Summary:
This patch adds OptionsUtil::LoadOptionsFromFile() and
OptionsUtil::LoadLatestOptionsFromDB(), which allow developers
to construct DBOptions and ColumnFamilyOptions from a RocksDB
options file.  Note that most pointer-typed options such as
merge_operator will not be constructed.

With this API, developers no longer need to remember all the
options in order to reopen an existing rocksdb instance like
the following:

  DBOptions db_options;
  std::vector<std::string> cf_names;
  std::vector<ColumnFamilyOptions> cf_opts;

  // Load primitive-typed options from an existing DB
  OptionsUtil::LoadLatestOptionsFromDB(
      dbname, &db_options, &cf_names, &cf_opts);

  // Initialize necessary pointer-typed options
  cf_opts[0].merge_operator.reset(new MyMergeOperator());
  ...

  // Construct the vector of ColumnFamilyDescriptor
  std::vector<ColumnFamilyDescriptor> cf_descs;
  for (size_t i = 0; i < cf_opts.size(); ++i) {
    cf_descs.emplace_back(cf_names[i], cf_opts[i]);
  }

  // Open the DB
  DB* db = nullptr;
  std::vector<ColumnFamilyHandle*> cf_handles;
  auto s = DB::Open(db_options, dbname, cf_descs,
                    &handles, &db);

Test Plan:
Augment existing tests in column_family_test
options_test
db_test

Reviewers: igor, IslamAbdelRahman, sdong, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D49095

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:
Move some of the items in public API changes section to to new
features section.

Test Plan: no code change.

Reviewers: igor, sdong, anthony, IslamAbdelRahman

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D50229

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:
CreateLoggerFromOptions have some parameters like  db_log_dir and env, these parameters are redundant since they already exist in DBOptions

this patch remove the redundant parameters and expose CreateLoggerFromOptions to users

Test Plan: make check

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

Reviewed By: sdong

Subscribers: dhruba, hermanlee4

Differential Revision: https://reviews.facebook.net/D49713

Summary: DefaultCompactionFilterFactory is not used anymore after recent changes. Remove it.

Test Plan: Just run existing tests.

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

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48699

Summary: Pass column family ID through TablePropertiesCollectorFactory::CreateTablePropertiesCollector() so that users can identify which column family this file is for and handle it differently.

Test Plan: Add unit test scenarios in tests related to table properties collectors to verify the information passed in is correct.

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

Reviewed By: IslamAbdelRahman

Subscribers: yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48411

Summary: With this commit, we add a new format in manifest when adding a new file. Now path ID and need-compaction hint are first two customized fields.

Test Plan: Add a test case in version_edit_test to verify the encoding and decoding logic. Add a unit test in db_test to verify need compaction is persistent after DB restarting.

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

Reviewed By: igor

Subscribers: javigon, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48123

Summary: Add the column family ID to compaction filter context, so it is easier for compaction filter to apply different logic for different column families.

Test Plan: Add a unit test to verify the column family ID passed is correct.

Reviewers: rven, yhchiang, igor

Reviewed By: igor

Subscribers: yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48357

Summary: Change RocksDB version to 4.1

Test Plan: no code change.

Reviewers: sdong, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48387

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:
Since Andres' internship is over, I took over https://reviews.facebook.net/D42555 and rebased and simplified it a bit.

The behavior in this diff is a bit simpler than in D42555:
* only merge operators are passed through FilterMergeValue(). If fitler function returns true, the merge operator is ignored
* compaction filter is *not* called on: 1) results of merge operations and 2) base values that are getting merged with merge operands (the second case was also true in previous diff)

Do we also need a compaction filter to get called on merge results?

Test Plan: make && make check

Reviewers: lovro, tnovak, rven, yhchiang, sdong

Reviewed By: sdong

Subscribers: noetzli, kolmike, leveldb, dhruba, sdong

Differential Revision: https://reviews.facebook.net/D47847

Summary:
	Handle SST files with both ".sst" and ".ldb" suffix.
	This enables user to migrate from leveldb to rocksdb.

Test Plan:
        Added unit test with DB operating on SSTs with names schema.
        See db/dc_test.cc:SSTsWithLdbSuffixHandling for details

Reviewers: yhchiang, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48003

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: Release RocksDB 4.0.0

Test Plan: no test

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

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46515

Summary: Move line about pessimistic transactions to the correct place in the history file and no longer refer to it as 'experimental'

Test Plan: n/a

Reviewers: igor, sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46449

Summary:
In some cases, equality comparisons can be done more efficiently than three-way
comparisons. There are quite a few places in the code where we only care about
equality. This patch adds an Equal() method that defaults to using the
Compare() method.

Test Plan: make clean all check

Reviewers: rven, anthony, yhchiang, igor, sdong

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46233

Summary:
In the first implementation of BackupEngine, LATEST_BACKUP was the commit point. The backup became committed after the write to LATEST_BACKUP completed.

However, we can avoid the need for LATEST_BACKUP. Instead of write to LATEST_BACKUP, the commit point can be the rename from `meta/<backup_id>.tmp` to `meta/<backup_id>`. Once we see that there exists a file `meta/<backup_id>` (without tmp), we can assume that backup is valid.

In this diff, we still write out the file LATEST_BACKUP. We need to do this so that we can maintain backward compatibility. However, the new version doesn't depend on this file anymore. We get the latest backup by `ls`-ing `meta` directory.

This diff depends on D41925

Test Plan: Adjusted backupable_db_test to this new behavior

Reviewers: benj, yhchiang, sdong, AaronFeldman

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42069

Summary: Add ZSTD compression type. The same way as adding LZ4.

Test Plan: run all tests. Generate files in db_bench. Make sure reads succeed. But the SST files cannot be opened in older versions. Also some other adhoc tests.

Reviewers: rven, anthony, IslamAbdelRahman, kradhakrishnan, igor

Reviewed By: igor

Subscribers: MarkCallaghan, maykov, yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45747

Summary:
It was pointed out to me that the members of SubCompactionState
'earliest_snapshot', 'latest_snapshot' and 'visible_at_tip' are never
modified by the subcompactions, so they can stay as global varaibles
instead to make things simpler.

Test Plan: make all && make check

Reviewers: sdong, igor, noetzli, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45477

Summary:
This patch adds "rocksdb.aggregated-table-properties"
and "rocksdb.aggregated-table-properties-at-levelN", the former
returns the aggreated table properties of a column family,
while the later returns the aggregated table properties
of the specified level N.

Test Plan: Added tests in db_test

Reviewers: igor, sdong, IslamAbdelRahman, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45087

Summary:
Up until this point we had DbOptions.num_subcompactions, but
it is semantically more correct to call this max_subcompactions since
we will schedule *up to* DbOptions.max_subcompactions smaller compactions
at a time during a compaction job.

I also added a --subcompactions option to db_bench

Test Plan: make all   make check

Reviewers: sdong, igor, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45069

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:
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: 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:
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

Summary:
Subj. We really need this feature.

Previous diff D40899 has most of the changes to make this possible, this diff just adds the method.

Test Plan: `make check`, the new test fails without this diff; ran with ASAN, TSAN and valgrind.

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

Reviewed By: sdong

Subscribers: MarkCallaghan, maykov, hermanlee4, yoshinorim, tnovak, dhruba

Differential Revision: https://reviews.facebook.net/D40905

Summary:
Introduce DeleteScheduler that allow enforcing a rate limit on file deletion
Instead of deleting files immediately, files are moved to trash directory and deleted in a background thread that apply sleep penalty between deletes if needed.

I have updated PurgeObsoleteFiles and PurgeObsoleteWALFiles to use the delete_scheduler instead of env_->DeleteFile

Test Plan:
added delete_scheduler_test
existing unit tests

Reviewers: kradhakrishnan, anthony, rven, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43221

Summary: Polish HISTORY.md

Test Plan: no code change.

Reviewers: igor, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43527

Summary: Fix a typo and update HISTORY.md for NewCompactOnDeletionCollectorFactory().

Test Plan: no code change.

Reviewers: igor, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43521

Summary:
UpdateAccumulatedStats() is used to optimize compaction decision
esp. when the number of deletion entries are high, but this function
can slowdown DBOpen esp. in disk environment.

This patch adds DBOptions::skip_sats_update_on_db_open, which skips
UpdateAccumulatedStats() in DB::Open() time when it's set to true.

Test Plan: Add DBCompactionTest.SkipStatsUpdateTest

Reviewers: igor, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: tnovak, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42843

Summary:
Support RollbackToSavePoint() in WriteBatch and WriteBatchWithIndex.  Support for partial transaction rollback is needed for MyRocks.

An alternate implementation of Transaction::RollbackToSavePoint() exists in D40869.  However, the other implementation is messier because it is implemented outside of WriteBatch.  This implementation is much cleaner and also exposes a potentially useful feature to WriteBatch.

Test Plan: Added unit tests

Reviewers: IslamAbdelRahman, kradhakrishnan, maykov, yoshinorim, hermanlee4, spetrunia, sdong, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42723

Summary: Add new CheckFileExists method.  Considered changing the FileExists api but didn't want to break anyone's builds.

Test Plan: unit tests

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42003

Summary: It has been around for a while and it looks like it never found any uses in the wild. It's also complicating our compaction_job code quite a bit. We're deprecating it in 3.13, but will put it back in 3.14 if we actually find users that need this feature.

Test Plan: make check

Reviewers: noetzli, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42405

Summary:
Couple of changes here:
* NewBackupEngine() and NewReadOnlyBackupEngine() are now removed. They were deprecated since RocksDB 3.8. Changing these to new functions should be pretty straight-forward. As a followup, I'll fix all fbcode callsights
* Instead of initializing backup engine in the constructor, we initialize it in a separate function now. That way, we can catch all errors and return appropriate status code.
* We catch all errors during initializations and return them to the client properly.
* Added new tests to backupable_db_test, to make sure that we can't open BackupEngine when there are Env errors.
* Transitioned backupable_db_test to use BackupEngine rather than BackupableDB. From the two available APIs, judging by the current use-cases, it looks like BackupEngine API won. It's much more flexible since it doesn't require StackableDB.

Test Plan: Added a new unit test to backupable_db_test

Reviewers: yhchiang, sdong, AaronFeldman

Reviewed By: AaronFeldman

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41925

Summary: This option is guarding the feature implemented 2 and a half years ago: D8991. The feature was enabled by default back then and has been running without issues. There is no reason why any client would turn this feature off. I found no reference in fbcode.

Test Plan: none

Reviewers: sdong, yhchiang, anthony, dhruba

Reviewed By: dhruba

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42063

Summary:
In one of our recent meetings, we discussed deprecating features that are not being actively used. One of those features, at least within Facebook, is timeout_hint. The feature is really nicely implemented, but if nobody needs it, we should remove it from our code-base (until we get a valid use-case). Some arguments:
* Less code == better icache hit rate, smaller builds, simpler code
* The motivation for adding timeout_hint_us was to work-around RocksDB's stall issue. However, we're currently addressing the stall issue itself (see @sdong's recent work on stall write_rate), so we should never see sharp lock-ups in the future.
* Nobody is using the feature within Facebook's code-base. Googling for `timeout_hint_us` also doesn't yield any users.

Test Plan: make check

Reviewers: anthony, kradhakrishnan, sdong, yhchiang

Reviewed By: yhchiang

Subscribers: sdong, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41937

Summary: This change enables trivial move if all the input files are non onverlapping while doing Universal Compaction.

Test Plan: ./compaction_picker_test and db_test ran successfully with the new testcases.

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D40875