Summary:
Build with "USE_HDFS" failed with below errors on Windows. This PR is trying to fix them
Severity	Code	Description	Project	File	Line	Suppression State
Error (active)	E0020	identifier "ssize_t" is undefined	rocksdb	D:\Git\rocksdb\rocksdb\env\env_hdfs.cc	127
Error (active)	E1696	cannot open source file "sys/time.h"	rocksdb	D:\Git\rocksdb\rocksdb\env\env_hdfs.cc	15
Error	C2065	'pthread_t': undeclared identifier	rocksdb	d:\git\rocksdb\rocksdb\hdfs\env_hdfs.h	166
Error	C3861	'pthread_self': identifier not found	rocksdb	d:\git\rocksdb\rocksdb\hdfs\env_hdfs.h	167
Error	C1083	Cannot open include file: 'sys/time.h': No such file or directory	rocksdb	d:\git\rocksdb\rocksdb\env\env_hdfs.cc	15
Error	C2065	'pthread_t': undeclared identifier	db_bench	d:\git\rocksdb\rocksdb\hdfs\env_hdfs.h	166
Error	C3861	'pthread_self': identifier not found	db_bench	d:\git\rocksdb\rocksdb\hdfs\env_hdfs.h	167
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6950

Test Plan:
1. manually test build with "USE_HDFS" on Windows, verified HDFS Env related function by db_bench.exe.
D:\Git\rocksdb\build\Debug>db_bench.exe --hdfs="abfs://test@rdbtest2.dfs.core.windows.net" --num=100 --benchmarks="fillseq,readseq,fillseekseq" --db="abfs://test@rdbtest2.dfs.core.windows.net/test"
2020-06-05 20:42:21,102 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
2020-06-05 20:42:22,646 WARN utils.SSLSocketFactoryEx: Failed to load OpenSSL. Falling back to the JSSE default.
Initializing RocksDB Options from the specified file
Initializing RocksDB Options from command-line flags
RocksDB:    version 6.10
Keys:       16 bytes each
Values:     100 bytes each (50 bytes after compression)
Entries:    100
Prefix:    0 bytes
Keys per prefix:    0
RawSize:    0.0 MB (estimated)
FileSize:   0.0 MB (estimated)
Write rate: 0 bytes/second
Read rate: 0 ops/second
Compression: Snappy
Compression sampling rate: 0
Memtablerep: skip_list
Perf Level: 1
WARNING: Assertions are enabled; benchmarks unnecessarily slow
------------------------------------------------
Initializing RocksDB Options from the specified file
Initializing RocksDB Options from command-line flags
DB path: [abfs://test@rdbtest2.dfs.core.windows.net/test]
fillseq      :    1138.350 micros/op 877 ops/sec;    0.1 MB/s
DB path: [abfs://test@rdbtest2.dfs.core.windows.net/test]
readseq      :      63.580 micros/op 15627 ops/sec;    1.7 MB/s
DB path: [abfs://test@rdbtest2.dfs.core.windows.net/test]
fillseekseq  :      45.615 micros/op 21762 ops/sec;

Reviewed By: cheng-chang

Differential Revision: D21964806

Pulled By: riversand963

fbshipit-source-id: 9d7413178ece0113d11bc4398583f7d0590d5dbd

Summary:
The CircleCI's Clang flavor has a bug that doesn't really use CLANG. Fix it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6965

Test Plan: See CI results.

Reviewed By: pdillinger

Differential Revision: D22025355

fbshipit-source-id: e86922b9152e9f5732e5099d0ce41da9226ff806

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6972

Reviewed By: zhichao-cao

Differential Revision: D22021953

Pulled By: ajkr

fbshipit-source-id: 4debbafe45b5939fd28549230eebf6006eb43440

Summary:
The `FileMetaData` objects associated with table files already contain the
number of the oldest blob file referenced by the SST in question. This patch
adds the inverse mapping to `BlobFileMetaData`, namely the set of table file
numbers for which the oldest blob file link points to the given blob file (these
are referred to as *linked SSTs*). This mapping will be used by the GC logic.

Implementation-wise, the patch builds on the `BlobFileMetaDataDelta`
functionality introduced in https://github.com/facebook/rocksdb/pull/6835: newly linked/unlinked SSTs are
accumulated in `BlobFileMetaDataDelta`, and the changes to the linked SST set
are applied in one shot when the new `Version` is saved. The patch also reworks
the blob file related consistency checks in `VersionBuilder` so they validate the
consistency of the forward table file -> blob file links and the backward blob file ->
table file links for blob files that are part of the `Version`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6945

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D21912228

Pulled By: ltamasi

fbshipit-source-id: c5bc7acf6e729a8fccbb12672dd5cd00f6f000f8

Summary:
If `options.wal_recovery_mode == WALRecoveryMode::kPointInTimeRecovery`, RocksDB stops replaying WAL once hitting an error and discards the rest of the WAL. This can lead to data loss if the error occurs at an offset smaller than the last sync'ed offset.
Ideally, RocksDB point-in-time recovery should permit recovery if the error occurs after last synced offset while fail recovery if error occurs before the last synced offset. However, RocksDB does not track the synced offset of WALs. Consequently, RocksDB does not know whether an error occurs before or after the last synced offset. An error can be one of the following.
- WAL record checksum mismatch. This can result from both corruption of synced data and dropping of unsynced data during shutdown. We cannot be sure which one. In order not to defeat the original motivation to permit the latter case, we keep the original behavior of point-in-time WAL recovery.
- IOError. This means the WAL can be bad, an indicator of whole file becoming unavailable, not to mention synced part of the WAL. Therefore, we choose to modify the behavior of point-in-time recovery and fail the database recovery.

Test plan (devserver):
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6963

Reviewed By: ajkr

Differential Revision: D22011083

Pulled By: riversand963

fbshipit-source-id: f9cbf29a37dc5cc40d3fa62f89eed1ad67ca1536

Summary:
https://github.com/facebook/rocksdb/pull/6901 subtly changed the handling of the corner case
when a table file is deleted from a level, then re-added to the same level. (Note: this
should be extremely rare; one scenario that comes to mind is a trivial move followed by
a call to `ReFitLevel` that moves the file back to the original level.) Before that change,
a new `FileMetaData` object was created as a result of this sequence; after the change,
the original `FileMetaData` was essentially resurrected (since the deletion and the addition
simply cancel each other out with the change). This patch restores the original behavior,
which is more intuitive considering the interface, and in sync with how trivial moves are handled.
(Also note that `FileMetaData` contains some mutable data members, the values of which
might be different in the resurrected object and the freshly created one.)
The PR also fixes a bug in this area: with the original pre-6901 code, `VersionBuilder`
would add the same file twice to the same level in the scenario described above.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6939

Test Plan: `make check`

Reviewed By: ajkr

Differential Revision: D21905580

Pulled By: ltamasi

fbshipit-source-id: da07ae45384ecf3c6c53506d106432d88a7ec9df

Summary:
`DBTest2.CompressionFailures` currently tests many configurations
sequentially using nested loops, which often leads to timeouts
in our test system. The patch turns it into a parameterized test
instead.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6968

Test Plan: `make check`

Reviewed By: siying

Differential Revision: D22006954

Pulled By: ltamasi

fbshipit-source-id: f71f2f7108086b7651ecfce3d79a7fab24620b2c

Summary:
Application can ingest SST files with file checksum information, such that during ingestion, DB is able to check data integrity and identify of the SST file. The PR introduces generate_and_verify_file_checksum to IngestExternalFileOption to control if the ingested checksum information should be verified with the generated checksum.

    1. If generate_and_verify_file_checksum options is *FALSE*: *1)* if DB does not enable SST file checksum, the checksum information ingested will be ignored; *2)* if DB enables the SST file checksum and the checksum function name matches the checksum function name in DB, we trust the ingested checksum, store it in Manifest. If the checksum function name does not match, we treat that as an error and fail the IngestExternalFile() call.
    2. If generate_and_verify_file_checksum options is *TRUE*: *1)* if DB does not enable SST file checksum, the checksum information ingested will be ignored; *2)* if DB enable the SST file checksum, we will use the checksum generator from DB to calculate the checksum for each ingested SST files after they are copied or moved. Then, compare the checksum results with the ingested checksum information: _A)_ if the checksum function name does not match, _verification always report true_ and we store the DB generated checksum information in Manifest. _B)_ if the checksum function name mach, and checksum match, ingestion continues and stores the checksum information in the Manifest. Otherwise, terminate file ingestion and report file corruption.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6891

Test Plan: added unit test, pass make asan_check

Reviewed By: pdillinger

Differential Revision: D21935988

Pulled By: zhichao-cao

fbshipit-source-id: 7b55f486632db467e76d72602218d0658aa7f6ed

Summary:
This is required so that the test cases can safely be run in parallel.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6962

Test Plan: `make check`

Reviewed By: zhichao-cao

Differential Revision: D21980060

Pulled By: ltamasi

fbshipit-source-id: 616b7a0b686155d3874848b9098c67ad3f47efcc

Summary:
This saves up to two key comparisons in block seeks. The first key
comparison saved is a redundant key comparison against the restart key
where the linear scan starts. This comparison is saved in all cases
except when the found key is in the first restart interval. The
second key comparison saved is a redundant key comparison against the
restart key where the linear scan ends. This is only saved in cases
where all keys in the restart interval are less than the target
(probability roughly `1/restart_interval`).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6646

Test Plan:
ran a benchmark with mostly default settings and counted key comparisons

before: `user_key_comparison_count = 19399529`
after: `user_key_comparison_count = 18431498`

setup command:

```
$ TEST_TMPDIR=/dev/shm/dbbench ./db_bench -benchmarks=fillrandom,compact -write_buffer_size=1048576 -target_file_size_base=1048576 -max_bytes_for_level_base=4194304 -max_background_jobs=12 -level_compaction_dynamic_level_bytes=true -num=10000000
```

benchmark command:

```
$ TEST_TMPDIR=/dev/shm/dbbench/ ./db_bench -use_existing_db=true -benchmarks=readrandom -disable_auto_compactions=true -num=10000000 -compression_type=none -reads=1000000 -perf_level=3
```

Reviewed By: pdillinger

Differential Revision: D20849707

Pulled By: ajkr

fbshipit-source-id: 1f01c5cd99ea771fd27974046e37b194f1cdcfac

Summary:
Memory pinned by `pin_l0_filter_and_index_blocks_in_cache` needs to be predictable based on user config. This PR makes sure
we do not pin extra memory for large files generated by intra-L0 (see https://github.com/facebook/rocksdb/issues/6889).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6911

Test Plan: unit test

Reviewed By: siying

Differential Revision: D21835818

Pulled By: ajkr

fbshipit-source-id: a11a088549d06bed8aacc2548d266e5983f0ead4

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6960

Test Plan: `make check`

Reviewed By: zhichao-cao

Differential Revision: D21958416

Pulled By: ltamasi

fbshipit-source-id: 97cf05027b7363014b07836e7f158c23827bd661

Summary:
as title
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6951

Test Plan: tests included + manual

Reviewed By: ajkr

Differential Revision: D21918540

Pulled By: pdillinger

fbshipit-source-id: 79d4991f2a831214fc7e477a839ec19dbbace6c5

Summary:
Moving towards the long term goal of moving most CI build to CircleCI when possible, add some Linux tests in CircleCI. This is not all what we can include to CircleCI. For example, Java builds are not includ
ed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6937

Test Plan: Watch CI build results.

Reviewed By: pdillinger

Differential Revision: D21941605

fbshipit-source-id: db6aead3c45f523386d4fb30d224cfde573cccad

Summary:
When MultiGet is called with duplicate keys, and the key matches the
largest key in an SST file and the value type is merge, only the first
instance of the duplicate key is returned with correct results. This is
due to the incorrect assumption that if a key in a batch is equal to the
largest key in the file, the next key cannot be present in that file.

Tests:
Add a new unit test
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6953

Reviewed By: cheng-chang

Differential Revision: D21935898

Pulled By: anand1976

fbshipit-source-id: a2cc327a15150e23fd997546ca64d1c33021cb4c

Summary:
The patch adds a convenience method `GetFileMetaDataByNumber` that
builds on the `FileLocation` functionality introduced recently (see
https://github.com/facebook/rocksdb/pull/6862). This method makes it possible to
retrieve the `FileMetaData` directly as opposed to having to go through
`LevelFiles` and friends.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6940

Test Plan: `make check`

Reviewed By: cheng-chang

Differential Revision: D21905946

Pulled By: ltamasi

fbshipit-source-id: af99e19de21242b2b4a87594a535c6028d16ee72

Summary:
Implemented a subcommand of sst_dump called identify, which determines whether a file is an SST file or identifies and lists all the SST files in a directory;

This update also fixes the problem that sst_dump exits with a success state even if target file/directory does not exist/is not an SST file/is empty/is corrupted.

One test is added to sst_dump_test.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6943

Test Plan: Passed make check and a few manual tests

Reviewed By: pdillinger

Differential Revision: D21928985

Pulled By: gg814

fbshipit-source-id: 9a8b48e0cf1a0e96b13f42b690aba8ad981afad3

Summary:
Since gflags use the global variable to store the flags passed in. In the unit test, if we git one flag per unit test, the result is that all the flags are combined together in the following tests. Therefore, it has the dependency. In this PR, we pass the full arguments each time to ensure that the old arguments will be overwritten by the new one such that the dependency is removed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6941

Test Plan: make asan_check. run each unit test in trace_analyzer_test independently and in arbitrary orders.

Reviewed By: pdillinger

Differential Revision: D21909176

Pulled By: zhichao-cao

fbshipit-source-id: dca550a0a4a205c30faa620e258a020a3b5b4e13

Summary:
In db_options.c, we should avoid including header files in the `db` directory to avoid introducing unnecessary dependency. The reason why `version_edit.h` has been included in `db_options.cc` is because we need two constants, `kUnknownChecksum` and `kUnknownChecksumFuncName`. We can put these two constants as `constexpr` in the public header `file_checksum.h`.

Test plan (devserver):
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6952

Reviewed By: zhichao-cao

Differential Revision: D21925341

Pulled By: riversand963

fbshipit-source-id: 2902f3b74c97f0cf16c58ad24c095c787c3a40e2

Summary:
RocksDB is an embedded library; we should not write to the application's
console. Note: in each case, the same information is returned in the form of a
`Status::Corruption` object.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6948

Test Plan: `make check`

Reviewed By: ajkr

Differential Revision: D21914965

Pulled By: ltamasi

fbshipit-source-id: ae4b66789aa6b659eb8cc2ed4a048187962c86cc

Summary:
We currently do not have any validation that would ensure that the `FileMetaData`
objects are equivalent when a file gets deleted from the LSM tree and then re-added
(think trivial moves); however, if we did, this test case would be in violation. The patch
changes the values used in the test case so they are consistent.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6942

Test Plan: `make check`

Reviewed By: zhichao-cao

Differential Revision: D21911366

Pulled By: ltamasi

fbshipit-source-id: 2f0486f8337373a6a111b6f28433d70507857104

Summary:
Remove the dead code in table test.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6946

Test Plan: run table_test

Reviewed By: riversand963

Differential Revision: D21913563

Pulled By: zhichao-cao

fbshipit-source-id: c0aa9f3b95dfe87dd7fb2cd4823784f08cb3ddd3

Summary:
Disable two OpenForReadOnly tests in the LITE mode
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6947

Test Plan: passed db_test2

Reviewed By: cheng-chang

Differential Revision: D21914345

Pulled By: gg814

fbshipit-source-id: 58e81baf5d8cf8adcedaef3966aa3a427bbdf7c2

Summary:
Make RocksDB run a predefined unit test so that it can be integrated with better tools.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6926

Test Plan: Watch tests

Reviewed By: pdillinger

Differential Revision: D21866216

fbshipit-source-id: cafca82efdf0b72671be8d30b665e88a75ae6000

Summary:
The ```for``` loop in ```VerifyChecksumInBlocks``` only checks ```index_iter->Valid()``` which could be ```false``` either due to reaching the end of the index or, in case of partitioned index, it could be due to a checksum mismatch error when reading a 2nd level index block. Instead of throwing away the index iterator status, we need to return any errors back to the caller.

Tests:
Add a test in block_based_table_reader_test.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6909

Reviewed By: pdillinger

Differential Revision: D21833922

Pulled By: anand1976

fbshipit-source-id: bc778ebf1121dbbdd768689de5183f07a9f0beae

Summary:
Currently, `DeleteDir` only deletes the directory if there are no other directories under the target dir. This PR makes it delete directories recursively.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6934

Test Plan:
Added a new unit test in testutil_test.cc.
`make testutil_test`

Reviewed By: zhichao-cao

Differential Revision: D21884211

Pulled By: cheng-chang

fbshipit-source-id: 0b9a48a200f494ee007aef5d1763b4aa331f8b5a

Summary:
Add logs and stats for files marked as trash and files deleted immediately in DeleteScheduler
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6927

Test Plan: make check -j64

Reviewed By: riversand963

Differential Revision: D21869068

Pulled By: akankshamahajan15

fbshipit-source-id: e9f673c4fa8049ce648b23c75d742f2f9c6c57a1

Summary:
Confusing checks for null that are never null
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6933

Test Plan: make check

Reviewed By: cheng-chang

Differential Revision: D21885466

Pulled By: pdillinger

fbshipit-source-id: 4b48e03c2a33727f2702b0d12292f9fda5a3c475

Summary:
Mostly uninitialized values: some probably written before use, but some seem like bugs. Also, destructor needs to be virtual, and possible use-after-free in test
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6935

Test Plan: make check

Reviewed By: siying

Differential Revision: D21885484

Pulled By: pdillinger

fbshipit-source-id: e2e7cb0a0cf196f2b55edd16f0634e81f6cc8e08

Summary:
When operation on an open file descriptor fails, we should close the file descriptor.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6936

Test Plan: make check

Reviewed By: pdillinger

Differential Revision: D21885458

Pulled By: riversand963

fbshipit-source-id: ba077a76b256a8537f21e22e4ec198f45390bf50

Summary:
StringAppendOperatorTest right now runs in a mode where RUN_ALL_TESTS() is executed twice for the same test but different settings. This creates a problem with a tool that expects every test to run once. Fix it by using a parameterized test instead.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6930

Test Plan: Run the test and see it passed.

Reviewed By: ltamasi

Differential Revision: D21874145

fbshipit-source-id: 55520b2d7f1ba9f3cba1e2d087fe86f43fb06145

Summary:
When running ThreadLocalTest.SequentialReadWriteTest individually, the test fails with:

] ./thread_local_test --gtest_filter="*SequentialReadWriteTest*"
Note: Google Test filter = *SequentialReadWriteTest*
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from ThreadLocalTest
[ RUN      ] ThreadLocalTest.SequentialReadWriteTest
internal_repo_rocksdb/repo/util/thread_local_test.cc:144: Failure
      Expected: IDChecker::PeekId()
      Which is: 3
To be equal to: base_id + 1u
      Which is: 2
[  FAILED  ] ThreadLocalTest.SequentialReadWriteTest (1 ms)
[----------] 1 test from ThreadLocalTest (1 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (1 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] ThreadLocalTest.SequentialReadWriteTest

 1 FAILED TEST

It appears that when running as the first test, PeakId() was updated twice. I didn't dig into it why but it doesn't seem to break the contract. Relax the assertion to make it pass.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6929

Test Plan: Run the test individually and as the whole thread_local_test

Reviewed By: riversand963

Differential Revision: D21873999

fbshipit-source-id: 1dcb6a2e9c38b6afd848027308bfe633342b7548

Summary:
The LDB create and drop column family commands failed to check if theere was a valid database prior to dereferencing it, leading to a core dump.

The SstFileDumper prefetch code would dereference a file when the file did not exist as part of the Prefetch code.  This dereference was moved inside an st.ok() check.

Tests were added for both failure conditions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6922

Reviewed By: gg814

Differential Revision: D21884024

Pulled By: pdillinger

fbshipit-source-id: bddd45c299aa9dc7e928c17a37a96521f8c9149e

Summary:
When run */RunMany/* tests individually, e.g. ChrootEnvWithDirectIO/EnvPosixTestWithParam.RunMany/0, they hang. It's because they insert to background thread pool without initializing them. Fix it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6931

Test Plan: Run ChrootEnvWithDirectIO/EnvPosixTestWithParam.RunMany/0 by itself and see it passes.

Reviewed By: riversand963

Differential Revision: D21875603

fbshipit-source-id: 7f848174c1a660254a2b1f7e11cca5370793ba30

Summary:
As title. The prior change to the line is a typo. Fixing it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6928

Test Plan: make check

Reviewed By: zhichao-cao

Differential Revision: D21873587

Pulled By: riversand963

fbshipit-source-id: f4837fc8792d7106bc230b7b499dfbb7a2847430

API change: DB::OpenForReadOnly will not write to the file system unless create_if_missing is true (#6900)

Summary:
DB::OpenForReadOnly will not write anything to the file system (i.e., create directories or files for the DB) unless create_if_missing is true.

This change also fixes some subcommands of ldb, which write to the file system even if the purpose is for readonly.

Two tests for this updated behavior of DB::OpenForReadOnly are also added.

Other minor changes:
1. Updated HISTORY.md to include this API change of DB::OpenForReadOnly;
2. Updated the help information for the put and batchput subcommands of ldb with the option [--create_if_missing];
3. Updated the comment of Env::DeleteDir to emphasize that it returns OK only if the directory to be deleted is empty.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6900

Test Plan: passed make check; also manually tested a few ldb subcommands

Reviewed By: pdillinger

Differential Revision: D21822188

Pulled By: gg814

fbshipit-source-id: 604cc0f0d0326a937ee25a32cdc2b512f9a3be6e

Summary:
We recently removed the dependencies of core components on gtest. Add a Travis test to make sure it doesn't regress. Change cmake setting so that the gtest related components are only included when tests, benchmarks or stress tools are included in the build. Add this build setting in Travis to confirm it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6921

Test Plan: See Travis passes

Reviewed By: ajkr

Differential Revision: D21863564

fbshipit-source-id: df26f50a8305a04ff19ffa8069a1857ecee10289

Summary:
Additionally I have extended the incomplete test added in the https://github.com/facebook/rocksdb/issues/6880.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6925

Reviewed By: ajkr

Differential Revision: D21869788

Pulled By: pdillinger

fbshipit-source-id: e9db80f259c57ca1bdcbc2c66cb938cb1ac26e48

Summary:
This reverts commit 8d87e9ce.

Based on offline discussions, it's too early to upgrade to gtest 1.10, as it prevents some developers from using an older version of gtest to integrate to some other systems. Revert it for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6923

Reviewed By: pdillinger

Differential Revision: D21864799

fbshipit-source-id: d0726b1ff649fc911b9378f1763316200bd363fc

Summary:
GetTestDirectory implies a file system operation (it creates the
default test directory if missing), so it should be routed to
the FileSystem rather than the Env.

Also remove the GetTestDirectory implementation in the PosixEnv,
since it overrides GetTestDirectory in CompositeEnv making it
impossible to override with a custom FileSystem.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6896

Reviewed By: cheng-chang

Differential Revision: D21868984

Pulled By: ajkr

fbshipit-source-id: e79bfef758d06dacef727c54b96abe62e78726fd