Summary:
The recently reverted behavior changes were released to at least one
place internally, so we should mention the reverts in release notes.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7617

Reviewed By: akankshamahajan15

Differential Revision: D24654343

Pulled By: ajkr

fbshipit-source-id: eb64b2797d8508cd95a2dc2698122c1be29ce817

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/7615

Reviewed By: riversand963

Differential Revision: D24637054

Pulled By: ajkr

fbshipit-source-id: 7da20d44289eaa2387af4edf8c3c48057425cc1c

Summary:
Add 6.14 to check_format_compatible.sh

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7613

Test Plan: ./tools/check_format_compatible.sh

Reviewed By: riversand963

Differential Revision: D24628535

Pulled By: akankshamahajan15

fbshipit-source-id: a8bf1d5505a1fcc8a5bedc5ff4fdf33a22c3f2e6

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/7612

Reviewed By: zhichao-cao

Differential Revision: D24627054

Pulled By: riversand963

fbshipit-source-id: 451b4da742e3e84c7442bc7cc4959d39089b89d0

Summary:
This is a PR generated **semi-automatically** by an internal tool to remove unused includes and `using` statements.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7604

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D24579392

Pulled By: riversand963

fbshipit-source-id: c4bfa6c6b08da1de186690d37eb73d8fff45aecd

Summary:
update GetColumnFamilyMetaData() to getColumnFamilyMetaData()

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7606

Reviewed By: zhichao-cao

Differential Revision: D24610298

Pulled By: cheng-chang

fbshipit-source-id: d24f9b65478da1456f50747637dc95688af874de

Summary:
CreateFileChecksumGenerator may uses requested_checksum_func_name in generator context to decide which generator will be used. GenerateOneFileChecksum has not being updated to use it, which will always get the generator when the name is empty. Fix it.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7586

Test Plan: make check

Reviewed By: riversand963

Differential Revision: D24491989

Pulled By: zhichao-cao

fbshipit-source-id: d9fdfdd431240f0a9a2e781ddbd48a7d6c609aad

Summary:
Fix a few typos and avoid a potential nullptr dereference.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7592

Reviewed By: zhichao-cao

Differential Revision: D24582111

Pulled By: riversand963

fbshipit-source-id: 51e9260e8cad1fcdedd310c889f0faeec6efd937

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/7593

Reviewed By: zhichao-cao

Differential Revision: D24576218

Pulled By: riversand963

fbshipit-source-id: a3d77191362ca696ae9df643f97f4ab5b7ecff12

Summary:
Because `Close()` have called in `Destroy()`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7594

Reviewed By: zhichao-cao

Differential Revision: D24576407

Pulled By: riversand963

fbshipit-source-id: eba70d73375fd47dd78ca64c6a1fab3628448276

Summary:
Fixes Issue https://github.com/facebook/rocksdb/issues/7497

When allow_data_in_errors db_options is set, log error key details in `ParseInternalKey()`

Have fixed most of the calls. Have few TODOs still pending - because have to make more deeper changes to pass in the allow_data_in_errors flag. Will do those in a separate PR later.

Tests:
- make check
- some of the existing tests that exercise the "internal key too small" condition are: dbformat_test, cuckoo_table_builder_test
- some of the existing tests that exercise the corrupted key path are: corruption_test, merge_helper_test, compaction_iterator_test

Example of new status returns:
- Key too small - `Corrupted Key: Internal Key too small. Size=5`
- Corrupt key with allow_data_in_errors option set to false: `Corrupted Key: '<redacted>' seq:3, type:3`
- Corrupt key with allow_data_in_errors option set to true: `Corrupted Key: '61' seq:3, type:3`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7515

Reviewed By: ajkr

Differential Revision: D24240264

Pulled By: ramvadiv

fbshipit-source-id: bc48f5d4475ac19d7713e16df37505b31aac42e7

Summary:
A user who extended `Logger` recently pointed out it is unusual to
require they implement the two-argument `Logv()` overload when they've
already implemented the three-argument `Logv()` overload. I agree with
that and think we can fix it by only calling the two-argument overload
from the default implementation of the three-argument overload. Then
when the three-argument overload is overridden, RocksDB would not
rely on the two-argument overload. Only `Logger::LogHeader()` needed
adjustment to achieve this.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7605

Reviewed By: riversand963

Differential Revision: D24584749

Pulled By: ajkr

fbshipit-source-id: 9aabe040ac761c4c0dbebc4be046967403ecaf21

Summary:
My previous change to use lib2to3 to migrate clang-format-diff.py
for Python 2 only works if there's nothing to reformat. Instead, give
instructions to download to REPO_ROOT.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7603

Test Plan: Try the instructions on a fresh CentOS 8 devserver

Reviewed By: riversand963

Differential Revision: D24569608

Pulled By: pdillinger

fbshipit-source-id: 1410ba163e016b226e883dec93fae3df9ed0eab2

Summary:
This PR does a few things:

1.  The MockFileSystem class was split out from the MockEnv.  This change would theoretically allow a MockFileSystem to be used by other Environments as well (if we created a means of constructing one).  The MockFileSystem implements a FileSystem in its entirety and does not rely on any Wrapper implementation.

2.  Make the RocksDB test suite work when MOCK_ENV=1 and ENCRYPTED_ENV=1 are set.  To accomplish this, a few things were needed:
- The tests that tried to use the "wrong" environment (Env::Default() instead of env_) were updated
- The MockFileSystem was changed to support the features it was missing or mishandled (such as recursively deleting files in a directory or supporting renaming of a directory).

3.  Updated the test framework to have a ROCKSDB_GTEST_SKIP macro.  This can be used to flag tests that are skipped.  Currently, this defaults to doing nothing (marks the test as SUCCESS) but will mark the tests as SKIPPED when RocksDB is upgraded to a version of gtest that supports this (gtest-1.10).

I have run a full "make check" with MEM_ENV, ENCRYPTED_ENV,  both, and neither under both MacOS and RedHat.  A few tests were disabled/skipped for the MEM/ENCRYPTED cases.  The error_handler_fs_test fails/hangs for MEM_ENV (presumably a timing problem) and I will introduce another PR/issue to track that problem.  (I will also push a change to disable those tests soon).  There is one more test in DBTest2 that also fails which I need to investigate or skip before this PR is merged.

Theoretically, this PR should also allow the test suite to run against an Env loaded from the registry, though I do not have one to try it with currently.

Finally, once this is accepted, it would be nice if there was a CircleCI job to run these tests on a checkin so this effort does not become stale.  I do not know how to do that, so if someone could write that job, it would be appreciated :)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7566

Reviewed By: zhichao-cao

Differential Revision: D24408980

Pulled By: jay-zhuang

fbshipit-source-id: 911b1554a4d0da06fd51feca0c090a4abdcb4a5f

Summary:
Currently, the following interleaving of events can lead to SuperVersion containing both immutable memtables as well as the resulting L0. This can cause Get to return incorrect result if there are merge operands. This may also affect other operations such as single deletes.

```
  time  main_thr  bg_flush_thr  bg_compact_thr  compact_thr  set_opts_thr
0  |                                                         WriteManifest:0
1  |                                           issue compact
2  |                                 wait
3  |   Merge(counter)
4  |   issue flush
5  |                   wait
6  |                                                         WriteManifest:1
7  |                                 wake up
8  |                                 write manifest
9  |                  wake up
10 |  Get(counter)
11 |                  remove imm
   V
```

The reason behind is that: one bg flush thread's installing new `Version` can be batched and performed by another thread that is the "leader" MANIFEST writer. This bg thread removes the memtables from current super version only after `LogAndApply` returns. After the leader MANIFEST writer signals (releasing mutex) this bg flush thread, it is possible that another thread sees this cf with both memtables (whose data have been flushed to the newest L0) and the L0 before this bg flush thread removes the memtables.

To address this issue, each bg flush thread can pass a callback function to `LogAndApply`. The callback is responsible for removing the memtables. Therefore, the leader MANIFEST writer can call this callback and remove the memtables before releasing the mutex.

Test plan (devserver)
```
$make merge_test
$./merge_test --gtest_filter=MergeTest.MergeWithCompactionAndFlush
$make check
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6069

Reviewed By: cheng-chang

Differential Revision: D18790894

Pulled By: riversand963

fbshipit-source-id: e41bd600c0448b4f4b2deb3f7677f95e3076b4ed

Summary:
Similarly to how https://github.com/facebook/rocksdb/issues/7345
integrated blob file writing into the flush process,
the patch adds support for writing blob files to the compaction logic.
Namely, if `enable_blob_files` is set, large values encountered during
compaction are extracted to blob files and replaced with blob indexes.
The resulting blob files are then logged to the MANIFEST as part of the
compaction job's `VersionEdit` and added to the `Version` alongside any
table files written by the compaction. Any errors during blob file building fail
the compaction job.

There will be a separate follow-up patch to perform blob garbage collection
during compactions.

In addition, the patch continues to chip away at the mess around computing
various compaction related statistics by eliminating some code duplication
and by making the `num_output_files` and `bytes_written` stats more consistent
for flushes, compactions, and recovery.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7573

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D24404696

Pulled By: ltamasi

fbshipit-source-id: 21216af3a172ad3ce8f85d11cd30923784ae426c

Summary:
This is intended as the first commit toward a near-optimal alternative to static Bloom filters for SSTs. Stephan Walzer and I have agreed upon the name "Ribbon" for a PHSF based on his linear system construction in "Efficient Gauss Elimination for Near-Quadratic Matrices with One Short Random Block per Row, with Applications" ("SGauss") and my much faster "on the fly" algorithm for gaussian elimination (or for this linear system, "banding"), which can be faster than peeling while also more compact and flexible. See util/ribbon_alg.h for more detailed introduction and background. RIBBON = Rapid Incremental Boolean Banding ON-the-fly

This commit just adds generic (templatized) core algorithms and a basic unit test showing some features, including the ability to construct structures within 2.5% space overhead vs. information theoretic lower bound. (Compare to cache-local Bloom filter's ~50% space overhead -> ~30% reduction anticipated.) This commit does not include the storage scheme necessary to make queries fast, especially for filter queries, nor fractional "result bits", but there is some description already and those implementations will come soon. Nor does this commit add FilterPolicy support, for use in SST files, but that will also come soon.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7491

Reviewed By: jay-zhuang

Differential Revision: D24517954

Pulled By: pdillinger

fbshipit-source-id: 0119ee597e250d7e0edd38ada2ba50d755606fa7

Summary:
Add a threshold timestamp, full_history_ts_low_ of type `std::string*` to
`CompactionIterator`, so that RocksDB can also perform garbage collection during
compaction.
* If full_history_ts_low_ is nullptr, then compaction iterator does not perform
  GC, preserving all timestamp history for all keys. Compaction iterator will
treat user key with different timestamps as different user keys.
* If full_history_ts_low_ is not nullptr, then compaction iterator performs
  GC. GC will look at keys older than `*full_history_ts_low_` and determine their
  eligibility based on factors including snapshots.

Current rules of GC:
 * If an internal key is in the same snapshot as a previous counterpart
    with the same user key, and this key is eligible for GC, and the key is
    not single-delete or merge operand, then this key can be dropped. Note
    that the previous internal key cannot be a merge operand either.
 * If a tombstone is the most recent one in the earliest snapshot and it
    is eligible for GC, and keyNotExistsBeyondLevel() is true, then this
    tombstone can be dropped.
 * If a tombstone is the most recent one in a snapshot and it is eligible
    for GC, and the compaction is at bottommost level, then all other older
    internal keys of the same user key must also be eligible for GC, thus
    can be dropped
* Single-delete, delete-range and merge are not currently supported.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7556

Test Plan: make check

Reviewed By: ltamasi

Differential Revision: D24507728

Pulled By: riversand963

fbshipit-source-id: 3c09c7301f41eed76dfcf4d1527e68cf6e0a8bb3

Summary:
This PR makes it able to `LogAndApply` `VersionEdit`s related to WALs, and also be able to `Recover` from MANIFEST with WAL related `VersionEdit`s.

The `VersionEdit`s related to WAL are treated similarly as those related to column family operations, they are not applied to versions, but can be in a commit group. Mixing WAL related `VersionEdit`s with other types of edits will make logic in `ProcessManifestWrite` more complicated, so `VersionEdit`s related to WAL can either be WAL additions or deletions, like column family add and drop.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7256

Test Plan: a set of unit tests are added in `version_set_test.cc`

Reviewed By: riversand963

Differential Revision: D23123238

Pulled By: cheng-chang

fbshipit-source-id: 246be2ed4744fd03fa2738aba408aaa611d0379c

Summary:
To minimize dependencies for Ribbon filter code in progress,
core part of coding.h for fixed sizes has been moved to coding_lean.h.
Also, generic versions of these functions have been added to math128.h
(since the generic versions are likely only to be used along with
Unsigned128).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7587

Test Plan: Unit tests added for new functions

Reviewed By: jay-zhuang

Differential Revision: D24486718

Pulled By: pdillinger

fbshipit-source-id: a69768f742379689442135fa52237c01dfe2647e

Summary:
In addition to trace block cache access, we want to support trace queries on MySQL. To achieve that StartTrace and EndTrace need to be added to the stackable_db.h

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7585

Reviewed By: zhichao-cao

Differential Revision: D24482306

Pulled By: nmjnmjnmj

fbshipit-source-id: de641b4837c64cd33b44b5bebaeae5d1527c8c31

Summary:
As suggested by pdillinger ,The name of kLogFile is misleading, in some tests, kLogFile is defined as info log. Replace it with kWalFile and move it to public, which will be used in https://github.com/facebook/rocksdb/issues/7523

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7580

Test Plan: make check

Reviewed By: riversand963

Differential Revision: D24485420

Pulled By: zhichao-cao

fbshipit-source-id: 955e3dacc1021bb590fde93b0a568ffe9ad80799

Summary:
This commit makes https://github.com/facebook/rocksdb/issues/6262's code change tidier and easier to understand by:

1. Wrapping parallel compression initialization and termination into
   common methods;
2. Wrapping BlockRep initialization, push/pop into common methods;
3. Wrapping file size estimation into common methods;
4. Fixing function declarations that use non-const reference;
5. Fixing some uninitialized variables;
6. Fixing first_block data race;
7. Making BlockRep::status check in BlockBasedTableBuilder::Finish only present
if ok();
8. Making assert(ok()) in BlockBasedTableBuilder::CompressAndVerifyBlock only
present in non-parallel compression mode. In parallel compression mode,
compression will abort if status is not OK;
9. Eliminating potential data race caused by BlockBasedTableBuilder::GetStatus()
and BlockBasedTableBuilder::GetIOStatus() by returning status copy instead of
unprotected reference.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6888

Reviewed By: ajkr

Differential Revision: D21957110

Pulled By: jay-zhuang

fbshipit-source-id: 3a29892f249209513f030349756cecd7736eae80

Summary:
Remove function calling in assert statement as assert is a no
op in opt build and that function might not be called. This causes hang
in closing RocksDB when refit level is set.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7581

Test Plan: make check -j64

Reviewed By: riversand963

Differential Revision: D24466420

Pulled By: akankshamahajan15

fbshipit-source-id: 97db4ec5a95ae693c3290e176a3c12a9b1ad2f6d

Summary:
When `ASSERT_STATUS_CHECKED` is enabled, `transaction_test` does not pass without this PR.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7572

Test Plan: `ASSERT_STATUS_CHECKED=1 make   -j32 transaction_test && ./transaction_test`

Reviewed By: zhichao-cao

Differential Revision: D24404319

Pulled By: cheng-chang

fbshipit-source-id: 13689035995366ab06d8eada3ea404e45fef8bc5

Summary:
Without this PR, `ASSERT_STATUS_CHECKED=1 make   -j32 write_batch_test && ./write_batch_test` fails.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7575

Test Plan: ASSERT_STATUS_CHECKED=1 make   -j32 write_batch_test && ./write_batch_test

Reviewed By: zhichao-cao

Differential Revision: D24411442

Pulled By: cheng-chang

fbshipit-source-id: f67dc43c44d6afcc6d7e5ff15c6ae9bbf4dfc943

Summary:
Further refinement of the earlier PR.  Now the Status is NotFound with a subcode of PathNotFound. Also the existing functions for options parsing/loading are reverted to return InvalidArgument no matter in which way the user-provided arguments are deemed invalid.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7563

Reviewed By: zhichao-cao

Differential Revision: D24422491

Pulled By: ajkr

fbshipit-source-id: ba6b237cd0584d3f925c5ba0d349aeb8c250af67

Summary:
as title

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7571

Test Plan: make check

Reviewed By: zhichao-cao

Differential Revision: D24392577

Pulled By: cheng-chang

fbshipit-source-id: c94f92db48270d0e215aa0f2782b0ff2e31bf708

Summary:
Ignore read error in 'FilePrefetchBuffer::TryReadFromCache' as status is ignored
and  bool value is returned. Return error if prefetch fails in
'PrefetchTail' as we have planned to return Prefetch failures to users.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7574

Test Plan:
make check -j64,
python -u tools/db_crashtest.py blackbox

Reviewed By: zhichao-cao

Differential Revision: D24408825

Pulled By: akankshamahajan15

fbshipit-source-id: feebda771415998253fbe54632f13e6e75b7a243

Summary:
This PR adds support for writing a location identifier of the DB host to SST files as a table property. By default, the hostname is used, but can be overridden by the user. There have been some recent corruptions in files written by ```SstFileWriter``` before checksumming, so this property can be used to trace it back to the writing host and checking the host for hardware isues.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7479

Test Plan: Add new unit tests

Reviewed By: pdillinger

Differential Revision: D24340671

Pulled By: anand1976

fbshipit-source-id: 2038949fd8d160c0633ccb4f9da77740f19fa2a2

Summary:
In order to be able to introduce more locking protocols, we need to abstract out the locking subsystem in TransactionDB into a set of interfaces.

PR https://github.com/facebook/rocksdb/pull/7013 introduces interface `LockTracker`. This PR is a follow up to take the first step to abstract out a `LockManager` interface.

Further modifications to the interface may be needed when introducing the first implementation of range lock. But the idea here is to put the range lock implementation based on range tree under the `utilities/transactions/lock/range/range_tree`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7532

Test Plan: point_lock_manager_test

Reviewed By: ajkr

Differential Revision: D24238731

Pulled By: cheng-chang

fbshipit-source-id: 2a9458cd8b3fb008d9529dbc4d3b28c24631f463

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/7501

Reviewed By: ltamasi

Differential Revision: D24344109

Pulled By: pdillinger

fbshipit-source-id: d9a2b1b1cc8c8d8a96f13b8ae6814380caa10c96

Summary:
Fixes the URL for the badge and link.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7561

Reviewed By: ltamasi

Differential Revision: D24336928

Pulled By: pdillinger

fbshipit-source-id: 41e04a5b036458e303aac3ae3b6129f572f0e9ce

Summary:
The patch adds blob file support to the `Get` API by extending `Version` so that
whenever a blob reference is read from a file, the blob is retrieved from the corresponding
blob file and passed back to the caller. (This is assuming the blob reference is valid
and the blob file is actually part of the given `Version`.) It also introduces a cache
of `BlobFileReader`s called `BlobFileCache` that enables sharing `BlobFileReader`s
between callers. `BlobFileCache` uses the same backing cache as `TableCache`, so
`max_open_files` (if specified) limits the total number of open (table + blob) files.

TODO: proactively open/cache blob files and pin the cache handles of the readers in the
metadata objects similarly to what `VersionBuilder::LoadTableHandlers` does for
table files.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7540

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D24260219

Pulled By: ltamasi

fbshipit-source-id: a8a2a4f11d3d04d6082201b52184bc4d7b0857ba

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/7560

Reviewed By: akankshamahajan15

Differential Revision: D24323048

Pulled By: zhichao-cao

fbshipit-source-id: 2094ef089c37f570d4ea30d28d2f46f9fa1ce0f1

Summary:
Make LoadLatestOptions return PathNotFound if the options file does not exist.  Added tests for the LoadOptions related methods.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7554

Reviewed By: akankshamahajan15

Differential Revision: D24298985

Pulled By: zhichao-cao

fbshipit-source-id: c9ae3cb12fc4a5bbef07743e1c1300f98a2441b3

Summary:
* Avoid some unnecessary array copy operations on read/write
* Remove some duplicated code
* Don't leak arrays on some exceptions
* Fixed some doc comments

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7371

Reviewed By: jay-zhuang

Differential Revision: D24312932

Pulled By: pdillinger

fbshipit-source-id: 422fe6b98bbdb922a148922ac0d2d965c715176e

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/7550

Reviewed By: jay-zhuang

Differential Revision: D24315343

Pulled By: ajkr

fbshipit-source-id: fc7855b630a50c00dcb940241942295932732f39

Summary:
- Takes the burden off developer to close ColumnFamilyHandle instances before closing RocksDB instance
- The change is backward-compatible

----
Previously the pattern for working with Column Families was:

```java
try (final ColumnFamilyOptions cfOpts = new ColumnFamilyOptions().optimizeUniversalStyleCompaction()) {

  // list of column family descriptors, first entry must always be default column family
  final List<ColumnFamilyDescriptor> cfDescriptors = Arrays.asList(
      new ColumnFamilyDescriptor(RocksDB.DEFAULT_COLUMN_FAMILY, cfOpts),
      new ColumnFamilyDescriptor("my-first-columnfamily".getBytes(), cfOpts)
  );

  // a list which will hold the handles for the column families once the db is opened
  final List<ColumnFamilyHandle> columnFamilyHandleList =
      new ArrayList<>();

  try (final DBOptions options = new DBOptions()
      .setCreateIfMissing(true)
      .setCreateMissingColumnFamilies(true);
       final RocksDB db = RocksDB.open(options,
           "path/to/do", cfDescriptors,
           columnFamilyHandleList)) {

    try {

      // do something

    } finally {

      // NOTE user must explicitly frees the column family handles before freeing the db
      for (final ColumnFamilyHandle columnFamilyHandle :
          columnFamilyHandleList) {
        columnFamilyHandle.close();
      }
    } // frees the column family options
  }
} // frees the db and the db options
```

With the changes in this PR, the Java user no longer has to worry about manually closing the Column Families, which allows them to write simpler symmetrical create/free oriented code like this:

```java
try (final ColumnFamilyOptions cfOpts = new ColumnFamilyOptions().optimizeUniversalStyleCompaction()) {

  // list of column family descriptors, first entry must always be default column family
  final List<ColumnFamilyDescriptor> cfDescriptors = Arrays.asList(
      new ColumnFamilyDescriptor(RocksDB.DEFAULT_COLUMN_FAMILY, cfOpts),
      new ColumnFamilyDescriptor("my-first-columnfamily".getBytes(), cfOpts)
  );

  // a list which will hold the handles for the column families once the db is opened
  final List<ColumnFamilyHandle> columnFamilyHandleList =
      new ArrayList<>();

  try (final DBOptions options = new DBOptions()
      .setCreateIfMissing(true)
      .setCreateMissingColumnFamilies(true);
       final RocksDB db = RocksDB.open(options,
           "path/to/do", cfDescriptors,
           columnFamilyHandleList)) {

        // do something

    } // frees the column family options, then frees the db and the db options
  }
}
```

**NOTE**: The changes in this PR are backwards API compatible, which means existing code using the original approach will also continue to function correctly.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7428

Reviewed By: cheng-chang

Differential Revision: D24063348

Pulled By: jay-zhuang

fbshipit-source-id: 648d7526669923128c863ead94516bf4d50ac658

Summary:
fix for clang_analyzer build failure in table_test because of
potential memory leak of memtable in case of ASSERT failure.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7553

Test Plan:
USE_CLANG=1 make analyze;
           make check -j64

Reviewed By: jay-zhuang

Differential Revision: D24295042

Pulled By: akankshamahajan15

fbshipit-source-id: e9ea184367970fff3b520e33f3ceebf28d66ac8d