Summary:
this PR fixes a few failed contbuild:
1. ASAN memory leak in Block::NewIterator (table/block.cc:429). the proper destruction of first_level_iter_ and second_level_iter_ of two_level_iterator.cc is missing from the code after the refactoring in https://github.com/facebook/rocksdb/pull/3406
2. various unused param errors introduced by https://github.com/facebook/rocksdb/pull/3662
3. updated comment for `ForceReleaseCachedEntry` to emphasize the use of `force_erase` flag.
Closes https://github.com/facebook/rocksdb/pull/3718

Reviewed By: maysamyabandeh

Differential Revision: D7621192

Pulled By: miasantreble

fbshipit-source-id: 476c94264083a0730ded957c29de7807e4f5b146

Reviewed By: igorsugak

fbshipit-source-id: 4a93675cc1931089ddd574cacdb15d228b1e5f37

Reviewed By: everiq, igorsugak

Differential Revision: D7046710

fbshipit-source-id: 8e10b1f1e2aecebbfb229c742e214db887e5a461

Summary:
After af92d4ad, only exclusive manual compaction can have conflict. dc360df8 updated the conflict-checking test case accordingly. But we missed the point that exclusive manual compaction can only conflict with automatic compactions scheduled after it, since it waits on pending automatic compactions before it begins running.

This PR updates the test case to ensure the automatic compactions are scheduled after the manual compaction starts but before it finishes, thus ensuring a conflict. I also cleaned up the test case to use less space as I saw it cause out-of-space error on travis.
Closes https://github.com/facebook/rocksdb/pull/3375

Differential Revision: D6735162

Pulled By: ajkr

fbshipit-source-id: 020530a4e150a4786792dce7cec5d66b420cb884

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

Summary:
This reverts the previous commit 1d7048c5, which broke the build.

Did a `git revert 1d7048c5`.
Closes https://github.com/facebook/rocksdb/pull/2627

Differential Revision: D5476473

Pulled By: sagar0

fbshipit-source-id: 4756ff5c0dfc88c17eceb00e02c36176de728d06

Summary: This uses `clang-tidy` to comment out unused parameters (in functions, methods and lambdas) in fbcode. Cases that the tool failed to handle are fixed manually.

Reviewed By: igorsugak

Differential Revision: D5454343

fbshipit-source-id: 5dee339b4334e25e963891b519a5aa81fbf627b2

Summary:
Fix column_family_test with LITE build. I need this patch to fix 5.6 branch.
Closes https://github.com/facebook/rocksdb/pull/2597

Differential Revision: D5437171

Pulled By: yiwu-arbug

fbshipit-source-id: 88b9dc5925a6b47af10c1b41bc5b07c4251a84b5

Summary: Closes https://github.com/facebook/rocksdb/pull/2589

Differential Revision: D5431502

Pulled By: siying

fbshipit-source-id: 8ebf8c87883daa9daa54b2303d11ce01ab1f6f75

Summary:
Throughput: 46k tps in our sysbench settings (filling the details later)

The idea is to have the simplest change that gives us a reasonable boost
in 2PC throughput.

Major design changes:
1. The WAL file internal buffer is not flushed after each write. Instead
it is flushed before critical operations (WAL copy via fs) or when
FlushWAL is called by MySQL. Flushing the WAL buffer is also protected
via mutex_.
2. Use two sequence numbers: last seq, and last seq for write. Last seq
is the last visible sequence number for reads. Last seq for write is the
next sequence number that should be used to write to WAL/memtable. This
allows to have a memtable write be in parallel to WAL writes.
3. BatchGroup is not used for writes. This means that we can have
parallel writers which changes a major assumption in the code base. To
accommodate for that i) allow only 1 WriteImpl that intends to write to
memtable via mem_mutex_--which is fine since in 2PC almost all of the memtable writes
come via group commit phase which is serial anyway, ii) make all the
parts in the code base that assumed to be the only writer (via
EnterUnbatched) to also acquire mem_mutex_, iii) stat updates are
protected via a stat_mutex_.

Note: the first commit has the approach figured out but is not clean.
Submitting the PR anyway to get the early feedback on the approach. If
we are ok with the approach I will go ahead with this updates:
0) Rebase with Yi's pipelining changes
1) Currently batching is disabled by default to make sure that it will be
consistent with all unit tests. Will make this optional via a config.
2) A couple of unit tests are disabled. They need to be updated with the
serial commit of 2PC taken into account.
3) Replacing BatchGroup with mem_mutex_ got a bit ugly as it requires
releasing mutex_ beforehand (the same way EnterUnbatched does). This
needs to be cleaned up.
Closes https://github.com/facebook/rocksdb/pull/2345

Differential Revision: D5210732

Pulled By: maysamyabandeh

fbshipit-source-id: 78653bd95a35cd1e831e555e0e57bdfd695355a4

Summary:
CreateColumnFamily() releases DB mutex after adding column family to the set and install super version (to write option file), so if users call GetAggregatedIntProperty() in the middle, then super version will be null and the process will crash. Fix it by skipping those column families without super version installed.

Maybe we should also fix the problem of releasing the lock when reading option file, but it is more risky. so I'm doing a quick and safer fix and we can investigate it later.
Closes https://github.com/facebook/rocksdb/pull/2475

Differential Revision: D5298053

Pulled By: siying

fbshipit-source-id: 4b3c8f91c60400b163fcc6cda8a0c77723be0ef6

Summary:
stop calling Close() at the end of tests holding a compaction pressure token since it causes the write controller to be deleted while it's still needed. these calls were pointless anyways since Close() is already called in the test's destructor.
Closes https://github.com/facebook/rocksdb/pull/2367

Differential Revision: D5125906

Pulled By: ajkr

fbshipit-source-id: 6cad8673e5546a82ff602ac0ba59cc3f68dbde46

Summary:
- `max_background_flushes` and `max_background_compactions` are still supported for backwards compatibility
- `base_background_compactions` is completely deprecated. Now we just throttle to one background compaction when there's no pressure.
- `max_background_jobs` is added to automatically partition the concurrent background jobs into flushes vs compactions. Currently it's very simple as we just allocate one-fourth of the jobs to flushes, and the remaining can be used for compactions.
- The test cases that set `base_background_compactions > 1` needed to be updated. I just grab the pressure token such that the desired number of compactions can be scheduled.
Closes https://github.com/facebook/rocksdb/pull/2205

Differential Revision: D4937461

Pulled By: ajkr

fbshipit-source-id: df52cbbd497e13bbc9a60560a5ac2a2526b3f1f9

Summary:
TSAN shows warning of data race of EnvCounter::num_new_writable_file_. Make it atomic.
Closes https://github.com/facebook/rocksdb/pull/2331

Differential Revision: D5089215

Pulled By: siying

fbshipit-source-id: 15f6dcfb770a3310cbb6337c22482c8b330daffc

Summary:
Fix ColumnFamilyTest:BulkAddDrop not deleted CF handles at the end, causing ASAN failure.
Closes https://github.com/facebook/rocksdb/pull/2275

Differential Revision: D5040724

Pulled By: yiwu-arbug

fbshipit-source-id: 86cd4070c944d01173a3cc36462bb800698af192

Summary:
Adding DB::CreateColumnFamilie() and DB::DropColumnFamilies() to bulk create/drop column families. This is to address the problem creating/dropping 1k column families takes minutes. The bottleneck is we persist options files for every single column family create/drop, and it parses the persisted options file for verification, which take a lot CPU time.

The new APIs simply create/drop column families individually, and persist options file once at the end. This improves create 1k column families to within ~0.1s. Further improvement can be merge manifest write to one IO.
Closes https://github.com/facebook/rocksdb/pull/2248

Differential Revision: D5001578

Pulled By: yiwu-arbug

fbshipit-source-id: d4e00bda671451e0b314c13e12ad194b1704aa03

Summary:
Move some files under util/ to new directories env/, monitoring/ options/ and cache/
Closes https://github.com/facebook/rocksdb/pull/2090

Differential Revision: D4833681

Pulled By: siying

fbshipit-source-id: 2fd8bef

Summary:
Level-based L0->L0 compaction operates on spans of files that aren't currently being compacted. It reduces the number of L0 files, thus making write stall conditions harder to reach.

- L0->L0 is triggered when base level is unavailable due to pending compactions
- L0->L0 always outputs one file of at most `max_level0_burst_file_size` bytes.
- Subcompactions are disabled for L0->L0 since we want to output one file.
- Input files are chosen as the longest span of available files that will fit within the size limit. This minimizes number of files in L0.
Closes https://github.com/facebook/rocksdb/pull/2027

Differential Revision: D4760318

Pulled By: ajkr

fbshipit-source-id: 9d07183

Summary:
Add two DB properties: rocksdb.actual_delayed_write_rate and rocksdb.is_write_stooped, for people to know whether current writes are being throttled.
Closes https://github.com/facebook/rocksdb/pull/2043

Differential Revision: D4782975

Pulled By: siying

fbshipit-source-id: 6b2f5cf

Summary:
Remove disableDataSync, and another similarly named disable_data_sync options.
This is being done to simplify options, and also because the performance gains of this feature can be achieved by other methods.
Closes https://github.com/facebook/rocksdb/pull/1859

Differential Revision: D4541292

Pulled By: sagar0

fbshipit-source-id: 5b3a6ca

Summary:
introduce new methods into a public threadpool interface,
- allow submission of std::functions as they allow greater flexibility.
- add Joining methods to the implementation to join scheduled and submitted jobs with
  an option to cancel jobs that did not start executing.
- Remove ugly `#ifdefs` between pthread and std implementation, make it uniform.
- introduce pimpl for a drop in replacement of the implementation
- Introduce rocksdb::port::Thread typedef which is a replacement for std::thread.  On Posix Thread defaults as before std::thread.
- Implement WindowsThread that allocates memory in a more controllable manner than windows std::thread with a replaceable implementation.
- should be no functionality changes.
Closes https://github.com/facebook/rocksdb/pull/1823

Differential Revision: D4492902

Pulled By: siying

fbshipit-source-id: c74cb11

Summary:
Current write stalling system has the problem of lacking of positive feedback if the restricted rate is already too low. Users sometimes stack in very low slowdown value. With the diff, we add a positive feedback (increasing the slowdown value) if we recover from slowdown state back to normal. To avoid the positive feedback to keep the slowdown value to be to high, we add issue a negative feedback every time we are close to the stop condition. Experiments show it is easier to reach a relative balance than before.

Also increase level0_stop_writes_trigger default from 24 to 32. Since level0_slowdown_writes_trigger default is 20, stop trigger 24 only gives four files as the buffer time to slowdown writes. In order to avoid stop in four files while 20 files have been accumulated, the slowdown value must be very low, which is amost the same as stop. It also doesn't give enough time for the slowdown value to converge. Increase it to 32 will smooth out the system.
Closes https://github.com/facebook/rocksdb/pull/1562

Differential Revision: D4218519

Pulled By: siying

fbshipit-source-id: 95e4088

Summary: Closes https://github.com/facebook/rocksdb/pull/1496

Differential Revision: D4168080

Pulled By: siying

fbshipit-source-id: 056ae62

Summary: Closes https://github.com/facebook/rocksdb/pull/1490

Differential Revision: D4158821

Pulled By: IslamAbdelRahman

fbshipit-source-id: 59b73f4

Summary:
change ioptions.comparator to user_comparator instread of internal_comparator.
Also change Comparator* to InternalKeyComparator* to make its type explicitly.

Test Plan: make all check -j64

Reviewers: andrewkr, sdong, yiwu

Reviewed By: yiwu

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D65121

Summary: Some tests in column_family_test depend on functions that are not available in LITE build, which sometimes cause flakiness. Disable them.

Test Plan: Run those tests in LITE build.

Reviewers: yiwu, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D65271

Summary:
Add DB::SetDBOptions to dynamic change max_background_compactions and base_background_compactions.
I'll add more dynamic changeable options soon.

Test Plan: unit test.

Reviewers: yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D64749

Summary: Use ImmutableDBOptions/MutableDBOptions internally and DBOptions only for user-facing APIs. MutableDBOptions is barely a placeholder for now. I'll start to move options to MutableDBOptions in following diffs.

Test Plan:
  make all check

Reviewers: yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D64065

Summary:
* Change constructor of MutableCFOptions to depends only on ColumnFamilyOptions.
* Move `max_subcompactions`, `compaction_options_fifo` and `compaction_pri` to ImmutableCFOptions to make it clear that they are immutable.

Test Plan: existing unit tests.

Reviewers: yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D63945

Summary: In ColumnFamilyTest.FlushCloseWALFiles, there is a small window in which the flush has finished but the log writer is not yet closed, causing the assert failure. Fix it by explicitly waiting the flush job to finish.

Test Plan: Run the test many times in high parallelism.

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D63423

Merge options source_compaction_factor, max_grandparent_overlap_bytes and expanded_compaction_factor into max_compaction_bytes

Summary: To reduce number of options, merge source_compaction_factor, max_grandparent_overlap_bytes and expanded_compaction_factor into max_compaction_bytes.

Test Plan: Add two new unit tests. Run all existing tests, including jtest.

Reviewers: yhchiang, igor, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D59829

read_options.background_purge_on_iterator_cleanup to cover forward iterator and log file closing too.

Summary: With read_options.background_purge_on_iterator_cleanup=true, File deletion and closing can still happen in forward iterator, or WAL file closing. Cover those cases too.

Test Plan: I am adding unit tests.

Reviewers: andrewkr, IslamAbdelRahman, yiwu

Reviewed By: yiwu

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D61503

Summary:
My understanding is that the purpose of write stall triggers are to wait for auto-compaction to catch up. Without auto-compaction, we don't need to stall writes.

Also with this diff, flush/compaction conditions are recalculated on dynamic option change. Previously the conditions are recalculate only when write stall options are changed.

Test Plan: See the new test. Removed two tests that are no longer valid.

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D61437

Add a GetComparator() function to the ColumnFamilyHandle base class so that the user's comparator can be retrieved.

Summary: MyRocks is adding support for the user of the SstFileWriter which needs a comparator.  It would be more convenient to get the comparator from the column family (which already has to have it) than to have caller keep track of it.

Test Plan: Standard tests (adding one for the new method)

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D61155

Summary:
Stale log files can be deleted out of order. This can happen for various reasons. One of the reason is that no data is ever inserted to a column family and we have an optimization to update its log number, but not all the old log files are cleaned up (the case shown in the unit tests added). It can also happen when we simply delete multiple log files out of order.

This causes data corruption because we simply increase seqID after processing the next row and we may end up with writing data with smaller seqID than what is already flushed to memtables.

In DB recovery, for the oldest files we are replaying, if there it contains no data for any column family, we ignore the sequence IDs in the file.

Test Plan: Add two unit tests that fail without the fix.

Reviewers: IslamAbdelRahman, igor, yiwu

Reviewed By: yiwu

Subscribers: hermanlee4, yoshinorim, leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D60891

Summary: Multiput atomiciy is broken across multiple column families if we don't sync WAL before flushing one column family. The WAL file may contain a write batch containing writes to a key to the CF to be flushed and a key to other CF. If we don't sync WAL before flushing, if machine crashes after flushing, the write batch will only be partial recovered. Data to other CFs are lost.

Test Plan: Add a new unit test which will fail without the diff.

Reviewers: yhchiang, IslamAbdelRahman, igor, yiwu

Reviewed By: yiwu

Subscribers: yiwu, leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D60915

Summary:
add DestroyColumnFamilyHandle(ColumnFamilyHandle**) to close column family instead of deleting cfh*
User should call this to close a cf and then we can detect the deletion in this function.

Test Plan: make all check -j64

Reviewers: andrewkr, yiwu, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D60765

Summary: We saw instances where total_log_size is off the real value, but I'm not able to reproduce it. Add more logging to help debugging when it happens again.

Test Plan: Run the unit test and see the logging.

Reviewers: andrewkr, yhchiang, igor, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D60081

Summary:
Add a test to detect that when WAL gets truncated,
seq no's are checked to be contiguous.

This test is put in ColumnFamilyTest as it has the necessary
infrastructure/functions for flushing column families, which
we use to ensure 2 active WAL files

Test Plan:
This is a test, no feature has been added.
This test fails today and hence disabled

Reviewers: sdong

Reviewed By: sdong

Subscribers: lgalanis, dhruba, andrewkr, pritamdamania

Differential Revision: https://reviews.facebook.net/D59253

Summary: Reduce use of argument-dependent name lookup in RocksDB.

Test Plan: 'make check' passed.

Reviewers: andrewkr

Reviewed By: andrewkr

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58203