return non-ok status when it is not able to
persist options properly.

  // If true, then DB::Open / CreateColumnFamily / DropColumnFamily
  // / SetOptions will fail if options file is not detected or properly
  // persisted.
  //
  // DEFAULT: false
  bool fail_if_missing_options_file;

Options file names are formatted as OPTIONS-<number>, and RocksDB
will always keep the latest two options files.

Test Plan:
Add options_file_test.

options_test
column_family_test

Reviewers: igor, IslamAbdelRahman, sdong, anthony

Reviewed By: anthony

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48285

Summary:
This patch introduces utilities/memory, which currently includes
GetApproximateMemoryUsageByType that reports different types of
rocksdb memory usage given a list of input DBs.

The API also take care of the case where Cache could be shared
across multiple column families / multiple db instances.

Currently, it reports memory usage of memtable, table-readers
and cache.

Test Plan: utilities/memory/memory_test.cc

Reviewers: igor, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D49257

Summary:
This patch adds GetAggregatedIntProperty() that returns the aggregated
value from all CFs

Test Plan: Added a test in db_test

Reviewers: igor, sdong, anthony, IslamAbdelRahman, rven

Reviewed By: rven

Subscribers: rven, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D49497

Summary: As above.

Test Plan: USE_CLANG=1 make check -j

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48981

If log recycling is enabled, put old WAL files on a recycle queue instead of
deleting them.  When we need a new log file, take a recycled file off the
list if one is available.
Signed-off-by: NSage Weil <sage@redhat.com>

Summary: In MyRocks, it is sometimes important to get propeties only for the subset of the database. This diff implements the API in RocksDB.

Test Plan: ran the GetPropertiesOfTablesInRange

Reviewers: rven, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48651

Summary:
Add rocksdb.num-running-compactions and rocksdb.num-running-flushes
to GetIntProperty() that reports the number of currently running
compactions / flushes.

Test Plan: augmented existing tests in db_test

Reviewers: igor, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48693

Summary:
Separate a new class InternalIterator from class Iterator, when the look-up is done internally, which also means they operate on key with sequence ID and type.

This change will enable potential future optimizations but for now InternalIterator's functions are still the same as Iterator's.
At the same time, separate the cleanup function to a separate class and let both of InternalIterator and Iterator inherit from it.

Test Plan: Run all existing tests.

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

Reviewed By: rven

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48549

Summary:
Remove db_impl_debug from NDEBUG, but allow it in ROCKSDB_LITE
These functions by definition should not be included in NDEBUG and they are only used for testing
This is based on offline discussion with @yhchiang and @igor

Test Plan:
make static_lib
make check

Reviewers: igor, sdong, yhchiang

Reviewed By: yhchiang

Subscribers: igor, yhchiang, dhruba

Differential Revision: https://reviews.facebook.net/D48573

Summary:
Long time ago we add InternalDumpCommand to ldb_tool https://reviews.facebook.net/D11517
This command is using TEST_NewInternalIterator although it's not a test. This patch move TEST_NewInternalIterator outside of db_impl_debug.cc

Test Plan:
make check
make static_lib

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48561

Summary: It would be nice to have and access to table properties in compaction callbacks. In MyRocks project, it will make possible to update optimizer statistics online.

Test Plan: ran the unit test. Ran myrocks with the new way of collecting stats.

Reviewers: igor, rven, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48267

Summary:
Two changes:
1. remove *V2 filter stuff. we deprecated that a while ago
2. clarify what happens when user sets max_subcompactions to bigger than 1

Test Plan: none

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47871

Summary:
To support a new MongoDB capability, we need to make sure that we don't do any IO for a short period of time. For background, see:
* https://jira.mongodb.org/browse/SERVER-20704
* https://jira.mongodb.org/browse/SERVER-18899

To implement that, I add a new API calls PauseBackgroundWork() and ContinueBackgroundWork() which reuse the capability we already have in place for RefitLevel() function.

Test Plan: Added a new test in db_test. Made sure that test fails when PauseBackgroundWork() is commented out.

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47901

Summary:
This is an initial version of bulk load feature

This diff allow us to create sst files, and then bulk load them later, right now the restrictions for loading an sst file are
(1) Memtables are empty
(2) Added sst files have sequence number = 0, and existing values in database have sequence number = 0
(3) Added sst files values are not overlapping

Test Plan: unit testing

Reviewers: igor, ott, sdong

Reviewed By: sdong

Subscribers: leveldb, ott, dhruba

Differential Revision: https://reviews.facebook.net/D39081

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

Summary:
This diff is a collection of cleanups that were initially part of D43179.
Additionally it adds a unified way of defining key-value maps that use a
Comparator for sorting (this was previously implemented in four different
places).

Test Plan: make clean check all

Reviewers: rven, anthony, yhchiang, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45993

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: 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:
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