Summary:
This test uses database functionality and required more extensive work to get it to pass than the other tests. The DB functionality required for this test now passes the check.
When it was unclear what the proper behavior was for unchecked status codes, a TODO was added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7283
Reviewed By: akankshamahajan15
Differential Revision: D23251497
Pulled By: ajkr
fbshipit-source-id: 52b79629bdafa0a58de8ead1d1d66f141b331523
Summary:
This diff contains following changes:
1. Replace `FSSequentialFile` pointer with `FSSequentialFilePtr` object that wraps `FSSequentialFile` pointer in `SequenceFileReader`.
Objective: If tracing is enabled, `FSSequentialFilePtr` returns `FSSequentialFileTracingWrapper` pointer that includes all necessary information in `IORecord` and calls underlying FileSystem and invokes `IOTracer` to dump that record in a binary file. If tracing is disabled then, underlying `FileSystem` pointer is returned directly. `FSSequentialFilePtr` wrapper class is added to bypass the `FSSequentialFileTracingWrapper` when tracing is disabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7190
Test Plan:
make check -j64
COMPILE_WITH_TSAN=1 make check -j64
Reviewed By: anand1976
Differential Revision: D23059616
Pulled By: akankshamahajan15
fbshipit-source-id: 1564b94dd1297cd0fbfe2ed5c9cc3e20f7395301
Summary:
This pull request adds the parameter --fs_uri to db_bench and db_stress, creating a composite env combining the default env with a specified registered rocksdb file system.
This makes it easier to develop and test new RocksDB FileSystems.
The pull request also registers the posix file system for testing purposes.
Examples:
```
$./db_bench --fs_uri=posix:// --benchmarks=fillseq
$./db_stress --fs_uri=zenfs://nullb1
```
zenfs is a RocksDB FileSystem I'm developing to add support for zoned block devices, and in that case the zoned block device is specified in the uri (a zoned null block device in the above example).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6878
Reviewed By: siying
Differential Revision: D23023063
Pulled By: ajkr
fbshipit-source-id: 8b3fe7193ce45e683043b021779b7a4d547af247
Summary:
As part of the IOTracing project, this PR
1. Caches "FileSystemPtr" object(wrapper class that returns file system pointer based on tracing enabled) instead of "FileSystem" pointer.
2. FileSystemPtr object is created using FileSystem pointer and IOTracer
pointer.
3. IOTracer shared_ptr is created in DBImpl and it is passed to different classes through constructor.
4. When tracing is enabled through DB::StartIOTrace, FileSystemPtr
returns FileSystemTracingWrapper pointer for tracing purpose and when
it is disabled underlying FileSystem pointer is returned.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7180
Test Plan:
make check -j64
COMPILE_WITH_TSAN=1 make check -j64
Reviewed By: anand1976
Differential Revision: D22987117
Pulled By: akankshamahajan15
fbshipit-source-id: 6073617e4c2d5bc363914f3a1f55ae3b0a58fbf1
Summary:
A colon will be added after 'msg' automatically when invoke function Status(Code _code, const Slice& msg, const Slice& msg2),
it's not needed to append a colon explicitly to 'msg'.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7041
Reviewed By: ajkr
Differential Revision: D22292801
fbshipit-source-id: 8f2d69065bb779d2613468bf9fc9169f32c3f1ec
Summary:
Make (most of) the env*_test pass when ASSERT_STATUS_CHECKED is enabled.
One test that opens a database is currently disabled in this mode, as there are many errors that need revisited for DB tests and status checks.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7176
Reviewed By: cheng-chang
Differential Revision: D22799278
Pulled By: ajkr
fbshipit-source-id: 16d8a02eaeecd6df1060249b6a5811292801f2ed
Summary:
1. Add the wrapper classes FileSystemTracingWrapper, FSSequentialFileTracingWrapper, FSRandomAccessFileTracingWrapper, FSWritableFileTracingWrapper, FSRandomRWFileTracingWrapper that forward the calls to underlying storage system and then pass the file operation information to IOTracer. IOTracer dumps the record in binary format for tracing.
2. Add the wrapper classes FileSystemPtr, FSSequentialFilePtr, FSRandomAccessFilePtr, FSWritableFilePtr and FSRandomRWFilePtr that overload operator-> and return ptr to underlying storage system or Tracing wrapper class based on enabling/disabling of IO tracing. These classes are added to bypass Tracing Wrapper classes when we disable tracing.
3. Add enums in trace.h that distinguish which options need to be added for different file operations(Read, close, write etc) as part of tracing record.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7002
Test Plan: make check -j64
Reviewed By: anand1976
Differential Revision: D22127897
Pulled By: akankshamahajan15
fbshipit-source-id: 74cff58ce5661c9a3832dfaa52483f3b2d8565e0
Summary:
Cleans up some of the dependencies on test code in the Makefile while building tools:
- Moves the test::RandomString, DBBaseTest::RandomString into Random
- Moves the test::RandomHumanReadableString into Random
- Moves the DestroyDir method into file_utils
- Moves the SetupSyncPointsToMockDirectIO into sync_point.
- Moves the FaultInjection Env and FS classes under env
These changes allow all of the tools to build without dependencies on test_util, thereby simplifying the build dependencies. By moving the FaultInjection code, the dependency in db_stress on different libraries for debug vs release was eliminated.
Tested both release and debug builds via Make and CMake for both static and shared libraries.
More work remains to clean up how the tools are built and remove some unnecessary dependencies. There is also more work that should be done to get the Makefile and CMake to align in their builds -- what is in the libraries and the sizes of the executables are different.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7097
Reviewed By: riversand963
Differential Revision: D22463160
Pulled By: pdillinger
fbshipit-source-id: e19462b53324ab3f0b7c72459dbc73165cc382b2
Summary:
Some tests directly uses TmpDir() as temporary directory without adding any randomize factor. This would cause failures when tests run in parallel. Fix it by moving some of them to test::PerThreadDBPath()
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7030
Test Plan: Watch existing tests pass
Reviewed By: zhichao-cao
Differential Revision: D22224710
fbshipit-source-id: 28c9932fede0a4a64670e5b5fdb08f4fb5dccdd0
Summary:
It's useful to build RocksDB using a more recent clang version in CI. Add a CircleCI build and fix some issues with it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7025
Test Plan: See all tests pass.
Reviewed By: pdillinger
Differential Revision: D22215700
fbshipit-source-id: 914a729c2cd3f3ac4a627cc0ac58d4691dca2168
Summary:
EncryptEnv class is both declared and defined within env_encryption.cc. This makes it really tough to derive new classes from that base.
This branch moves declaration of the class to rocksdb/env_encryption.h. The change facilitates making new encryption modules (such as an upcoming openssl AES CTR pull request) possible / easy.
The only coding change was to add the EncryptEnv object to env_basic_test.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6830
Reviewed By: riversand963
Differential Revision: D21706593
Pulled By: ajkr
fbshipit-source-id: 64d2da95a1569ceeb9b1549c3bec5404cf4c89f0
Summary:
`Env::LowerThreadPoolCPUPriority` takes a new parameter `CpuPriority` to be able to lower to a specific priority such as `CpuPriority::kIdle`, previously, the priority is always lowered to `CpuPriority::kLow`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6969
Test Plan: unit test `EnvPosixTest::LowerThreadPoolCpuPriority` added to `env_test.cc`.
Reviewed By: siying
Differential Revision: D22011169
Pulled By: cheng-chang
fbshipit-source-id: 568878c24a924912e35cef00c552d4a63431cdf4
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:
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:
This reverts commit 8d87e9cea1.
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
Summary:
x.size() -1 or y - 1 can overflow to an extremely large value when x.size() pr y is 0 when they are unsigned type. The end condition of i in the for loop will be extremely large, potentially causes segment fault. Fix them.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6902
Test Plan: pass make asan_check
Reviewed By: ajkr
Differential Revision: D21843767
Pulled By: zhichao-cao
fbshipit-source-id: 5b8b88155ac5a93d86246d832e89905a783bb5a1
Summary:
If both direct IO and IO uring are enabled, when IO uring returns partial result, we'll try to read the remaining part of the request, but the starting address/offset of the remaining part might not be aligned to the block size, in direct IO mode, the unaligned offset causes bug.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6853
Test Plan: run make check with both direct IO and IO uring enabled, this is covered by one of the continuous tests.
Reviewed By: anand1976
Differential Revision: D21603023
Pulled By: cheng-chang
fbshipit-source-id: 942f6a11ff21e1892af6c4464e02bab4c707787c
Summary:
The dynamic_cast in the filter benchmark causes release mode to fail due to
no-rtti. Replace with static_cast_with_check.
Signed-off-by: Derrick Pallas <derrick@pallas.us>
Addition by peterd: Remove unnecessary 2nd template arg on all static_cast_with_check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6732
Reviewed By: ltamasi
Differential Revision: D21304260
Pulled By: pdillinger
fbshipit-source-id: 6e8eb437c4ca5a16dbbfa4053d67c4ad55f1608c
Summary:
In release mode, asserts are not compiled, so `r` is not used, causing compiler warnings.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6750
Test Plan: make check under release mode
Reviewed By: anand1976
Differential Revision: D21220365
Pulled By: cheng-chang
fbshipit-source-id: fd4afa9843d54af68c4da8660ec61549803e1167
Summary:
IsDirectory() is a common API to check whether a path is a regular file or
directory.
POSIX: call stat() and use S_ISDIR(st_mode)
Windows: PathIsDirectoryA() and PathIsDirectoryW()
HDFS: FileSystem.IsDirectory()
Java: File.IsDirectory()
...
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6711
Test Plan: make check
Reviewed By: anand1976
Differential Revision: D21053520
Pulled By: riversand963
fbshipit-source-id: 680aadfd8ce982b63689190cf31b3145d5a89e27
Summary:
Compilation fails on systems that do not support O_CLOEXEC. Fix it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6695
Test Plan: compile without O_CLOEXEC support
Reviewed By: anand1976
Differential Revision: D21011850
Pulled By: cheng-chang
fbshipit-source-id: f1bf1cce2aa65c7d10b5a9613e941db30e928347
Summary:
Add `encrypt_data_time` and `decrypt_data_time` perf_context counters to time encryption/decryption time when `EnvEncryption` is enabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6596
Test Plan: CI
Reviewed By: anand1976
Differential Revision: D20678617
fbshipit-source-id: 7b57536143aa38509cde011f704de33382169e07
Summary:
This change updates PosixSequentialFile::Read to call clearerr()
before fread()ing again after an EINTR is returned on a previous
fread.
The original fix is from bd8f1ebb91.
Fixing https://github.com/facebook/rocksdb/issues/6509
Signed-off-by: phantomape <cxucheng@outlook.com>
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6609
Reviewed By: zhichao-cao
Differential Revision: D20731482
Pulled By: riversand963
fbshipit-source-id: 7f1f3a1449077d5560f45c465a78d08633740ba0
Summary:
In the current code base, we use Status to get and store the returned status from the call. Specifically, for IO related functions, the current Status cannot reflect the IO Error details such as error scope, error retryable attribute, and others. With the implementation of https://github.com/facebook/rocksdb/issues/5761, we have the new Wrapper for IO, which returns IOStatus instead of Status. However, the IOStatus is purged at the lower level of write path and transferred to Status.
The first job of this PR is to pass the IOStatus to the write path (flush, WAL write, and Compaction). The second job is to identify the Retryable IO Error as HardError, and set the bg_error_ as HardError. In this case, the DB Instance becomes read only. User is informed of the Status and need to take actions to deal with it (e.g., call db->Resume()).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6487
Test Plan: Added the testing case to error_handler_fs_test. Pass make asan_check
Reviewed By: anand1976
Differential Revision: D20685017
Pulled By: zhichao-cao
fbshipit-source-id: ff85f042896243abcd6ef37877834e26f36b6eb0
Summary:
The current Env/FileSystem API separation has a couple of issues -
1. It requires the user to specify 2 options - ```Options::env``` and ```Options::file_system``` - which means they have to make code changes to benefit from the new APIs. Furthermore, there is a risk of accessing the same APIs in two different ways, through Env in the old way and through FileSystem in the new way. The two may not always match, for example, if env is ```PosixEnv``` and FileSystem is a custom implementation. Any stray RocksDB calls to env will use the ```PosixEnv``` implementation rather than the file_system implementation.
2. There needs to be a simple way for the FileSystem developer to instantiate an Env for backward compatibility purposes.
This PR solves the above issues and simplifies the migration in the following ways -
1. Embed a shared_ptr to the ```FileSystem``` in the ```Env```, and remove ```Options::file_system``` as a configurable option. This way, no code changes will be required in application code to benefit from the new API. The default Env constructor uses a ```LegacyFileSystemWrapper``` as the embedded ```FileSystem```.
1a. - This also makes it more robust by ensuring that even if RocksDB
has some stray calls to Env APIs rather than FileSystem, they will go
through the same object and thus there is no risk of getting out of
sync.
2. Provide a ```NewCompositeEnv()``` API that can be used to construct a
PosixEnv with a custom FileSystem implementation. This eliminates an
indirection to call Env APIs, and relieves the FileSystem developer of
the burden of having to implement wrappers for the Env APIs.
3. Add a couple of missing FileSystem APIs - ```SanitizeEnvOptions()``` and
```NewLogger()```
Tests:
1. New unit tests
2. make check and make asan_check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6552
Reviewed By: riversand963
Differential Revision: D20592038
Pulled By: anand1976
fbshipit-source-id: c3801ad4153f96d21d5a3ae26c92ba454d1bf1f7
Summary:
There are situations when RocksDB tries to recover, but the db is in an inconsistent state due to SST files referenced in the MANIFEST being missing. In this case, previous RocksDB will just fail the recovery and return a non-ok status.
This PR enables another possibility. During recovery, RocksDB checks possible MANIFEST files, and try to recover to the most recent state without missing table file. `VersionSet::Recover()` applies version edits incrementally and "materializes" a version only when this version does not reference any missing table file. After processing the entire MANIFEST, the version created last will be the latest version.
`DBImpl::Recover()` calls `VersionSet::Recover()`. Afterwards, WAL replay will *not* be performed.
To use this capability, set `options.best_efforts_recovery = true` when opening the db. Best-efforts recovery is currently incompatible with atomic flush.
Test plan (on devserver):
```
$make check
$COMPILE_WITH_ASAN=1 make all && make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6334
Reviewed By: anand1976
Differential Revision: D19778960
Pulled By: riversand963
fbshipit-source-id: c27ea80f29bc952e7d3311ecf5ee9c54393b40a8
Summary:
When `use_direct_reads` and `use_direct_writes` are `false`, `logical_sector_size_` inside various `*File` implementations are not actually used, so `GetLogicalBlockSize` does not necessarily need to be called for `logical_sector_size_`, just set a default page size.
This is a follow up PR for https://github.com/facebook/rocksdb/pull/6457.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6522
Test Plan: make check
Reviewed By: siying
Differential Revision: D20408885
Pulled By: cheng-chang
fbshipit-source-id: f2d3808f41265237e7fa2c0be9f084f8fa97fe3d
Summary:
In Linux, when reopening DB with many SST files, profiling shows that 100% system cpu time spent for a couple of seconds for `GetLogicalBufferSize`. This slows down MyRocks' recovery time when site is down.
This PR introduces two new APIs:
1. `Env::RegisterDbPaths` and `Env::UnregisterDbPaths` lets `DB` tell the env when it starts or stops using its database directories . The `PosixFileSystem` takes this opportunity to set up a cache from database directories to the corresponding logical block sizes.
2. `LogicalBlockSizeCache` is defined only for OS_LINUX to cache the logical block sizes.
Other modifications:
1. rename `logical buffer size` to `logical block size` to be consistent with Linux terms.
2. declare `GetLogicalBlockSize` in `PosixHelper` to expose it to `PosixFileSystem`.
3. change the functions `IOError` and `IOStatus` in `env/io_posix.h` to have external linkage since they are used in other translation units too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6457
Test Plan:
1. A new unit test is added for `LogicalBlockSizeCache` in `env/io_posix_test.cc`.
2. A new integration test is added for `DB` operations related to the cache in `db/db_logical_block_size_cache_test.cc`.
`make check`
Differential Revision: D20131243
Pulled By: cheng-chang
fbshipit-source-id: 3077c50f8065c0bffb544d8f49fb10bba9408d04
Summary:
When users fail to open a DB with file lock failure, it is sometimes hard for users to debug. We now include the time the lock is acquired and the thread ID that acquired the lock, to help users debug problems like this. Default Env's thread ID is used.
Since type of lockedFiles is changed, rename it to follow naming convention too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6507
Test Plan: Add a unit test and improve an existing test to validate the case.
Differential Revision: D20378333
fbshipit-source-id: 312fe0e9733fd1d1e9969c321b90ce523cf4708a
Summary:
MultiRead tests in env_test cannot simulate the io_uring case when queries need to be submitted in multiple rounds. Add a new unit test to cover up more requests per MultiRead
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6452
Test Plan: Run it and see it pass when liburing is enabled or not enabled.
Differential Revision: D20078924
fbshipit-source-id: 6cff7fe345a4c5aa47135186e6181bf00df02b68
Summary:
Make kPageSize extern const size_t (used in draft https://github.com/facebook/rocksdb/issues/6427)
Make kLitteEndian constexpr bool
Clarify a couple of comments
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6443
Test Plan: make check, CI
Differential Revision: D20044558
Pulled By: pdillinger
fbshipit-source-id: e0c5cc13229c82726280dc0ddcba4078346b8418
Summary:
The logic that handles io_uring partial results was wrong. Fix the logic by putting it into a queue and continue reading.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6441
Test Plan: Make sure this patch fixes the application test case where the bug was discovered; in env_test, add a unit test that simulates partial results and make sure the results are still correct.
Differential Revision: D20018616
fbshipit-source-id: 5398a7e34d74c26d52aa69dfd604e93e95d99c62
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433
Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.
Differential Revision: D19977691
fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
Summary:
The DecreaseNumBgThreads test keeps failing on Windows in AppVeyor.
It fails because it depends on a timed wait for the tasks to be dequeued from the threadpool's internal queue, but within the specified time, the task might have not been scheduled onto the newly created threads.
https://github.com/facebook/rocksdb/pull/6232 tries to fix this by waiting for longer time to let the threads scheduled.
This PR tries to fix this by replacing the timed wait with a synchronization on the task's internal conditional variable.
When the number of threads increases, instead of guessing the time needed for the task to be scheduled, it directly blocks on the conditional variable until the task starts running.
But when thread number is reduced, it still does a timed wait, but this does not lead to the flakiness now, will try to remove these timed waits in a future PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6393
Test Plan: Wait to see whether AppVeyor tests pass.
Differential Revision: D19890928
Pulled By: cheng-chang
fbshipit-source-id: 4e56e4addf625c98c0876e62d9d57a6f0a156f76
Summary:
It's a minor refactoring. We have two ReadFileToString() but they are very similar. Make the one with Env argument calls the one with FS argument instead.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6366
Test Plan: Run all existing tests
Differential Revision: D19712332
fbshipit-source-id: 5ae6fabf6355938690d95cda52afd1f39e0a7823
Summary:
Some shadow warning shows up when using gcc 4.8. An example:
./utilities/blob_db/blob_compaction_filter.h: In constructor ‘rocksdb::blob_db::BlobIndexCompactionFilterFactoryBase::BlobIndexCompactionFilterFactoryBase(rocksdb::blob_db::lobDBImpl*, rocksdb::Env*, rocksdb::Statistics*)’:
./utilities/blob_db/blob_compaction_filter.h:121:7: error: declaration of ‘blob_db_impl’ shadows a member of 'this' [-Werror=shadow]
: blob_db_impl_(blob_db_impl), env_(_env), statistics_(_statistics) {}
^
Fix them.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6242
Test Plan: Build and see the warnings go away.
Differential Revision: D19217789
fbshipit-source-id: 8ef631941f23dab47a388e060adec24b72efd65e
Summary:
The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc.
This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO.
The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before.
This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection.
The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761
Differential Revision: D18868376
Pulled By: anand1976
fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
