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A library that provides an embeddable, persistent key-value store for fast storage.
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c0208dffbe
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Nikhil Benesch c0208dffbe arena: derive alignment unit from std::max_align_t 
Summary:
As raised in #2265, the arena allocator will return memory that is improperly aligned to store a `std::function` on macOS. Oddly, I'm unable to tickle this bug without adding a `std::function` field to `struct ReadOptions`—but my proposal in #2265 does exactly that.

In any case, here's a simple reproduction. Apply this bogus patch to get a `std::function` into `struct ReadOptions`

```
 --- a/include/rocksdb/options.h
+++ b/include/rocksdb/options.h
@@ -1035,6 +1035,8 @@ struct ReadOptions {
   // Default: 0
   uint64_t max_skippable_internal_keys;

+  std::function<void()> foo;
+
   ReadOptions();
   ReadOptions(bool cksum, bool cache);
 };
```

then compile `db_properties_test` *with ubsan* and run `ReadLatencyHistogramByLevel`:

```
$ make COMPILE_WITH_UBSAN=1 db_properties_test
$ ./db_properties_test --gtest_filter=DBPropertiesTest.ReadLatencyHistogramByLevel
```

ubsan will complain about several misaligned accesses:

```
Note: Google Test filter = DBPropertiesTest.ReadLatencyHistogramByLevel
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from DBPropertiesTest
[ RUN      ] DBPropertiesTest.ReadLatencyHistogramByLevel
util/coding.h:372:12: runtime error: load of misaligned address 0x00010d85516c for type 'const unsigned long', which requires 8 byte alignment
0x00010d85516c: note: pointer points here
  01 00 34 57 00 00 00 00  02 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  78 24 82 0a 01 00 00 00
              ^
util/coding.h:362:3: runtime error: store to misaligned address 0x7fff5733fac4 for type 'unsigned long', which requires 8 byte alignment
0x7fff5733fac4: note: pointer points here
  01 00 00 00 00 00 00 00  02 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  80 1d 96 0d 01 00 00 00
              ^
util/coding.h:372:12: runtime error: load of misaligned address 0x00010d85516c for type 'const unsigned long', which requires 8 byte alignment
0x00010d85516c: note: pointer points here
  01 00 34 57 00 00 00 00  02 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  78 24 82 0a 01 00 00 00
              ^
version_set.cc:854: runtime error: constructor call on misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
version_set.cc:512: runtime error: constructor call on misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
version_set.cc:505: runtime error: constructor call on misaligned address 0x00010dbfa5e8 for type 'rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
options.h:931: runtime error: constructor call on misaligned address 0x00010dbfa5e8 for type 'rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
options.h:931: runtime error: constructor call on misaligned address 0x00010dbfa628 for type 'std::__1::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
functional:1583: runtime error: constructor call on misaligned address 0x00010dbfa628 for type 'std::__1::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/functional:1585:9: runtime error: member access within misaligned address 0x00010dbfa628 for type 'std::__1::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/functional:1585:9: runtime error: store to misaligned address 0x00010dbfa648 for type '__base *' (aka '__base<void ()> *'), which requires 16 byte alignment
0x00010dbfa648: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
db/version_set.cc:864:29: runtime error: upcast of misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:521:12: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:521:12: runtime error: load of misaligned address 0x00010dbfa5d8 for type 'rocksdb::TableCache *', which requires 16 byte alignment
0x00010dbfa5d8: note: pointer points here
 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00
              ^
db/version_set.cc:522:9: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:522:9: runtime error: reference binding to misaligned address 0x00010dbfa5e8 for type 'const rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
db/version_set.cc:522:24: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:522:38: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:522:57: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:522:57: runtime error: load of misaligned address 0x00010dbfa678 for type 'rocksdb::RangeDelAggregator *', which requires 16 byte alignment
0x00010dbfa678: note: pointer points here
 01 00 00 00  d0 a1 bf 0d 01 00 00 00  00 00 00 00 00 00 00 00  f8 db 70 0a 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:523:54: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:523:54: runtime error: load of misaligned address 0x00010dbfa668 for type 'rocksdb::HistogramImpl *', which requires 16 byte alignment
0x00010dbfa668: note: pointer points here
 01 00 00 00  c8 88 a5 0d 01 00 00 00  00 00 00 00 01 00 00 00  d0 a1 bf 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:524:9: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:524:47: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:524:62: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/table_cache.cc:228:33: runtime error: reference binding to misaligned address 0x00010dbfa5e8 for type 'const rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
table/block_based_table_reader.cc:1554:41: runtime error: reference binding to misaligned address 0x00010dbfa5e8 for type 'const rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
table/block_based_table_reader.cc:1396:21: runtime error: reference binding to misaligned address 0x00010dbfa5e8 for type 'const rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
include/rocksdb/options.h:931:8: runtime error: reference binding to misaligned address 0x00010dbfa628 for type 'const std::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/functional:1584:13: runtime error: load of misaligned address 0x00010dbfa648 for type '__base *const' (aka '__base<void ()> *const'), which requires 16 byte alignment
0x00010dbfa648: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  c8 a5 97 0d 01 00 00 00  38 36 9b 0d
              ^
table/block_based_table_reader.cc:1555:24: runtime error: reference binding to misaligned address 0x00010dbfa5e8 for type 'const rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
db/table_cache.cc:244:54: runtime error: load of misaligned address 0x00010dbfa618 for type 'const bool', which requires 16 byte alignment
0x00010dbfa618: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
db/table_cache.cc:246:49: runtime error: reference binding to misaligned address 0x00010dbfa5e8 for type 'const rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
db/version_set.cc:532:12: runtime error: member access within misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
db/version_set.cc:532:12: runtime error: member access within misaligned address 0x00010dbfa5e8 for type 'const rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
db/version_set.cc:532:26: runtime error: load of misaligned address 0x00010dbfa5f8 for type 'const rocksdb::Slice *const', which requires 16 byte alignment
0x00010dbfa5f8: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
version_set.cc:493: runtime error: member call on misaligned address 0x00010dbfa5c8 for type 'rocksdb::(anonymous namespace)::LevelFileIteratorState', which requires 16 byte alignment
0x00010dbfa5c8: note: pointer points here
 00 00 00 00  a0 db 70 0a 01 00 00 00  00 00 00 00 00 00 00 00  90 14 98 0d 01 00 00 00  00 00 00 00
              ^
version_set.cc:493: runtime error: member call on misaligned address 0x00010dbfa5e8 for type 'rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
options.h:931: runtime error: member call on misaligned address 0x00010dbfa5e8 for type 'rocksdb::ReadOptions', which requires 16 byte alignment
0x00010dbfa5e8: note: pointer points here
 00 00 00 00  01 01 ff ff ff ff ff ff  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
options.h:931: runtime error: member call on misaligned address 0x00010dbfa628 for type 'std::__1::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
functional:1765: runtime error: member call on misaligned address 0x00010dbfa628 for type 'std::__1::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/functional:1766:9: runtime error: member access within misaligned address 0x00010dbfa628 for type 'std::__1::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/functional:1766:9: runtime error: load of misaligned address 0x00010dbfa648 for type '__base *' (aka '__base<void ()> *'), which requires 16 byte alignment
0x00010dbfa648: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  c8 a5 97 0d 01 00 00 00  38 36 9b 0d
              ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/functional:1766:27: runtime error: member access within misaligned address 0x00010dbfa628 for type 'std::__1::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/functional:1768:14: runtime error: member access within misaligned address 0x00010dbfa628 for type 'std::__1::function<void ()>', which requires 16 byte alignment
0x00010dbfa628: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/functional:1768:14: runtime error: load of misaligned address 0x00010dbfa648 for type '__base *' (aka '__base<void ()> *'), which requires 16 byte alignment
0x00010dbfa648: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  c8 a5 97 0d 01 00 00 00  38 36 9b 0d
              ^
[       OK ] DBPropertiesTest.ReadLatencyHistogramByLevel (1599 ms)
[----------] 1 test from DBPropertiesTest (1599 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (1599 ms total)
[  PASSED  ] 1 test.
```

So it seems the root cause is that the internal implementation of `std::function` on macOS (and perhaps with libc++ generally?) requires 16-byte aligned memory, but the arena allocator only guarantees that the returned memory will be `sizeof(void*)` aligned, which is only 8-byte alignment on my machine. This patch solves the problem by adjusting the allocator to derive the necessary alignment from `alignof(std::max_align_t)`, which is properly 16 bytes on my machine.

As I mentioned in #2265, none of RocksDB's tests will cause this unaligned access to actually abort the process, but, on macOS, linking CockroachDB against a version of RocksDB with the above patch and letting it run for just a few seconds will cause a SIGABRT.

```
Process 19792 stopped
* thread #2, stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
    frame #0: 0x0000000004f5e78f cockroach`DBNewIter + 95
cockroach`DBNewIter:
->  0x4f5e78f <+95>:  callq  *0x28(%rax)
    0x4f5e792 <+98>:  jmp    0x4f5e79e                 ; <+110>
    0x4f5e794 <+100>: movq   -0x50(%rbp), %rcx
    0x4f5e798 <+104>: movq   %rax, %rdi
(lldb) bt
* thread #2, stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
  * frame #0: 0x0000000004f5e78f cockroach`DBNewIter + 95
```

I'd get you a backtrace, but [Go doesn't include cgo debug information on macOS](https://github.com/golang/go/issues/6942). I've also tried building against libc++ on Linux, where debug information would be available, but I can't seem to trigger the bug there.

In any case, this PR both fixes the segfault in CockroachDB and fixes the warnings reported by ubsan.
Closes https://github.com/facebook/rocksdb/pull/2347

Differential Revision: D5108596

Pulled By: yiwu-arbug

fbshipit-source-id: bd5e4323b2ce915ed4fe78e123cb8996aec75a00
2017-10-17 11:13:19 -07:00
buckifier rocksdb: make buildable on aarch64 2017-08-13 17:13:54 -07:00
build_tools fix lite build 2017-10-17 08:57:09 -07:00
cache Add -DPORTABLE=1 to MSVC CI build 2017-08-31 16:42:48 -07:00
cmake CMake: Add support for CMake packages 2017-08-28 17:14:37 -07:00
coverage Fix /bin/bash shebangs 2017-08-03 15:56:46 -07:00
db arena: derive alignment unit from std::max_align_t 2017-10-17 11:13:19 -07:00
docs Blog post for 5.8 release 2017-09-28 10:14:09 -07:00
env Repair DBs with trailing slash in name 2017-09-22 12:42:22 -07:00
examples Pinnableslice examples and blog post 2017-08-24 12:26:07 -07:00
hdfs Revert "comment out unused parameters" 2017-07-21 18:26:26 -07:00
include/rocksdb Move ~Comparator define to comparator.h 2017-10-17 09:58:13 -07:00
java Add OptionsUtil class to java/CMakeLists.txt 2017-10-12 16:57:05 -07:00
memtable Added CPU prefetch for skiplist 2017-10-04 18:12:52 -07:00
monitoring Use RAII instead of pointers in cf_info_map 2017-09-28 14:26:47 -07:00
options fix lite build 2017-10-17 08:57:09 -07:00
port Fix MinGW build 2017-09-19 10:28:26 -07:00
table print more table_options to info log 2017-10-13 14:42:26 -07:00
third-party Revert "comment out unused parameters" 2017-07-21 18:26:26 -07:00
tools db_bench randomtransaction print throughput 2017-10-16 18:42:25 -07:00
util arena: derive alignment unit from std::max_align_t 2017-10-17 11:13:19 -07:00
utilities Blob DB: Move BlobFile definition to a separate file 2017-10-13 14:42:26 -07:00
.clang-format A script that automatically reformat affected lines 2014-01-14 12:21:24 -08:00
.gitignore Remove leftover references to phutil_module_cache 2017-08-23 12:12:21 -07:00
.travis.yml fix lite build 2017-10-17 08:57:09 -07:00
appveyor.yml Add -DPORTABLE=1 to MSVC CI build 2017-08-31 16:42:48 -07:00
AUTHORS Add AUTHORS file. Fix #203 2014-09-29 10:52:18 -07:00
CMakeLists.txt PinnableSlice move assignment 2017-10-12 18:28:24 -07:00
CONTRIBUTING.md Remove the licensing description in CONTRIBUTING.md 2017-07-16 15:57:18 -07:00
COPYING Add GPLv2 as an alternative license. 2017-04-27 18:06:12 -07:00
DEFAULT_OPTIONS_HISTORY.md options.delayed_write_rate use the rate of rate_limiter by default. 2017-05-24 09:58:24 -07:00
DUMP_FORMAT.md First version of rocksdb_dump and rocksdb_undump. 2015-06-19 16:24:36 -07:00
HISTORY.md rate limit auto-tuning 2017-10-04 19:15:01 -07:00
INSTALL.md Default one to rocksdb:x64-windows 2017-09-28 16:12:24 -07:00
issue_template.md Add a template for issues 2017-09-29 11:41:28 -07:00
LANGUAGE-BINDINGS.md add Erlang to the list of language bindings 2017-08-28 16:43:16 -07:00
LICENSE.Apache Change RocksDB License 2017-07-15 16:11:23 -07:00
LICENSE.leveldb Add back the LevelDB license file 2017-07-16 18:42:18 -07:00
Makefile PinnableSlice move assignment 2017-10-12 18:28:24 -07:00
README.md Appveyor badge to show master branch 2016-07-26 13:54:08 -07:00
ROCKSDB_LITE.md Optimistic Transactions 2015-05-29 14:36:35 -07:00
src.mk PinnableSlice move assignment 2017-10-12 18:28:24 -07:00
TARGETS PinnableSlice move assignment 2017-10-12 18:28:24 -07:00
thirdparty.inc Introduce XPRESS compresssion on Windows. (#1081) 2016-04-19 22:54:24 -07:00
USERS.md Add LogDevice to USERS.md 2017-09-25 15:56:40 -07:00
Vagrantfile Update Vagrant file (test internal phabricator workflow) 2016-10-28 15:39:19 -07:00
WINDOWS_PORT.md Commit both PR and internal code review changes 2015-07-07 16:58:20 -07:00

README.md

RocksDB: A Persistent Key-Value Store for Flash and RAM Storage

Build Status Build status

RocksDB is developed and maintained by Facebook Database Engineering Team. It is built on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)

This code is a library that forms the core building block for a fast key value server, especially suited for storing data on flash drives. It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF) and Space-Amplification-Factor (SAF). It has multi-threaded compactions, making it specially suitable for storing multiple terabytes of data in a single database.

Start with example usage here: https://github.com/facebook/rocksdb/tree/master/examples

See the github wiki for more explanation.

The public interface is in include/. Callers should not include or rely on the details of any other header files in this package. Those internal APIs may be changed without warning.

Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/