Commit Graph

260 Commits

Author SHA1 Message Date
Akanksha Mahajan
8465cccde2 Posix API support for Async Read and Poll APIs (#9578)
Summary:
Provide support for Async Read and Poll in Posix file system using IOUring.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9578

Test Plan: In progress

Reviewed By: anand1976

Differential Revision: D34690256

Pulled By: akankshamahajan15

fbshipit-source-id: 291cbd1380a3cb904b726c34c0560d1b2ce44a2e
2022-03-10 18:28:31 -08:00
anand76
7574841aac Fix issue #9627 (#9657)
Summary:
SMB mounts do not support hard links. The ENOTSUP error code is
returned, which should be interpreted by PosixFileSystem as
IOStatus::NotSupported().

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9657

Reviewed By: mrambacher

Differential Revision: D34634783

Pulled By: anand1976

fbshipit-source-id: 0d57f5b2e6118e4c20e9ed1a293327428c3aecac
2022-03-07 11:39:31 -08:00
Peter Dillinger
ce60d0cbe5 Test refactoring for Backups+Temperatures (#9655)
Summary:
In preparation for more support for file Temperatures in BackupEngine,
this change does some test refactoring:
* Move DBTest2::BackupFileTemperature test to
BackupEngineTest::FileTemperatures, with some updates to make it work
in the new home. This test will soon be expanded for deeper backup work.
* Move FileTemperatureTestFS from db_test2.cc to db_test_util.h, to
support sharing because of above moved test, but split off the "no link"
part to the test needing it.
* Use custom FileSystems in backupable_db_test rather than custom Envs,
because going through Env file interfaces doesn't support temperatures.
* Fix RemapFileSystem to map DirFsyncOptions::renamed_new_name
parameter to FsyncWithDirOptions, which was required because this
limitation caused a crash only after moving to higher fidelity of
FileSystem interface (vs. LegacyDirectoryWrapper throwing away some
parameter details)
* `backupable_options_` -> `engine_options_` as part of the ongoing
work to get rid of the obsolete "backupable" naming.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9655

Test Plan: test code updates only

Reviewed By: jay-zhuang

Differential Revision: D34622183

Pulled By: pdillinger

fbshipit-source-id: f24b7a596a89b9e089e960f4e5d772575513e93f
2022-03-04 12:32:30 -08:00
Akanksha Mahajan
d74468e348 Update Poll and ReadAsync API in File System (#9623)
Summary:
Update the signature of Poll and ReadAsync APIs in filesystem.
Instead of unique_ptr, void** will be passed as io_handle and the delete function.
io_handle and delete function should be provided by underlying
FileSystem and its lifetime will be maintained by RocksDB. io_handle
will be deleted by RocksDB once callback is made to update the results or Poll is
called to get the results.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9623

Test Plan: Add a new unit test.

Reviewed By: anand1976

Differential Revision: D34403529

Pulled By: akankshamahajan15

fbshipit-source-id: ea185a5f4c7bec334631e4f781ea7ba4135645f0
2022-03-01 17:11:42 -08:00
mrambacher
fe9d495112 Return different Status based on ObjectRegistry::NewObject calls (#9333)
Summary:
This fix addresses https://github.com/facebook/rocksdb/issues/9299.

If attempting to create a new object via the ObjectRegistry and a factory is not found, the ObjectRegistry will return a "NotSupported" status.  This is the same behavior as previously.

If the factory is found but could not successfully create the object, an "InvalidArgument" status is returned.  If the factory returned a reason why (in the errmsg), this message will be in the returned status.

In practice, there are two options in the ConfigOptions that control how these errors are propagated:
- If "ignore_unknown_options=true", then both InvalidArgument and NotSupported status codes will be swallowed internally.  Both cases will return success
- If "ignore_unsupported_options=true", then having no factory will return success but a failing factory will return an error
- If both options are false, both cases (no and failing factory) will return errors.

In practice this likely only changes Customizable that may be partially available.  For example, the JEMallocMemoryAllocator is a built-in allocator that is registered with the system but may not be compiled in.  In this case, the status code for this allocator changed from NotSupported("JEMalloc not available") to InvalidArgumen("JEMalloc not available").  Other Customizable builtins/plugins would have the same semantics.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9333

Reviewed By: pdillinger

Differential Revision: D33517681

Pulled By: mrambacher

fbshipit-source-id: 8033052d4a4a7b88c2d9f90147b1b4467e51f6fd
2022-02-11 05:11:24 -08:00
Jay Zhuang
b69f4360ea Fix flaky test EnvPosixTestWithParam.RunMany (#9502)
Summary:
Thread-pool pops a thread function and then run the function,
which may cause thread-pool is empty but the last function is still
running.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9502

Test Plan:
`gtest-parallel ./env_test
--gtest_filter=DefaultEnvWithoutDirectIO/EnvPosixTestWithParam.RunMany/0
-r 10000 -w 1000`

Reviewed By: ajkr

Differential Revision: D34011184

Pulled By: jay-zhuang

fbshipit-source-id: 8c38bef155205bef96fd1c988dcc643a6b2ac270
2022-02-07 09:07:59 -08:00
Peter Dillinger
fd3e0f43b3 Require C++17 (#9481)
Summary:
Drop support for some old compilers by requiring C++17 standard
(or higher). See https://github.com/facebook/rocksdb/issues/9388

First modification based on this is to remove some conditional compilation in slice.h (also
better for ODR)

Also in this PR:
* Fix some Makefile formatting that seems to affect ASSERT_STATUS_CHECKED config in
some cases
* Add c_test to NON_PARALLEL_TEST in Makefile
* Fix a clang-analyze reported "potential leak" in lru_cache_test
* Better "compatibility" definition of DEFINE_uint32 for old versions of gflags
* Fix a linking problem with shared libraries in Makefile (`./random_test: error while loading shared libraries: librocksdb.so.6.29: cannot open shared object file: No such file or directory`)
* Always set ROCKSDB_SUPPORT_THREAD_LOCAL and use thread_local (from C++11)
  * TODO in later PR: clean up that obsolete flag
* Fix a cosmetic typo in c.h (https://github.com/facebook/rocksdb/issues/9488)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9481

Test Plan:
CircleCI config substantially updated.

* Upgrade to latest Ubuntu images for each release
* Generally prefer Ubuntu 20, but keep a couple Ubuntu 16 builds with oldest supported
compilers, to ensure compatibility
* Remove .circleci/cat_ignore_eagain except for Ubuntu 16 builds, because this is to work
around a kernel bug that should not affect anything but Ubuntu 16.
* Remove designated gcc-9 build, because the default linux build now uses GCC 9 from
Ubuntu 20.
* Add some `apt-key add` to fix some apt "couldn't be verified" errors
* Generally drop SKIP_LINK=1; work-around no longer needed
* Generally `add-apt-repository` before `apt-get update` as manual testing indicated the
reverse might not work.

Travis:
* Use gcc-7 by default (remove specific gcc-7 and gcc-4.8 builds)
* TODO in later PR: fix s390x "Assembler messages: Error: invalid switch -march=z14" failure

AppVeyor:
* Completely dropped because we are dropping VS2015 support and CircleCI covers
VS >= 2017

Also local testing with old gflags (out of necessity when using ROCKSDB_NO_FBCODE=1).

Reviewed By: mrambacher

Differential Revision: D33946377

Pulled By: pdillinger

fbshipit-source-id: ae077c823905b45370a26c0103ada119459da6c1
2022-02-04 17:13:10 -08:00
mrambacher
aae3093719 Introduce a CountedFileSystem for counting file operations (#9283)
Summary:
Added a CountedFileSystem that tracks a number of file operations (opens, closes, deletes, renames, flushes, syncs, fsyncs, reads, writes).    This class was based on the ReportFileOpEnv from db_bench.

This is a stepping stone PR to be able to change the SpecialEnv into a SpecialFileSystem, where several of the file varieties wish to do operation counting.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9283

Reviewed By: pdillinger

Differential Revision: D33062004

Pulled By: mrambacher

fbshipit-source-id: d0d297a7fb9c48c06cbf685e5fa755c27193b6f5
2022-02-03 15:01:23 -08:00
Yanqin Jin
50135c1bf3 Move HDFS support to separate repo (#9170)
Summary:
This PR moves HDFS support from RocksDB repo to a separate repo. The new (temporary?) repo
in this PR serves as an example before we finalize the decision on where and who to host hdfs support. At this point,
people can start from the example repo and fork.

Java/JNI is not included yet, and needs to be done later if necessary.

The goal is to include this commit in RocksDB 7.0 release.

Reference:
https://github.com/ajkr/dedupfs by ajkr

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9170

Test Plan:
Follow the instructions in https://github.com/riversand963/rocksdb-hdfs-env/blob/master/README.md. Build and run db_bench and db_stress.

make check

Reviewed By: ajkr

Differential Revision: D33751662

Pulled By: riversand963

fbshipit-source-id: 22b4db7f31762ed417a20239f5a08dcd1696244f
2022-01-24 20:23:54 -08:00
sdong
1cecd22de9 Increase wait time within EnvPosixTestWithParam.RunMany (#9413)
Summary:
We see:

[ RUN      ] ChrootEnvWithDirectIO/EnvPosixTestWithParam.RunMany/0
env/env_test.cc:464: Failure
Expected equality of these values:
  4
  cur
    Which is: 0

The suspicious is that the wait time is not long enough. Increase the wait time to 10s and allows earlier check.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9413

Test Plan: Run the test

Reviewed By: riversand963

Differential Revision: D33697715

fbshipit-source-id: 3d71715562a8cceb694b773276dd9e4e451a18bc
2022-01-24 12:50:18 -08:00
Peter Dillinger
e7ac7363b4 Add to HISTORY and minor loose ends from #9294, #9254 (#9386)
Summary:
Loose ends relate to mmap on 32-bit systems. (Testing is more
complicated when the feature was completely disabled on 32-bit.)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9386

Test Plan: CI

Reviewed By: ajkr

Differential Revision: D33590715

Pulled By: pdillinger

fbshipit-source-id: f2637036a538a552200adee65b6765fce8cae27b
2022-01-21 13:04:19 -08:00
Yanqin Jin
1a8e9f0e07 Use fcntl(F_FULLFSYNC) on OS X (#9356)
Summary:
Closing https://github.com/facebook/rocksdb/issues/5954

fsync/fdatasync on Linux:
```
(fsync/fdatasync) includes writing through or flushing a disk cache if present.
```

However, on OS X and iOS:
```
(fsync) will flush all data from the host to the drive (i.e. the "permanent storage device"),
the drive itself may not physically write the data to the platters for quite some time and it
may be written in an out-of-order sequence.
```

Solution is to use `fcntl(F_FULLFSYNC)` on OS X so that we get the same
persistence guarantee.

According to OSX man page,
```
The F_FULLFSYNC fcntl asks the drive to flush **all** buffered data to permanent storage.
```
This suggests that it will be no faster than `fsync` on Linux, since Linux, according to its man page,
```
writing through or flushing a disk cache if present
```
It means Linux may not flush **all** data from disk cache.

This is similar to bug reports/fixes in:
- golang: https://github.com/golang/go/issues/26650
- leveldb: 296de8d5b8.

Not sure if we should fallback to fsync since we break persistence contract.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9356

Reviewed By: jay-zhuang

Differential Revision: D33417416

Pulled By: riversand963

fbshipit-source-id: 475548ff9c5eaccde325e0f6842694271cbc8cb7
2022-01-18 20:23:11 -08:00
Si Ke
93b1de4f45 Enable db_test running in Centos 32 bit OS and Alpine 32 bit OS (#9294)
Summary:
Closes https://github.com/facebook/rocksdb/issues/9271

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9294

Reviewed By: riversand963, hx235

Differential Revision: D33586002

Pulled By: pdillinger

fbshipit-source-id: 3d1a2fa71023e108613ff03dbd37a5f954fc4920
2022-01-14 11:58:18 -08:00
mrambacher
1973fcba11 Restore Regex support for ObjectLibrary::Register, rename new APIs to allow old one to be deprecated in the future (#9362)
Summary:
In order to support old-style regex function registration, restored the original "Register<T>(string, Factory)" method using regular expressions.  The PatternEntry methods were left in place but renamed to AddFactory.  The goal is to allow for the deprecation of the original regex Registry method in an upcoming release.

Added modes to the PatternEntry kMatchZeroOrMore and kMatchAtLeastOne to match * or +, respectively (kMatchAtLeastOne was the original behavior).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9362

Reviewed By: pdillinger

Differential Revision: D33432562

Pulled By: mrambacher

fbshipit-source-id: ed88ab3f9a2ad0d525c7bd1692873f9bb3209d02
2022-01-11 06:33:48 -08:00
mrambacher
fe31dc53ca Make the Env class Customizable (#9293)
Summary:
Allows the Env to have options (Configurable) and loads like other Customizable classes.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9293

Reviewed By: pdillinger, zhichao-cao

Differential Revision: D33181591

Pulled By: mrambacher

fbshipit-source-id: 55e823886c654d214eda9eedd45ccdc54dac14d7
2022-01-04 16:45:49 -08:00
mrambacher
1c39b7952b Remove/Reduce use of Regex in ObjectRegistry/Library (#9264)
Summary:
Added new ObjectLibrary::Entry classes to replace/reduce the use of Regex.  For simple factories that only do name matching, there are "StringEntry" and "AltStringEntry" classes.  For classes that use some semblance of regular expressions, there is a PatternEntry class that can match a name and prefixes.  There is also a class for Customizable::IndividualId format matches.

Added tests for the new derivative classes and got all unit tests to pass.

Resolves https://github.com/facebook/rocksdb/issues/9225.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9264

Reviewed By: pdillinger

Differential Revision: D33062001

Pulled By: mrambacher

fbshipit-source-id: c2d2143bd2d38bdf522705c8280c35381b135c03
2021-12-29 07:56:23 -08:00
Peter Dillinger
0050a73a4f New stable, fixed-length cache keys (#9126)
Summary:
This change standardizes on a new 16-byte cache key format for
block cache (incl compressed and secondary) and persistent cache (but
not table cache and row cache).

The goal is a really fast cache key with practically ideal stability and
uniqueness properties without external dependencies (e.g. from FileSystem).
A fixed key size of 16 bytes should enable future optimizations to the
concurrent hash table for block cache, which is a heavy CPU user /
bottleneck, but there appears to be measurable performance improvement
even with no changes to LRUCache.

This change replaces a lot of disjointed and ugly code handling cache
keys with calls to a simple, clean new internal API (cache_key.h).
(Preserving the old cache key logic under an option would be very ugly
and likely negate the performance gain of the new approach. Complete
replacement carries some inherent risk, but I think that's acceptable
with sufficient analysis and testing.)

The scheme for encoding new cache keys is complicated but explained
in cache_key.cc.

Also: EndianSwapValue is moved to math.h to be next to other bit
operations. (Explains some new include "math.h".) ReverseBits operation
added and unit tests added to hash_test for both.

Fixes https://github.com/facebook/rocksdb/issues/7405 (presuming a root cause)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9126

Test Plan:
### Basic correctness
Several tests needed updates to work with the new functionality, mostly
because we are no longer relying on filesystem for stable cache keys
so table builders & readers need more context info to agree on cache
keys. This functionality is so core, a huge number of existing tests
exercise the cache key functionality.

### Performance
Create db with
`TEST_TMPDIR=/dev/shm ./db_bench -bloom_bits=10 -benchmarks=fillrandom -num=3000000 -partition_index_and_filters`
And test performance with
`TEST_TMPDIR=/dev/shm ./db_bench -readonly -use_existing_db -bloom_bits=10 -benchmarks=readrandom -num=3000000 -duration=30 -cache_index_and_filter_blocks -cache_size=250000 -threads=4`
using DEBUG_LEVEL=0 and simultaneous before & after runs.
Before ops/sec, avg over 100 runs: 121924
After ops/sec, avg over 100 runs: 125385 (+2.8%)

### Collision probability
I have built a tool, ./cache_bench -stress_cache_key to broadly simulate host-wide cache activity
over many months, by making some pessimistic simplifying assumptions:
* Every generated file has a cache entry for every byte offset in the file (contiguous range of cache keys)
* All of every file is cached for its entire lifetime

We use a simple table with skewed address assignment and replacement on address collision
to simulate files coming & going, with quite a variance (super-Poisson) in ages. Some output
with `./cache_bench -stress_cache_key -sck_keep_bits=40`:

```
Total cache or DBs size: 32TiB  Writing 925.926 MiB/s or 76.2939TiB/day
Multiply by 9.22337e+18 to correct for simulation losses (but still assume whole file cached)
```

These come from default settings of 2.5M files per day of 32 MB each, and
`-sck_keep_bits=40` means that to represent a single file, we are only keeping 40 bits of
the 128-bit cache key.  With file size of 2\*\*25 contiguous keys (pessimistic), our simulation
is about 2\*\*(128-40-25) or about 9 billion billion times more prone to collision than reality.

More default assumptions, relatively pessimistic:
* 100 DBs in same process (doesn't matter much)
* Re-open DB in same process (new session ID related to old session ID) on average
every 100 files generated
* Restart process (all new session IDs unrelated to old) 24 times per day

After enough data, we get a result at the end:

```
(keep 40 bits)  17 collisions after 2 x 90 days, est 10.5882 days between (9.76592e+19 corrected)
```

If we believe the (pessimistic) simulation and the mathematical generalization, we would need to run a billion machines all for 97 billion days to expect a cache key collision. To help verify that our generalization ("corrected") is robust, we can make our simulation more precise with `-sck_keep_bits=41` and `42`, which takes more running time to get enough data:

```
(keep 41 bits)  16 collisions after 4 x 90 days, est 22.5 days between (1.03763e+20 corrected)
(keep 42 bits)  19 collisions after 10 x 90 days, est 47.3684 days between (1.09224e+20 corrected)
```

The generalized prediction still holds. With the `-sck_randomize` option, we can see that we are beating "random" cache keys (except offsets still non-randomized) by a modest amount (roughly 20x less collision prone than random), which should make us reasonably comfortable even in "degenerate" cases:

```
197 collisions after 1 x 90 days, est 0.456853 days between (4.21372e+18 corrected)
```

I've run other tests to validate other conditions behave as expected, never behaving "worse than random" unless we start chopping off structured data.

Reviewed By: zhichao-cao

Differential Revision: D33171746

Pulled By: pdillinger

fbshipit-source-id: f16a57e369ed37be5e7e33525ace848d0537c88f
2021-12-16 17:15:13 -08:00
Adam Retter
c879910102 Fix fstatfs call for compilation on 32 bit systems (#9251)
Summary:
On some 32-bit systems, BTRFS_SUPER_MAGIC is unsigned while __fsword_t is signed.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9251

Reviewed By: ajkr

Differential Revision: D32961651

Pulled By: pdillinger

fbshipit-source-id: 78e85fc1336f304a21e4d5961e60957c90daed63
2021-12-08 22:01:23 -08:00
jsteemann
5384f0af6e Fix compile warnings (#9199)
Summary:
* added missing override specifiers for overriden methods
  this fixes compiler warnings emitted by g++ and clang++ when compile option `-Wsuggest-override` is turned on.
* fix compile warning with -Wmaybe-uninitialized
  g++-11 warns about a _potentially_ uninitialized variable when using `-Wmaybe_uninitialized`:
  ```
      env/env.cc: In member function ‘virtual rocksdb::Status rocksdb::Env::GetHostNameString(std::string*)’:
      env/env.cc:738:66: error: ‘hostname_buf’ may be used uninitialized [-Werror=maybe-uninitialized]
        738 |   Status s = GetHostName(hostname_buf.data(), hostname_buf.size());
            |                                                                  ^
      In file included from /usr/include/c++/11/tuple:39,
                       from /usr/include/c++/11/functional:54,
                       from ./include/rocksdb/env.h:22,
                       from env/env.cc:10:
      /usr/include/c++/11/array:176:7: note: by argument 1 of type ‘const std::array<char, 256>*’ to ‘constexpr std::array<_Tp, _Nm>::size_type std::array<_Tp, _Nm>::size() const [with _Tp = char; long unsigned int _Nm = 256]’ declared here
        176 |       size() const noexcept { return _Nm; }
            |       ^~~~
      env/env.cc:737:37: note: ‘hostname_buf’ declared here
        737 |   std::array<char, kMaxHostNameLen> hostname_buf;
  ```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9199

Reviewed By: jay-zhuang

Differential Revision: D32630703

Pulled By: pdillinger

fbshipit-source-id: 9ea3010b1105a582548e3c3c0db4475b201e4a10
2021-11-24 11:19:06 -08:00
Andrew Kryczka
9bb13c56b3 Use system-wide thread ID in info log lines (#9164)
Summary:
This makes it easier to debug with tools like `ps`. The change only
applies to builds with glibc 2.30+ and _GNU_SOURCE extensions enabled.
We could adopt it in more cases by using the syscall but this is enough
for our build.

Replaces https://github.com/facebook/rocksdb/issues/2973.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9164

Test Plan:
- ran some benchmarks and correlated logged thread IDs with those shown by `ps -L`.
- verified no noticeable regression in throughput for log heavy (more than 700k log lines and over 5k / second) scenario.

Benchmark command:

```
$ TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=filluniquerandom -compression_type=none -max_bytes_for_level_multiplier=2 -write_buffer_size=262144 -num_levels=7 -max_bytes_for_level_base=2097152 -target_file_size_base=524288 -level_compaction_dynamic_level_bytes=true -max_background_jobs=12 -num=20000000
```

Results before: 15.9MB/s, 15.8MB/s, 16.0MB/s
Results after: 16.3MB/s, 16.3MB/s, 15.8MB/s

- Rely on CI to test the fallback behavior

Reviewed By: riversand963

Differential Revision: D32399660

Pulled By: ajkr

fbshipit-source-id: c24d44fdf7782faa616ef0a0964eaca3539d9c24
2021-11-12 19:46:06 -08:00
Jay Zhuang
29102641dd Skip directory fsync for filesystem btrfs (#8903)
Summary:
Directory fsync might be expensive on btrfs and it may not be needed.
Here are 4 directory fsync cases:
1. creating a new file: dir-fsync is not needed on btrfs, as long as the
   new file itself is synced.
2. renaming a file: dir-fsync is not needed if the renamed file is
   synced. So an API `FsyncAfterFileRename(filename, ...)` is provided
   to sync the file on btrfs. By default, it just calls dir-fsync.
3. deleting files: dir-fsync is forced by set
   `IOOptions.force_dir_fsync = true`
4. renaming multiple files (like backup and checkpoint): dir-fsync is
   forced, the same as above.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8903

Test Plan: run tests on btrfs and non btrfs

Reviewed By: ajkr

Differential Revision: D30885059

Pulled By: jay-zhuang

fbshipit-source-id: dd2730b31580b0bcaedffc318a762d7dbf25de4a
2021-11-03 12:21:27 -07:00
mrambacher
f72c834eab Make FileSystem a Customizable Class (#8649)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8649

Reviewed By: zhichao-cao

Differential Revision: D32036059

Pulled By: mrambacher

fbshipit-source-id: 4f1e7557ecac52eb849b83ae02b8d7d232112295
2021-11-02 09:07:11 -07:00
Peter Dillinger
ad5325a736 Experimental support for SST unique IDs (#8990)
Summary:
* New public header unique_id.h and function GetUniqueIdFromTableProperties
which computes a universally unique identifier based on table properties
of table files from recent RocksDB versions.
* Generation of DB session IDs is refactored so that they are
guaranteed unique in the lifetime of a process running RocksDB.
(SemiStructuredUniqueIdGen, new test included.) Along with file numbers,
this enables SST unique IDs to be guaranteed unique among SSTs generated
in a single process, and "better than random" between processes.
See https://github.com/pdillinger/unique_id
* In addition to public API producing 'external' unique IDs, there is a function
for producing 'internal' unique IDs, with functions for converting between the
two. In short, the external ID is "safe" for things people might do with it, and
the internal ID enables more "power user" features for the future. Specifically,
the external ID goes through a hashing layer so that any subset of bits in the
external ID can be used as a hash of the full ID, while also preserving
uniqueness guarantees in the first 128 bits (bijective both on first 128 bits
and on full 192 bits).

Intended follow-up:
* Use the internal unique IDs in cache keys. (Avoid conflicts with https://github.com/facebook/rocksdb/issues/8912) (The file offset can be XORed into
the third 64-bit value of the unique ID.)
* Publish the external unique IDs in FileStorageInfo (https://github.com/facebook/rocksdb/issues/8968)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8990

Test Plan:
Unit tests added, and checking of unique ids in stress test.
NOTE in stress test we do not generate nearly enough files to thoroughly
stress uniqueness, but the test trims off pieces of the ID to check for
uniqueness so that we can infer (with some assumptions) stronger
properties in the aggregate.

Reviewed By: zhichao-cao, mrambacher

Differential Revision: D31582865

Pulled By: pdillinger

fbshipit-source-id: 1f620c4c86af9abe2a8d177b9ccf2ad2b9f48243
2021-10-18 23:32:01 -07:00
jsteemann
ab6755711b add IsSyncThreadSafe() override to EncryptedWritableFile (#8993)
Summary:
EncryptedWritableFile is derived from FSWritableFile, which implements
the `IsSyncThreadSafe()` function as

    bool IsSyncThreadSafe() const { return false; }

EncryptedWritableFile does not override this method from the base class,
so the `IsSyncThreadSafe()` function on an EncryptedWritableFile will
always return false.
This change adds an override of `IsSyncThreadSafe()` to
EncryptedWritableFile so that the latter will now ask its underlying
`file_` object for the thread-safety of sync operations.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8993

Reviewed By: jay-zhuang

Differential Revision: D31613123

Pulled By: ajkr

fbshipit-source-id: b18625e21a9911744eef3215c29913490e4b6001
2021-10-14 16:14:26 -07:00
mrambacher
13ae16c315 Cleanup includes in dbformat.h (#8930)
Summary:
This header file was including everything and the kitchen sink when it did not need to.  This resulted in many places including this header when they needed other pieces instead.

Cleaned up this header to only include what was needed and fixed up the remaining code to include what was now missing.

Hopefully, this sort of code hygiene cleanup will speed up the builds...

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8930

Reviewed By: pdillinger

Differential Revision: D31142788

Pulled By: mrambacher

fbshipit-source-id: 6b45de3f300750c79f751f6227dece9cfd44085d
2021-09-29 04:04:40 -07:00
mrambacher
6924869867 Make SystemClock into a Customizable Class (#8636)
Summary:
Made SystemClock into a Customizable class, complete with CreateFromString.

Cleaned up some of the existing SystemClock implementations that were redundant (NoSleep was the same as the internal one for MockEnv).

Changed MockEnv construction to allow Clock to be passed to the Memory/MockFileSystem.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8636

Reviewed By: zhichao-cao

Differential Revision: D30483360

Pulled By: mrambacher

fbshipit-source-id: cd0e3a876c39f8c98fe13374c06e8edbd5b9f2a1
2021-09-21 09:23:48 -07:00
anand76
99fe4c5005 Add a gflag for IO uring enable/disable (#8931)
Summary:
In case of IO uring bugs, we need to provide a way for users to turn it off.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8931

Test Plan: Manually run db_bench with/without the option and verify the behavior

Reviewed By: pdillinger

Differential Revision: D31040252

Pulled By: anand1976

fbshipit-source-id: 56f2537d6ac8488c9e126296d8190ad9e0158f70
2021-09-18 10:24:56 -07:00
anand76
7743f033b1 More robust checking of IO uring completion data (#8894)
Summary:
Potential bugs in the IO uring implementation can cause bad data to be returned in the completion queue. Add some checks in the PosixRandomAccessFile::MultiRead completion handling code to catch such errors and fail the entire MultiRead. Also log some diagnostic messages and stack trace.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8894

Reviewed By: siying, pdillinger

Differential Revision: D30826982

Pulled By: anand1976

fbshipit-source-id: af91815ac760e095d6cc0466cf8bd5c10167fd15
2021-09-15 12:44:43 -07:00
mrambacher
dafa584fd1 Change the File System File Wrappers to std::unique_ptr (#8618)
Summary:
This allows the wrapper classes to own the wrapped object and eliminates confusion as to ownership.  Previously, many classes implemented their own ownership solutions.  Fixes https://github.com/facebook/rocksdb/issues/8606

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8618

Reviewed By: pdillinger

Differential Revision: D30136064

Pulled By: mrambacher

fbshipit-source-id: d0bf471df8818dbb1770a86335fe98f761cca193
2021-09-13 08:46:19 -07:00
Peter Dillinger
e40b04e9fa Fix POSIX LockFile after failure to create file (#8747)
Summary:
Failure to create the lock file (e.g. out of space) could
prevent future LockFile attempts in the same process on the same file
from succeeding.

Also added DEBUG code to fail assertion if PosixFileLock is destroyed
without using UnlockFile (which is a risk because FileLock is in the
public API with virtual destructor).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8747

Test Plan: test added

Reviewed By: ajkr

Differential Revision: D30732543

Pulled By: pdillinger

fbshipit-source-id: 4c30a959566d91f778d6fad3fbbd5f3941b097c1
2021-09-07 22:41:36 -07:00
Peter Dillinger
4750421ece Replace most typedef with using= (#8751)
Summary:
Old typedef syntax is confusing

Most but not all changes with

    perl -pi -e 's/typedef (.*) ([a-zA-Z0-9_]+);/using $2 = $1;/g' list_of_files
    make format

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8751

Test Plan: existing

Reviewed By: zhichao-cao

Differential Revision: D30745277

Pulled By: pdillinger

fbshipit-source-id: 6f65f0631c3563382d43347896020413cc2366d9
2021-09-07 11:31:59 -07:00
Peter Dillinger
13ded69484 Built-in support for generating unique IDs, bug fix (#8708)
Summary:
Env::GenerateUniqueId() works fine on Windows and on POSIX
where /proc/sys/kernel/random/uuid exists. Our other implementation is
flawed and easily produces collision in a new multi-threaded test.
As we rely more heavily on DB session ID uniqueness, this becomes a
serious issue.

This change combines several individually suitable entropy sources
for reliable generation of random unique IDs, with goal of uniqueness
and portability, not cryptographic strength nor maximum speed.

Specifically:
* Moves code for getting UUIDs from the OS to port::GenerateRfcUuid
rather than in Env implementation details. Callers are now told whether
the operation fails or succeeds.
* Adds an internal API GenerateRawUniqueId for generating high-quality
128-bit unique identifiers, by combining entropy from three "tracks":
  * Lots of info from default Env like time, process id, and hostname.
  * std::random_device
  * port::GenerateRfcUuid (when working)
* Built-in implementations of Env::GenerateUniqueId() will now always
produce an RFC 4122 UUID string, either from platform-specific API or
by converting the output of GenerateRawUniqueId.

DB session IDs now use GenerateRawUniqueId while DB IDs (not as
critical) try to use port::GenerateRfcUuid but fall back on
GenerateRawUniqueId with conversion to an RFC 4122 UUID.

GenerateRawUniqueId is declared and defined under env/ rather than util/
or even port/ because of the Env dependency.

Likely follow-up: enhance GenerateRawUniqueId to be faster after the
first call and to guarantee uniqueness within the lifetime of a single
process (imparting the same property onto DB session IDs).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8708

Test Plan:
A new mini-stress test in env_test checks the various public
and internal APIs for uniqueness, including each track of
GenerateRawUniqueId individually. We can't hope to verify anywhere close
to 128 bits of entropy, but it can at least detect flaws as bad as the
old code. Serial execution of the new tests takes about 350 ms on
my machine.

Reviewed By: zhichao-cao, mrambacher

Differential Revision: D30563780

Pulled By: pdillinger

fbshipit-source-id: de4c9ff4b2f581cf784fcedb5f39f16e5185c364
2021-08-30 15:20:41 -07:00
Merlin Mao
f58d276764 Make TraceRecord and Replayer public (#8611)
Summary:
New public interfaces:
`TraceRecord` and `TraceRecord::Handler`, available in "rocksdb/trace_record.h".
`Replayer`, available in `rocksdb/utilities/replayer.h`.

User can use `DB::NewDefaultReplayer()` to create a Replayer to auto/manual replay a trace file.

Unit tests:
- `./db_test2 --gtest_filter="DBTest2.TraceAndReplay"`: Updated with the internal API changes.
- `./db_test2 --gtest_filter="DBTest2.TraceAndManualReplay"`: New for manual replay.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8611

Reviewed By: ajkr

Differential Revision: D30266329

Pulled By: autopear

fbshipit-source-id: 1ecb3cbbedae0f6a67c18f0cc82e002b4d81b6f8
2021-08-11 19:32:46 -07:00
Mark Rambacher
42ba60b3ba Make EncryptionProvider and BlockCipher into Customizable objects (#8354)
Summary:
Made the EncryptionProvider and BlockCipher classes inherit from Customizable.  Added/fixed the CreateFromString method to these classes to create instances from builtin or registered classes.  Added tests to verify that instances can be registered and retrieved as appropriate.

Added the ability to configure the builtin (CTR, ROT13) classes from configurable properties.  Added the appropriate tests.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8354

Reviewed By: zhichao-cao

Differential Revision: D29558949

Pulled By: mrambacher

fbshipit-source-id: c20286b32d179777e060f51a58943e9b0cf81d04
2021-07-16 07:58:51 -07:00
Peter Dillinger
a53d6d25e0 Improve support for valgrind error on reachable (#8503)
Summary:
MyRocks apparently uses valgrind to check for unreachable
unfreed data, which is stricter than our valgrind checks. Internal ref:
D29257815

This patch adds valgrind support to STATIC_AVOID_DESTRUCTION so that it's
not reported with those stricter checks.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8503

Test Plan:
make valgrind_test
Also, with modified VALGRIND_OPTS (see Makefile), more kinds of
failures seen before than after this commit.

Reviewed By: ajkr, yizhang82

Differential Revision: D29597784

Pulled By: pdillinger

fbshipit-source-id: 360de157a176aec4d1be99ca20d160ecd47c0873
2021-07-12 17:00:27 -07:00
mrambacher
281ac9c89e Add CreateFrom methods to Env/FileSystem (#8174)
Summary:
- Added CreateFromString method to Env and FilesSystem to replace LoadEnv/Load.  This method/signature is a precursor to making these classes extend Customizable.

- Added CreateFromSystem to Env.  This method standardizes creating an Env from the environment variables.  Previously, some places would check TEST_ENV_URI and others would also check TEST_FS_URI.  Now the code is more command/standardized.

- Added CreateFromFlags to Env.  These method allows Env to be create from string options (such as GFLAGS options) in a more standard way.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8174

Reviewed By: zhichao-cao

Differential Revision: D28999603

Pulled By: mrambacher

fbshipit-source-id: 88e6911e7e91f908458a7fe10a20e93ecbc275fb
2021-06-15 03:43:48 -07:00
matthewvon
5a2b4ed671 BugFix: fs_posix.cc GetFreeSpace uses wrong value non-root users (#8370)
Summary:
fs_posix.cc GetFreeSpace() calculates free space based upon a call to statvfs().  However, there are two extremely different values in statvfs's returned structure:  f_bfree which is free space for root and f_bavail which is free space for non-root users.  The existing code uses f_bfree.  Many disks have 5 to 10% of the total disk space reserved for root only.  Therefore GetFreeSpace() does not realize that non-root users may not have storage available.

This PR detects whether the effective posix user is root or not, then selects the appropriate available space value.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8370

Reviewed By: mrambacher

Differential Revision: D29032710

Pulled By: jay-zhuang

fbshipit-source-id: 57feba34ed035615a479956d28f98d85735281c0
2021-06-10 11:11:54 -07:00
sdong
871a2cb292 Fix test issue in new env_test tests (#8319)
Summary:
The two new tests added to env_test don't clear sync points, so if tests are run in continuous mode, rather than parallel mode, the next test will trigger previous sync point and fail. Fix it.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8319

Test Plan: Run the tests in continuous mode which used to fail and see them passing.

Reviewed By: pdillinger

Differential Revision: D28542562

fbshipit-source-id: 4052d487635188fe68a2a9df4b03d97b23f96720
2021-05-19 10:59:02 -07:00
sdong
ce0fc71adf Minor improvements in env_test (#8317)
Summary:
Fix typo in comments in env_test and add PermitUncheckedError() to two statuses.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8317

Reviewed By: jay-zhuang

Differential Revision: D28525093

fbshipit-source-id: 7a1ed3e45b6f500b8d2ae19fa339c9368111e922
2021-05-19 10:28:08 -07:00
sdong
60e5af83c1 Handle return code by io_uring_submit_and_wait() and io_uring_wait_cqe() (#8311)
Summary:
Right now return codes by io_uring_submit_and_wait() and io_uring_wait_cqe() are not handled. It is not the good practice. Although these two functions are not supposed to return non-0 values in normal exeuction, people suspect that they might return non-0 value when an interruption happens, and the code might cause hanging.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8311

Test Plan: Make sure at least normal test cases still pass.

Reviewed By: anand1976

Differential Revision: D28500828

fbshipit-source-id: 8a76cea9cafbd041102e0b6a8eef9d0bfed7c211
2021-05-18 16:09:14 -07:00
sdong
e19908cba6 Refactor kill point (#8241)
Summary:
Refactor kill point to one single class, rather than several extern variables. The intention was to drop unflushed data before killing to simulate some job, and I tried to a pointer to fault ingestion fs to the killing class, but it ended up with harder than I thought. Perhaps we'll need to do this in another way. But I thought the refactoring itself is good so I send it out.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8241

Test Plan: make release and run crash test for a while.

Reviewed By: anand1976

Differential Revision: D28078486

fbshipit-source-id: f9182c1455f52e6851c13f88a21bade63bcec45f
2021-05-05 15:50:29 -07:00
Jay Zhuang
a89740fbc6 Fix unittest no space issue (#8204)
Summary:
Unittest reports no space from time to time, which can be reproduced on a small memory machine with SHM. It's caused by large WAL files generated during the test, which is preallocated, but didn't truncate during close(). Adding the missing APIs to set preallocation.
It added arm test as nightly build, as the test runs more than 1 hour.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8204

Test Plan: test on small memory arm machine

Reviewed By: mrambacher

Differential Revision: D27873145

Pulled By: jay-zhuang

fbshipit-source-id: f797c429d6bc13cbcc673bc03fcc72adda55f506
2021-04-20 08:42:28 -07:00
Akanksha Mahajan
d52b520d51 Integrated BlobDB for backup/restore support (#8129)
Summary:
Add support for blob files for backup/restore like table files.
    Since DB session ID is currently not supported for blob files (there is no place to store it in
    the header), so for blob files uses the
    kLegacyCrc32cAndFileSize naming scheme even if
    share_files_with_checksum_naming is set to kUseDbSessionId.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8129

Test Plan: Add new test units

Reviewed By: ltamasi

Differential Revision: D27408510

Pulled By: akankshamahajan15

fbshipit-source-id: b27434d189a639ef3e6ad165c61a143a2daaf06e
2021-04-07 13:38:54 -07:00
Peter Dillinger
35af0433cf Fix crash test with backup as read-only DB (#8161)
Summary:
Forgot to re-test crash test after adding read-only filesystem
enforcement to https://github.com/facebook/rocksdb/issues/8142. The problem is ReadOnlyFileSystem would reject
CreateDirIfMissing whenever DBOptions::create_if_missing=true. The fix
that is better for users is to allow CreateDirIfMissing in
ReadOnlyFileSystem if the directory exists, so that they don't cause a
failure on using create_if_missing with opening backups as read-only
DBs. Added this option test to the unit test (in addition to being in the
crash test).

Also fixed a couple of lints.

And some better messaging from 'make format' so that when you run it
with uncommitted changes, it's clear that it's only checking the
uncommitted changes.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8161

Test Plan: local blackbox_crash_test with amplified backup_one_in

Reviewed By: ajkr

Differential Revision: D27614409

Pulled By: pdillinger

fbshipit-source-id: 63ccb626c7e34c200d61c6bca2a8f60da9015179
2021-04-06 23:31:51 -07:00
Peter Dillinger
879357fdb0 Make backups openable as read-only DBs (#8142)
Summary:
A current limitation of backups is that you don't know the
exact database state of when the backup was taken. With this new
feature, you can at least inspect the backup's DB state without
restoring it by opening it as a read-only DB.

Rather than add something like OpenAsReadOnlyDB to the BackupEngine API,
which would inhibit opening stackable DB implementations read-only
(if/when their APIs support it), we instead provide a DB name and Env
that can be used to open as a read-only DB.

Possible follow-up work:

* Add a version of GetBackupInfo for a single backup.
* Let CreateNewBackup return the BackupID of the newly-created backup.

Implementation details:

Refactored ChrootFileSystem to split off new base class RemapFileSystem,
which allows more general remapping of files. We use this base class to
implement BackupEngineImpl::RemapSharedFileSystem.

To minimize API impact, I decided to just add these fields `name_for_open`
and `env_for_open` to those set by GetBackupInfo when
include_file_details=true. Creating the RemapSharedFileSystem adds a bit
to the memory consumption, perhaps unnecessarily in some cases, but this
has been mitigated by (a) only initialize the RemapSharedFileSystem
lazily when GetBackupInfo with include_file_details=true is called, and
(b) using the existing `shared_ptr<FileInfo>` objects to hold most of the
mapping data.

To enhance API safety, RemapSharedFileSystem is wrapped by new
ReadOnlyFileSystem which rejects any attempts to write. This uncovered a
couple of places in which DB::OpenForReadOnly would write to the
filesystem, so I fixed these. Added a release note because this affects
logging.

Additional minor refactoring in backupable_db.cc to support the new
functionality.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8142

Test Plan:
new test (run with ASAN and UBSAN), added to stress test and
ran it for a while with amplified backup_one_in

Reviewed By: ajkr

Differential Revision: D27535408

Pulled By: pdillinger

fbshipit-source-id: 04666d310aa0261ef6b2385c43ca793ce1dfd148
2021-04-06 14:37:53 -07:00
Akanksha Mahajan
689b13e639 Add request_id in IODebugContext. (#8045)
Summary:
Add request_id in IODebugContext which will be populated by
    underlying FileSystem for IOTracing purposes. Update IOTracer to trace
    request_id in the tracing records. Provided API
    IODebugContext::SetRequestId which will set the request_id and enable
    tracing for request_id. The API hides the implementation and underlying
    file system needs to call this API directly.

Update DB::StartIOTrace API and remove redundant Env* from the
    argument as its not used and DB already has Env that is passed down to
    IOTracer.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8045

Test Plan: Update unit test.

Differential Revision: D26899871

Pulled By: akankshamahajan15

fbshipit-source-id: 56adef52ee5af0fb3060b607c3af1ec01635fa2b
2021-04-01 13:14:51 -07:00
Imanol-Mikel Barba Sabariego
04191e1c5d Adding safer permissions to PosixFilesystem::NewLogger (#8106)
Summary:
We have observed rocksdb databases creating info log files with world-writeable permissions.

The reason why the file is created like so is because stdio streams opened with fopen calls use mode 0666, and while normally most systems have a umask of 022, in some occasions (for instance, while running daemons), you may find that the application is running with a less restrictive umask. The result is that when opening the DB, the LOG file would be created with world-writeable perms:

```
$ ls -lh db/
total 6.4M
-rw-r--r-- 1 ibarba users  115 Mar 24 17:41 000004.log
-rw-r--r-- 1 ibarba users   16 Mar 24 17:41 CURRENT
-rw-r--r-- 1 ibarba users   37 Mar 24 17:41 IDENTITY
-rw-r--r-- 1 ibarba users    0 Mar 24 17:41 LOCK
-rw-rw-r-- 1 ibarba users 114K Mar 24 17:41 LOG
-rw-r--r-- 1 ibarba users  514 Mar 24 17:41 MANIFEST-000003
-rw-r--r-- 1 ibarba users  31K Mar 24 17:41 OPTIONS-000018
-rw-r--r-- 1 ibarba users  31K Mar 24 17:41 OPTIONS-000020
```

This diff replaces the fopen call with a regular open() call restricting mode, and then using fdopen to associate an stdio stream with that file descriptor. Resulting in the following files being created:

```
-rw-r--r-- 1 ibarba users   58 Mar 24 18:16 000004.log
-rw-r--r-- 1 ibarba users   16 Mar 24 18:16 CURRENT
-rw-r--r-- 1 ibarba users   37 Mar 24 18:16 IDENTITY
-rw-r--r-- 1 ibarba users    0 Mar 24 18:16 LOCK
-rw-r--r-- 1 ibarba users 111K Mar 24 18:16 LOG
-rw-r--r-- 1 ibarba users  514 Mar 24 18:16 MANIFEST-000003
-rw-r--r-- 1 ibarba users  31K Mar 24 18:16 OPTIONS-000018
-rw-r--r-- 1 ibarba users  31K Mar 24 18:16 OPTIONS-000020
```

With the correct permissions

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8106

Reviewed By: akankshamahajan15

Differential Revision: D27415377

Pulled By: mrambacher

fbshipit-source-id: 97ac6c215700a7ea306f4a1fdf9fcf64a3cbb202
2021-03-29 20:47:21 -07:00
anand76
7d7f14480e Always truncate the latest WAL file on DB Open (#8122)
Summary:
Currently, we only truncate the latest alive WAL files when the DB is opened. If the latest WAL file is empty or was flushed during Open, its not truncated since the file will be deleted later on in the Open path. However, before deletion, a new WAL file is created, and if the process crash loops between the new WAL file creation and deletion of the old WAL file, the preallocated space will keep accumulating and eventually use up all disk space. To prevent this, always truncate the latest WAL file, even if its empty or the data was flushed.

Tests:
Add unit tests to db_wal_test

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8122

Reviewed By: riversand963

Differential Revision: D27366132

Pulled By: anand1976

fbshipit-source-id: f923cc03ef033ccb32b140d36c6a63a8152f0e8e
2021-03-28 10:00:08 -07:00
Jay Zhuang
ce6de862c1 Avoid checking errno on success call (#8119)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8119

Reviewed By: sushilpa

Differential Revision: D27365407

Pulled By: jay-zhuang

fbshipit-source-id: 327c09bf76834ce0be4287680640adc8b88bcec2
2021-03-26 18:46:38 -07:00
Jay Zhuang
45c65d6dcf Use thread-safe strerror_r() to get error message (#8087)
Summary:
`strerror()` is not thread-safe, using `strerror_r()` instead. The API could be different on the different platforms, used the code from 0deef031cb/folly/String.cpp (L457)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8087

Reviewed By: mrambacher

Differential Revision: D27267151

Pulled By: jay-zhuang

fbshipit-source-id: 4b8856d1ec069d5f239b764750682c56e5be9ddb
2021-03-24 23:07:27 -07:00