Summary:
* **macOS version:** 10.15.2 (Catalina)
* **XCode/Clang version:** Apple clang version 11.0.0 (clang-1100.0.33.16)

Before this bugfix the error generated is:

```
In file included from ./util/compression.h:23:
./snappy-1.1.7/snappy.h:76:59: error: unknown type name 'string'; did you mean 'std::string'?
  size_t Compress(const char* input, size_t input_length, string* output);
                                                          ^~~~~~
                                                          std::string
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/iosfwd:211:65: note: 'std::string' declared here
typedef basic_string<char, char_traits<char>, allocator<char> > string;
                                                                ^
In file included from db/builder.cc:10:
In file included from ./db/builder.h:12:
In file included from ./db/range_tombstone_fragmenter.h:15:
In file included from ./db/pinned_iterators_manager.h:12:
In file included from ./table/internal_iterator.h:13:
In file included from ./table/format.h:25:
In file included from ./options/cf_options.h:14:
In file included from ./util/compression.h:23:
./snappy-1.1.7/snappy.h:85:19: error: unknown type name 'string'; did you mean 'std::string'?
                  string* uncompressed);
                  ^~~~~~
                  std::string
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/iosfwd:211:65: note: 'std::string' declared here
typedef basic_string<char, char_traits<char>, allocator<char> > string;
                                                                ^
2 errors generated.
make: *** [jls/db/builder.o] Error 1
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6496

Differential Revision: D20389254

Pulled By: pdillinger

fbshipit-source-id: 2864245c8d0dba7b2ab81294241a62f2adf02e20

Summary:
It's never too soon to refactor something. The patch splits the recently
introduced (`VersionEdit` related) `BlobFileState` into two classes
`BlobFileAddition` and `BlobFileGarbage`. The idea is that once blob files
are closed, they are immutable, and the only thing that changes is the
amount of garbage in them. In the new design, `BlobFileAddition` contains
the immutable attributes (currently, the count and total size of all blobs, checksum
method, and checksum value), while `BlobFileGarbage` contains the mutable
GC-related information elements (count and total size of garbage blobs). This is a
better fit for the GC logic and is more consistent with how SST files are handled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6502

Test Plan: `make check`

Differential Revision: D20348352

Pulled By: ltamasi

fbshipit-source-id: ff93f0121e80ab15e0e0a6525ba0d6af16a0e008

Summary:
In the current code base, we can use FaultInjectionTestEnv to simulate the env issue such as file write/read errors, which are used in most of the test. The PR https://github.com/facebook/rocksdb/issues/5761 introduce the File System as a new Env API. This PR implement the FaultInjectionTestFS, which can be used to simulate when File System has issues such as IO error. user can specify any IOStatus error as input, such that FS corresponding actions will return certain error to the caller.

A set of ErrorHandlerFSTests are introduced for testing
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6414

Test Plan: pass make asan_check, pass error_handler_fs_test.

Differential Revision: D20252421

Pulled By: zhichao-cao

fbshipit-source-id: e922038f8ce7e6d1da329fd0bba7283c4b779a21

Summary:
Found from Debian's "Lintian" program
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6464

Differential Revision: D20162862

Pulled By: zhichao-cao

fbshipit-source-id: 06941ee2437b038b2b8045becbe9d2c6fbff3e12

Summary:
BlobDB currently does not keep track of blob files: no records are written to
the manifest when a blob file is added or removed, and upon opening a database,
the list of blob files is populated simply based on the contents of the blob directory.
This means that lost blob files cannot be detected at the moment. We plan to solve
this issue by making blob files a part of `Version`; as a first step, this patch makes
it possible to store information about blob files in `VersionEdit`. Currently, this information
includes blob file number, total number and size of all blobs, and total number and size
of garbage blobs. However, the format is extensible: new fields can be added in
both a forward compatible and a forward incompatible manner if needed (similarly
to `kNewFile4`).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6416

Test Plan: `make check`

Differential Revision: D19894234

Pulled By: ltamasi

fbshipit-source-id: f9753e1f2aedf6dadb70c09b345207cb9c58c329

Summary:
Add a utility class `Defer` to defer the execution of a function until the Defer object goes out of scope.
Used in VersionSet:: ProcessManifestWrites as an example.
The inline comments for class `Defer` have more details.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6382

Test Plan: `make defer_test version_set_test && ./defer_test && ./version_set_test`

Differential Revision: D19797538

Pulled By: cheng-chang

fbshipit-source-id: b1a9b7306e4fd4f48ec2ab55783caa561a315f0f

Summary:
It's logically correct for PinnableSlice to support move semantics to transfer ownership of the pinned memory region. This PR adds both move constructor and move assignment to PinnableSlice.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6374

Test Plan:
A set of unit tests for the move semantics are added in slice_test.
So `make slice_test && ./slice_test`.

Differential Revision: D19739254

Pulled By: cheng-chang

fbshipit-source-id: f898bd811bb05b2d87384ec58b645e9915e8e0b1

Summary:
I set up a mirror of our Java deps on github so we can download
them through github URLs rather than maven.org, which is proving
terribly unreliable from Travis builds.

Also sanitized calls to curl, so they are easier to read and
appropriately fail on download failure.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6348

Test Plan: CI

Differential Revision: D19633621

Pulled By: pdillinger

fbshipit-source-id: 7eb3f730953db2ead758dc94039c040f406790f3

Summary:
Both changes are related to RocksJava:

1. Allow dependencies that are already present on the host system due to Maven to be reused in Docker builds.

2. Extend the `make clean-not-downloaded` target to RocksJava, so that libraries needed as dependencies for the test suite are not deleted and re-downloaded unnecessarily.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6318

Differential Revision: D19608742

Pulled By: pdillinger

fbshipit-source-id: 25e25649e3e3212b537ac4512b40e2e53dc02ae7

Summary:
Clang analyzer was falsely reporting on use of txn=nullptr.
Added a new const variable so that it can properly prune impossible
control flows.

Also, 'make analyze' previously required setting USE_CLANG=1 as an
environment variable, not a make variable, or else compilation errors
like

g++: error: unrecognized command line option ‘-Wshorten-64-to-32’

Now USE_CLANG is not required for 'make analyze' (it's implied) and you
can do an incremental analysis (recompile what has changed) with
'USE_CLANG=1 make analyze_incremental'
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6244

Test Plan: 'make -j24 analyze', 'make crash_test'

Differential Revision: D19225950

Pulled By: pdillinger

fbshipit-source-id: 14f4039aa552228826a2de62b2671450e0fed3cb

Summary:
Currently, db_stress performs verification by calling `VerifyDb()` at the end of test and optionally before tests start. In case of corruption or incorrect result, it will be too late. This PR adds more verification in two ways.
1. For cf consistency test, each test thread takes a snapshot and verifies every N ops. N is configurable via `-verify_db_one_in`. This option is not supported in other stress tests.
2. For cf consistency test, we use another background thread in which a secondary instance periodically tails the primary (interval is configurable). We verify the secondary. Once an error is detected, we terminate the test and report. This does not affect other stress tests.

Test plan (devserver)
```
$./db_stress -test_cf_consistency -verify_db_one_in=0 -ops_per_thread=100000 -continuous_verification_interval=100
$./db_stress -test_cf_consistency -verify_db_one_in=1000 -ops_per_thread=10000 -continuous_verification_interval=0
$make crash_test
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6173

Differential Revision: D19047367

Pulled By: riversand963

fbshipit-source-id: aeed584ad71f9310c111445f34975e5ab47a0615

Summary:
Adds a python script to syntax check all python files in the
repository and report any errors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6209

Test Plan:
'make check' with and without seeded syntax errors. Also look
for "No syntax errors in 34 .py files" on success, and in java_test CI output

Differential Revision: D19166756

Pulled By: pdillinger

fbshipit-source-id: 537df464b767260d66810b4cf4c9808a026c58a4

Summary:
And clean up related code, especially in stress test.

(More clean up of db_stress_test_base.cc coming after this.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6154

Test Plan: make check, make blackbox_crash_test for a bit

Differential Revision: D18938180

Pulled By: pdillinger

fbshipit-source-id: 524d27621b8dbb25f6dff40f1081e7c00630357e

Summary:
Start daily crash tests with use_txn flag.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6155

Differential Revision: D18943630

Pulled By: maysamyabandeh

fbshipit-source-id: eea99a6ffd5f57fb9651f6ca7dab8fbf70379c87

Summary:
Error message when running `make` on Mac OS with master branch (v6.6.0):
```
$ make
$DEBUG_LEVEL is 1
Makefile:168: Warning: Compiling in debug mode. Don't use the resulting binary in production
third-party/folly/folly/synchronization/WaitOptions.cpp:6:10: fatal error: 'folly/synchronization/WaitOptions.h' file not found
#include <folly/synchronization/WaitOptions.h>
         ^
1 error generated.
third-party/folly/folly/synchronization/ParkingLot.cpp:6:10: fatal error: 'folly/synchronization/ParkingLot.h' file not found
#include <folly/synchronization/ParkingLot.h>
         ^
1 error generated.
third-party/folly/folly/synchronization/DistributedMutex.cpp:6:10: fatal error: 'folly/synchronization/DistributedMutex.h' file not found
#include <folly/synchronization/DistributedMutex.h>
         ^
1 error generated.
third-party/folly/folly/synchronization/AtomicNotification.cpp:6:10: fatal error: 'folly/synchronization/AtomicNotification.h' file not found
#include <folly/synchronization/AtomicNotification.h>
         ^
1 error generated.
third-party/folly/folly/detail/Futex.cpp:6:10: fatal error: 'folly/detail/Futex.h' file not found
#include <folly/detail/Futex.h>
         ^
1 error generated.
  GEN      util/build_version.cc
$DEBUG_LEVEL is 1
Makefile:168: Warning: Compiling in debug mode. Don't use the resulting binary in production
third-party/folly/folly/synchronization/WaitOptions.cpp:6:10: fatal error: 'folly/synchronization/WaitOptions.h' file not found
#include <folly/synchronization/WaitOptions.h>
         ^
1 error generated.
third-party/folly/folly/synchronization/ParkingLot.cpp:6:10: fatal error: 'folly/synchronization/ParkingLot.h' file not found
#include <folly/synchronization/ParkingLot.h>
         ^
1 error generated.
third-party/folly/folly/synchronization/DistributedMutex.cpp:6:10: fatal error: 'folly/synchronization/DistributedMutex.h' file not found
#include <folly/synchronization/DistributedMutex.h>
         ^
1 error generated.
third-party/folly/folly/synchronization/AtomicNotification.cpp:6:10: fatal error: 'folly/synchronization/AtomicNotification.h' file not found
#include <folly/synchronization/AtomicNotification.h>
         ^
1 error generated.
third-party/folly/folly/detail/Futex.cpp:6:10: fatal error: 'folly/detail/Futex.h' file not found
#include <folly/detail/Futex.h>
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6145

Differential Revision: D18910812

fbshipit-source-id: 5a4475466c2d0601657831a0b48d34316b2f0816

Summary:
db_stress_tool.cc now is a giant file. In order to main it easier to improve and maintain, break it down to multiple source files.
Most classes are turned into their own files. Separate .h and .cc files are created for gflag definiations. Another .h and .cc files are created for some common functions. Some test execution logic that is only loosely related to class StressTest is moved to db_stress_driver.h and db_stress_driver.cc. All the files are located under db_stress_tool/. The directory name is created as such because if we end it with either stress or test, .gitignore will ignore any file under it and makes it prone to issues in developements.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6134

Test Plan: Build under GCC7 with and without LITE on using GNU Make. Build with GCC 4.8. Build with cmake with -DWITH_TOOL=1

Differential Revision: D18876064

fbshipit-source-id: b25d0a7451840f31ac0f5ebb0068785f783fdf7d

Summary:
Before this fix, `make all` will emit full compilation command when building
object files in the third-party/folly directory even if default verbosity is
0 (AM_DEFAULT_VERBOSITY).

Test Plan (devserver):
```
$make all | tee build.log
$make check
```
Check build.log to verify.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6120

Differential Revision: D18795621

Pulled By: riversand963

fbshipit-source-id: 04641a8359cd4fd55034e6e797ed85de29ee2fe2

Summary:
Add the jni library for musl-libc, specifically for incorporating into Alpine based docker images. The classifier is `musl64`.

I have signed the CLA electronically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3143

Differential Revision: D18719372

fbshipit-source-id: 6189d149310b6436d6def7d808566b0234b23313

Summary:
**NOTE**: This also needs to be back-ported to be 6.4.6

Fix a regression introduced in f2bf0b2d by https://github.com/facebook/rocksdb/pull/5674 whereby the compiled library would get the wrong name on PPC64LE platforms.

On PPC64LE, the regression caused the library to be named `librocksdbjni-linux64.so` instead of `librocksdbjni-linux-ppc64le.so`.

This PR corrects the name back to `librocksdbjni-linux-ppc64le.so` and also corrects the ordering of conditional arguments in the Makefile to match the expected order as defined in the documentation for Make.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6080

Differential Revision: D18710351

fbshipit-source-id: d4db87ef378263b57de7f9edce1b7d15644cf9de

Summary:
* We can reuse downloaded 3rd-party libraries
* We can isolate the build to a Docker volume. This is useful for investigating failed builds, as we can examine the volume by assigning it a name during the build.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6079

Differential Revision: D18710263

fbshipit-source-id: 93f456ba44b49e48941c43b0c4d53995ecc1f404

Summary:
* LZ4 1.8.3 -> 1.9.2
* ZSTD 1.4.0 -> 1.4.4
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6084

Differential Revision: D18710224

fbshipit-source-id: a461ef19a473d3480acdc027f627ec3048730692

Summary:
Had complications with LITE build and valgrind test.
Reverts/fixes small parts of PR https://github.com/facebook/rocksdb/issues/6007
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6036

Test Plan:
make LITE=1 all check
and
ROCKSDB_VALGRIND_RUN=1 DISABLE_JEMALLOC=1 make -j24 db_bloom_filter_test && ROCKSDB_VALGRIND_RUN=1 DISABLE_JEMALLOC=1 ./db_bloom_filter_test

Differential Revision: D18512238

Pulled By: pdillinger

fbshipit-source-id: 37213cf0d309edf11c483fb4b2fb6c02c2cf2b28

Summary:
Adds an improved, replacement Bloom filter implementation (FastLocalBloom) for full and partitioned filters in the block-based table. This replacement is faster and more accurate, especially for high bits per key or millions of keys in a single filter.

Speed

The improved speed, at least on recent x86_64, comes from
* Using fastrange instead of modulo (%)
* Using our new hash function (XXH3 preview, added in a previous commit), which is much faster for large keys and only *slightly* slower on keys around 12 bytes if hashing the same size many thousands of times in a row.
* Optimizing the Bloom filter queries with AVX2 SIMD operations. (Added AVX2 to the USE_SSE=1 build.) Careful design was required to support (a) SIMD-optimized queries, (b) compatible non-SIMD code that's simple and efficient, (c) flexible choice of number of probes, and (d) essentially maximized accuracy for a cache-local Bloom filter. Probes are made eight at a time, so any number of probes up to 8 is the same speed, then up to 16, etc.
* Prefetching cache lines when building the filter. Although this optimization could be applied to the old structure as well, it seems to balance out the small added cost of accumulating 64 bit hashes for adding to the filter rather than 32 bit hashes.

Here's nominal speed data from filter_bench (200MB in filters, about 10k keys each, 10 bits filter data / key, 6 probes, avg key size 24 bytes, includes hashing time) on Skylake DE (relatively low clock speed):

$ ./filter_bench -quick -impl=2 -net_includes_hashing # New Bloom filter
Build avg ns/key: 47.7135
Mixed inside/outside queries...
  Single filter net ns/op: 26.2825
  Random filter net ns/op: 150.459
    Average FP rate %: 0.954651
$ ./filter_bench -quick -impl=0 -net_includes_hashing # Old Bloom filter
Build avg ns/key: 47.2245
Mixed inside/outside queries...
  Single filter net ns/op: 63.2978
  Random filter net ns/op: 188.038
    Average FP rate %: 1.13823

Similar build time but dramatically faster query times on hot data (63 ns to 26 ns), and somewhat faster on stale data (188 ns to 150 ns). Performance differences on batched and skewed query loads are between these extremes as expected.

The only other interesting thing about speed is "inside" (query key was added to filter) vs. "outside" (query key was not added to filter) query times. The non-SIMD implementations are substantially slower when most queries are "outside" vs. "inside". This goes against what one might expect or would have observed years ago, as "outside" queries only need about two probes on average, due to short-circuiting, while "inside" always have num_probes (say 6). The problem is probably the nastily unpredictable branch. The SIMD implementation has few branches (very predictable) and has pretty consistent running time regardless of query outcome.

Accuracy

The generally improved accuracy (re: Issue https://github.com/facebook/rocksdb/issues/5857) comes from a better design for probing indices
within a cache line (re: Issue https://github.com/facebook/rocksdb/issues/4120) and improved accuracy for millions of keys in a single filter from using a 64-bit hash function (XXH3p). Design details in code comments.

Accuracy data (generalizes, except old impl gets worse with millions of keys):
Memory bits per key: FP rate percent old impl -> FP rate percent new impl
6: 5.70953 -> 5.69888
8: 2.45766 -> 2.29709
10: 1.13977 -> 0.959254
12: 0.662498 -> 0.411593
16: 0.353023 -> 0.0873754
24: 0.261552 -> 0.0060971
50: 0.225453 -> ~0.00003 (less than 1 in a million queries are FP)

Fixes https://github.com/facebook/rocksdb/issues/5857
Fixes https://github.com/facebook/rocksdb/issues/4120

Unlike the old implementation, this implementation has a fixed cache line size (64 bytes). At 10 bits per key, the accuracy of this new implementation is very close to the old implementation with 128-byte cache line size. If there's sufficient demand, this implementation could be generalized.

Compatibility

Although old releases would see the new structure as corrupt filter data and read the table as if there's no filter, we've decided only to enable the new Bloom filter with new format_version=5. This provides a smooth path for automatic adoption over time, with an option for early opt-in.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6007

Test Plan: filter_bench has been used thoroughly to validate speed, accuracy, and correctness. Unit tests have been carefully updated to exercise new and old implementations, as well as the logic to select an implementation based on context (format_version).

Differential Revision: D18294749

Pulled By: pdillinger

fbshipit-source-id: d44c9db3696e4d0a17caaec47075b7755c262c5f

Summary:
From bzip2's official [download page](http://www.bzip.org/downloads.html), we could download it from sourceforge. This source would be more credible than previous web archive.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5995

Differential Revision: D18377662

fbshipit-source-id: e8353f83d5d6ea6067f78208b7bfb7f0d5b49c05

Summary:
include db_stress_tool in rocksdb tools lib

Test Plan (on devserver):
```
$make db_stress
$./db_stress
$make all && make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5950

Differential Revision: D18044399

Pulled By: riversand963

fbshipit-source-id: 895585abbbdfd8b954965921dba4b1400b7af1b1

Summary:
expose db stress test by providing db_stress_tool.h in public header.
This PR does the following:
- adds a new header, db_stress_tool.h, in include/rocksdb/
- renames db_stress.cc to db_stress_tool.cc
- adds a db_stress.cc which simply invokes a test function.
- update Makefile accordingly.

Test Plan (dev server):
```
make db_stress
./db_stress
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5937

Differential Revision: D17997647

Pulled By: riversand963

fbshipit-source-id: 1a8d9994f89ce198935566756947c518f0052410

Summary:
Example: using the tool before and after PR https://github.com/facebook/rocksdb/issues/5784 shows that
the refactoring, presumed performance-neutral, actually sped up SST
filters by about 3% to 8% (repeatable result):

Before:
-  Dry run ns/op: 22.4725
-  Single filter ns/op: 51.1078
-  Random filter ns/op: 120.133

After:
+  Dry run ns/op: 22.2301
+  Single filter run ns/op: 47.4313
+  Random filter ns/op: 115.9

Only tests filters for the block-based table (full filters and
partitioned filters - same implementation; not block-based filters),
which seems to be the recommended format/implementation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5825

Differential Revision: D17804987

Pulled By: pdillinger

fbshipit-source-id: 0f18a9c254c57f7866030d03e7fa4ba503bac3c5

Summary:
Make DeleteFileTest inherit DBTestBase to avoid code duplication.

Test Plan (on devserver)
```
$make deletefile_test
$./deletefile_test
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5822

Differential Revision: D17456750

Pulled By: riversand963

fbshipit-source-id: 224e97967da7b98838a98981cd5095d3230a814f

Summary:
Make class ObsoleteFilesTest inherit from DBTestBase.

Test plan (on devserver):
```
$COMPILE_WITH_ASAN=1 make obsolete_files_test
$./obsolete_files_test
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5820

Differential Revision: D17452348

Pulled By: riversand963

fbshipit-source-id: b09f4581a18022ca2bfd79f2836c0bf7083f5f25

Summary:
Refactoring to consolidate implementation details of legacy
Bloom filters. This helps to organize and document some related,
obscure code.

Also added make/cpp var TEST_CACHE_LINE_SIZE so that it's easy to
compile and run unit tests for non-native cache line size. (Fixed a
related test failure in db_properties_test.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5784

Test Plan:
make check, including Recently added Bloom schema unit tests
(in ./plain_table_db_test && ./bloom_test), and including with
TEST_CACHE_LINE_SIZE=128U and TEST_CACHE_LINE_SIZE=256U. Tested the
schema tests with temporary fault injection into new implementations.

Some performance testing with modified unit tests suggest a small to moderate
improvement in speed.

Differential Revision: D17381384

Pulled By: pdillinger

fbshipit-source-id: ee42586da996798910fc45ac0b6289147f16d8df

Summary:
This will allow us to fix history by having the code changes for PR#5784 properly attributed to it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5810

Differential Revision: D17400231

Pulled By: pdillinger

fbshipit-source-id: 2da8b1cdf2533cfedb35b5526eadefb38c291f09

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/5780

Test Plan: existing plain table unit test

Differential Revision: D17368629

Pulled By: pdillinger

fbshipit-source-id: f25409cdc2f39ebe8d5cbb599cf820270e6b5d26

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/5332

Differential Revision: D17242232

fbshipit-source-id: c0d4646556a1335e51ac7382b986ca7f6ced7b64

Summary:
Hi! guys,

I got errors on the ARM machine.

before:

```console
$ make static_lib
...
g++: error: unrecognized argument in option '-march=armv8-a+crc+crypto'
g++: note: valid arguments to '-march=' are: armv2 armv2a armv3 armv3m armv4 armv4t armv5 armv5e armv5t armv5te armv6 armv6-m armv6j armv6k armv6kz armv6s-m armv6t2 armv6z armv6zk armv7 armv7-a armv7-m armv7-r armv7e-m armv7ve armv8-a armv8-a+crc armv8.1-a armv8.1-a+crc iwmmxt iwmmxt2 native
```

Thanks!
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5766

Differential Revision: D17191117

fbshipit-source-id: 7a61e3a2a4a06f37faeb8429bd7314da54ec5868

Summary:
AtomicFlushStressTest is a powerful test, but right now we only run it for atomic_flush=true + disable_wal=true. We further extend it to the case where atomic_flush=false + disable_wal = false. All the workload generation and validation can stay the same.
Atomic flush crash test is also changed to switch between the two test scenarios. It makes the name "atomic flush crash test" out of sync from what it really does. We leave it as it is to avoid troubles with continous test set-up.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5729

Test Plan: Run "CRASH_TEST_KILL_ODD=188 TEST_TMPDIR=/dev/shm/ USE_CLANG=1 make whitebox_crash_test_with_atomic_flush", observe the settings used and see it passed.

Differential Revision: D16969791

fbshipit-source-id: 56e37487000ae631e31b0100acd7bdc441c04163

Summary:
Right now VerifyChecksum() doesn't do read-ahead. In some use cases, users won't be able to achieve good performance. With this change, by default, RocksDB will do a default readahead, and users will be able to overwrite the readahead size by passing in a ReadOptions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5713

Test Plan: Add a new unit test.

Differential Revision: D16860874

fbshipit-source-id: 0cff0fe79ac855d3d068e6ccd770770854a68413

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/5674

Differential Revision: D16870338

fbshipit-source-id: c8dac644b1479fa734b491f3a8d50151772290f7

Summary:
TSAN was not able to correctly instrument atomic bts and btr instructions, so
when TSAN is enabled implement those with std::atomic::fetch_or and
std::atomic::fetch_and. Also disable tests that fail on TSAN with false
negatives (we know these are false negatives because this other verifiably
correct program fails with the same TSAN error <link>)

```
make clean
TEST_TMPDIR=/dev/shm/rocksdb OPT=-g COMPILE_WITH_TSAN=1 make J=1 -j56 folly_synchronization_distributed_mutex_test
```

This is the code that fails with the same false-negative with TSAN
```
namespace {
class ExceptionWithConstructionTrack : public std::exception {
 public:
  explicit ExceptionWithConstructionTrack(int id)
      : id_{folly::to<std::string>(id)}, constructionTrack_{id} {}

  const char* what() const noexcept override {
    return id_.c_str();
  }

 private:
  std::string id_;
  TestConstruction constructionTrack_;
};

template <typename Storage, typename Atomic>
void transferCurrentException(Storage& storage, Atomic& produced) {
  assert(std::current_exception());
  new (&storage) std::exception_ptr(std::current_exception());
  produced->store(true, std::memory_order_release);
}

void concurrentExceptionPropagationStress(
    int numThreads,
    std::chrono::milliseconds milliseconds) {
  auto&& stop = std::atomic<bool>{false};
  auto&& exceptions = std::vector<std::aligned_storage<48, 8>::type>{};
  auto&& produced = std::vector<std::unique_ptr<std::atomic<bool>>>{};
  auto&& consumed = std::vector<std::unique_ptr<std::atomic<bool>>>{};
  auto&& consumers = std::vector<std::thread>{};
  for (auto i = 0; i < numThreads; ++i) {
    produced.emplace_back(new std::atomic<bool>{false});
    consumed.emplace_back(new std::atomic<bool>{false});
    exceptions.push_back({});
  }

  auto producer = std::thread{[&]() {
    auto counter = std::vector<int>(numThreads, 0);
    for (auto i = 0; true; i = ((i + 1) % numThreads)) {
      try {
        throw ExceptionWithConstructionTrack{counter.at(i)++};
      } catch (...) {
        transferCurrentException(exceptions.at(i), produced.at(i));
      }

      while (!consumed.at(i)->load(std::memory_order_acquire)) {
        if (stop.load(std::memory_order_acquire)) {
          return;
        }
      }

      consumed.at(i)->store(false, std::memory_order_release);
    }
  }};

  for (auto i = 0; i < numThreads; ++i) {
    consumers.emplace_back([&, i]() {
      auto counter = 0;
      while (true) {
        while (!produced.at(i)->load(std::memory_order_acquire)) {
          if (stop.load(std::memory_order_acquire)) {
            return;
          }
        }
        produced.at(i)->store(false, std::memory_order_release);

        try {
          auto storage = &exceptions.at(i);
          auto exc = folly::launder(
            reinterpret_cast<std::exception_ptr*>(storage));
          auto copy = std::move(*exc);
          exc->std::exception_ptr::~exception_ptr();
          std::rethrow_exception(std::move(copy));
        } catch (std::exception& exc) {
          auto value = std::stoi(exc.what());
          EXPECT_EQ(value, counter++);
        }

        consumed.at(i)->store(true, std::memory_order_release);
      }
    });
  }

  std::this_thread::sleep_for(milliseconds);
  stop.store(true);
  producer.join();
  for (auto& thread : consumers) {
    thread.join();
  }
}
} // namespace
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5684

Differential Revision: D16746077

Pulled By: miasantreble

fbshipit-source-id: 8af88dcf9161c05daec1a76290f577918638f79d

Summary:
This ports `folly::DistributedMutex` into RocksDB. The PR includes everything else needed to compile and use DistributedMutex as a component within folly. Most files are unchanged except for some portability stuff and includes.

For now, I've put this under `rocksdb/third-party`, but if there is a better folder to put this under, let me know. I also am not sure how or where to put unit tests for third-party stuff like this. It seems like gtest is included already, but I need to link with it from another third-party folder.

This also includes some other common components from folly

- folly/Optional
- folly/ScopeGuard (In particular `SCOPE_EXIT`)
- folly/synchronization/ParkingLot (A portable futex-like interface)
- folly/synchronization/AtomicNotification (The standard C++ interface for futexes)
- folly/Indestructible (For singletons that don't get destroyed without allocations)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5642

Differential Revision: D16544439

fbshipit-source-id: 179b98b5dcddc3075926d31a30f92fd064245731

Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
      const ReadOptions& options, ColumnFamilyHandle* column_family,
      const Slice& key, PinnableSlice* merge_operands,
      GetMergeOperandsOptions* get_merge_operands_options,
      int* number_of_operands)

Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);

Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604

Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist

Differential Revision: D16657366

Pulled By: vjnadimpalli

fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf