Summary:
**Summary:**
Simplified the code layout by moving FIFOCompactionPicker to a separate file.
**Why?:**
While trying to add ttl functionality to universal compaction, I found that `FIFOCompactionPicker` class and its impl methods to be interspersed between `LevelCompactionPicker` methods which kind-of made the code a little hard to traverse. So I moved `FIFOCompactionPicker` to a separate compaction_picker_fifo.h/cc file, similar to `UniversalCompactionPicker`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4724

Differential Revision: D13227914

Pulled By: sagar0

fbshipit-source-id: 89471766ea67fa4d87664a41c057dd7df4b3d4e3

Summary:
There is a race condition in DBFlushTest.SyncFail, as illustrated below.
```
time         thread1                             bg_flush_thread
  |     Flush(wait=false, cfd)
  |     refs_before=cfd->current()->TEST_refs()   PickMemtable calls cfd->current()->Ref()
  V
```
The race condition between thread1 getting the ref count of cfd's current
version and bg_flush_thread incrementing the cfd's current version makes it
possible for later assertion on refs_before to fail. Therefore, we add test
sync points to enforce the order and assert on the ref count before and after
PickMemtable is called in bg_flush_thread.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4633

Differential Revision: D12967131

Pulled By: riversand963

fbshipit-source-id: a99d2bacb7869ec5d8d03b24ef2babc0e6ae1a3b

Summary:
there is chance that

* the caller tries to repair the db when holding the db_lock, in
  that case the env implementation might not set the `lock`
  parameter of Repairer::Run().
* the caller somehow never calls Repairer::Run().

either way, the desctructor of Repair will compare the uninitialized
db_lock_ with nullptr, and tries to unlock it. there is good chance
that the db_lock_ is not nullptr, then boom.
Signed-off-by: NKefu Chai <tchaikov@gmail.com>
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4683

Differential Revision: D13260287

Pulled By: riversand963

fbshipit-source-id: 878a119d2e9f10a0fa17ee62cf3fb24b33d49fa5

Summary:
Add a dummy main() in sst_file_reader_test for ROCKSDB_LITE to fix link failure in regression
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4725

Differential Revision: D13252885

Pulled By: anand1976

fbshipit-source-id: 0e22b964815e2bf01aff7d03ed4ae59d44fa86f1

Summary:
Currently the garbage collection of items in old_commit_map_ was done upon ::ReleaseSnapshot. The assumption behind this method was that the sequence number of snapshots are unique, which is incorrect. In the very rare cases that two consecutive snapshot have the same sequence number this could lead the release of the first snapshot affect the old_commit_map_ that is necessary to service the reads of the second snapshot. The bug would be triggered only if i) two snapshot have the same seq, ii) both of them are very old (older than the last ~4m transactions), and iii) there is commit entry overlapping with the snapshot seq number.
It is fixed by doing the cleanup of old_commit_map_ in UpdateSnapshot: the new list of snapshots are compared with the old one and the missing sequence numbers are concluded released. If two snapshots have the same seq number, after the release of one of them, the seq number still appears in the snapshot least and thus not cleaned up prematurely.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4727

Differential Revision: D13246495

Pulled By: maysamyabandeh

fbshipit-source-id: 93b87a5042afd8060889df245526d3f5d29de9fe

Summary:
Fix block based table reader not using memory_allocator when allocating index blocks and compression dictionary blocks.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4678

Differential Revision: D13054594

Pulled By: yiwu-arbug

fbshipit-source-id: 379f25bcc665395662511c4f873f4b7b55104ce2

Summary:
Removed `one_time_use` flag, which removed the need for some
tests, and changed all `NewRangeTombstoneIterator` methods to return
`FragmentedRangeTombstoneIterators`.

These changes also led to removing `RangeDelAggregatorV2::AddUnfragmentedTombstones`
and one of the `MemTableListVersion::AddRangeTombstoneIterators` methods.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4692

Differential Revision: D13106570

Pulled By: abhimadan

fbshipit-source-id: cbab5432d7fc2d9cdfd8d9d40361a1bffaa8f845

Summary:
If user do not end the trace manually, the tracing will continue which can potential use up all the storage space and cause problem. In this PR, the max trace file size is added to the TraceOptions and user can set the value if they need or the default is 64GB.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4610

Differential Revision: D12893400

Pulled By: zhichao-cao

fbshipit-source-id: acf4b5a6076bb691778bdfbac4864e1006758953

Summary:
Mac build is failing with the below error:
```
$ make db_bench -j8
...
...
tools/db_bench_tool.cc:4583:25: error: no matching function for call to 'max'
              (uint64_t)std::max(0l, seek_pos - FLAGS_max_scan_distance),
                        ^~~~~~~~
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:2717:1: note: candidate template ignored: deduced conflicting types for parameter '_Tp' ('long' vs. 'long long')
max(const _Tp& __a, const _Tp& __b)
^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:2727:1: note: candidate template ignored: could not match 'initializer_list<type-parameter-0-0>' against 'long'
max(initializer_list<_Tp> __t, _Compare __comp)
^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:2709:1: note: candidate function template not viable: requires 3 arguments, but 2 were provided
max(const _Tp& __a, const _Tp& __b, _Compare __comp)
^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:2735:1: note: candidate function template not viable: requires single argument '__t', but 2 arguments were provided
max(initializer_list<_Tp> __t)
^
1 error generated.
make: *** [tools/db_bench_tool.o] Error 1
```

My compiler version:
Mac OS X Mojave
```
$ clang++ --version
Apple LLVM version 10.0.0 (clang-1000.11.45.5)
Target: x86_64-apple-darwin18.2.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4722

Differential Revision: D13220196

Pulled By: sagar0

fbshipit-source-id: 01e5e928288a5613027c83a26ad8aedf04438b14

Summary:
A user friendly sst file reader is useful when we want to access sst
files outside of RocksDB. For example, we can generate an sst file
with SstFileWriter and send it to other places, then use SstFileReader
to read the file and process the entries in other ways.

Also rename the original SstFileReader to SstFileDumper because of
name conflict, and seems SstFileDumper is more appropriate for tools.

TODO: there is only a very simple test now, because I want to get some feedback first.
If the changes look good, I will add more tests soon.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4717

Differential Revision: D13212686

Pulled By: ajkr

fbshipit-source-id: 737593383264c954b79e63edaf44aaae0d947e56

Summary:
Simple patch to address comments in [statistics.h#L65](https://github.com/facebook/rocksdb/blob/master/monitoring/statistics.h#L65|statistics.h#L65)  `TODO(ajkr): clean this up since there are no internal stats anymore`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4714

Differential Revision: D13208093

Pulled By: ajkr

fbshipit-source-id: 4468badb850592411147539f859082644f5296f6

Summary:
DeleteRange is now ready for production use. Change the header comment to reflect this, and update HISTORY.md with the feature's status.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4709

Differential Revision: D13209055

Pulled By: abhimadan

fbshipit-source-id: 65423eb1a4927cf593c38254cd87c322f73ae137

Summary:
Adding sanity check test for mapping of `Histograms` and `HistogramsNameMap`

```
[==========] Running 2 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 2 tests from StatisticsTest
[ RUN      ] StatisticsTest.SanityTickers
[       OK ] StatisticsTest.SanityTickers (0 ms)
[ RUN      ] StatisticsTest.SanityHistograms
[       OK ] StatisticsTest.SanityHistograms (0 ms)
[----------] 2 tests from StatisticsTest (0 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 1 test case ran. (0 ms total)
[  PASSED  ] 2 tests.
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4720

Differential Revision: D13217061

Pulled By: ajkr

fbshipit-source-id: 6427f4e684c36b2f3c3440808b74fee86a364683

Summary:
Added back `NO_ITERATORS` and moved `NO_ITERATOR_CREATED` to the end of `toCppTickers`.

This is a leftover fix which is needed in addition to a138e351 to correctly convert java tickers to c++ tickers. a138e351 only updated `toJavaTickerType` but both `toJavaTickerType` and `toCppTickers` need to be changed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4719

Differential Revision: D13208847

Pulled By: sagar0

fbshipit-source-id: 53a42f3d6ffe04034acfde972d73040b92b4c1af

Summary:
The error message of databases/rocksdb-lite (FreeBSD port) is as follows:
```
  tools/db_bench_tool.cc:1976:16: error: private field 'trace_options_' is not used [-Werror,-Wunused-private-field]
    TraceOptions trace_options_;
                 ^
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4715

Differential Revision: D13207902

Pulled By: ajkr

fbshipit-source-id: be3c612eba656aeddb77e35e2f201dd25dc92f7e

Summary:
Summary

We should declare constants in headers and define them in source files.
But this commit is only aimed at compound types.

I don't know if it is necessary to do the same thing to fundamental types.

I used this command to find all of the constant definitions in header files.

`find . -name "*.h" | xargs grep -e "^const .*=.*"`

And here is what I found:

```
./db/version_edit.h:const uint64_t kFileNumberMask = 0x3FFFFFFFFFFFFFFF;
./include/rocksdb/env.h:const size_t kDefaultPageSize = 4 * 1024;
./include/rocksdb/statistics.h:const std::vector<std::pair<Tickers, std::string>> TickersNameMap = {
./include/rocksdb/statistics.h:const std::vector<std::pair<Histograms, std::string>> HistogramsNameMap = {
./include/rocksdb/table.h:const uint32_t kPlainTableVariableLength = 0;
./include/rocksdb/utilities/transaction_db.h:const uint32_t kInitialMaxDeadlocks = 5;
./port/port_posix.h:const uint32_t kMaxUint32 = std::numeric_limits<uint32_t>::max();
./port/port_posix.h:const int kMaxInt32 = std::numeric_limits<int32_t>::max();
./port/port_posix.h:const uint64_t kMaxUint64 = std::numeric_limits<uint64_t>::max();
./port/port_posix.h:const int64_t kMaxInt64 = std::numeric_limits<int64_t>::max();
./port/port_posix.h:const size_t kMaxSizet = std::numeric_limits<size_t>::max();
./port/win/port_win.h:const uint32_t kMaxUint32 = UINT32_MAX;
./port/win/port_win.h:const int kMaxInt32 = INT32_MAX;
./port/win/port_win.h:const int64_t kMaxInt64 = INT64_MAX;
./port/win/port_win.h:const uint64_t kMaxUint64 = UINT64_MAX;
./port/win/port_win.h:const size_t kMaxSizet = UINT64_MAX;
./port/win/port_win.h:const size_t kMaxSizet = UINT_MAX;
./port/win/port_win.h:const uint32_t kMaxUint32 = std::numeric_limits<uint32_t>::max();
./port/win/port_win.h:const int kMaxInt32 = std::numeric_limits<int>::max();
./port/win/port_win.h:const uint64_t kMaxUint64 = std::numeric_limits<uint64_t>::max();
./port/win/port_win.h:const int64_t kMaxInt64 = std::numeric_limits<int64_t>::max();
./port/win/port_win.h:const size_t kMaxSizet = std::numeric_limits<size_t>::max();
./port/win/port_win.h:const bool kLittleEndian = true;
./table/cuckoo_table_factory.h:const uint32_t kCuckooMurmurSeedMultiplier = 816922183;
./table/data_block_hash_index.h:const uint8_t kNoEntry = 255;
./table/data_block_hash_index.h:const uint8_t kCollision = 254;
./table/data_block_hash_index.h:const uint8_t kMaxRestartSupportedByHashIndex = 253;
./table/data_block_hash_index.h:const size_t kMaxBlockSizeSupportedByHashIndex = 1u << 16;
./table/data_block_hash_index.h:const double kDefaultUtilRatio = 0.75;
./table/filter_block.h:const uint64_t kNotValid = ULLONG_MAX;
./table/format.h:const int kMagicNumberLengthByte = 8;
./third-party/fbson/FbsonJsonParser.h:const char* const kJsonDelim = " ,]}\t\r\n";
./third-party/fbson/FbsonJsonParser.h:const char* const kWhiteSpace = " \t\n\r";
./third-party/gtest-1.7.0/fused-src/gtest/gtest.h:const BiggestInt kMaxBiggestInt =
./third-party/gtest-1.7.0/fused-src/gtest/gtest.h:const char kDeathTestStyleFlag[] = "death_test_style";
./third-party/gtest-1.7.0/fused-src/gtest/gtest.h:const char kDeathTestUseFork[] = "death_test_use_fork";
./third-party/gtest-1.7.0/fused-src/gtest/gtest.h:const char kInternalRunDeathTestFlag[] = "internal_run_death_test";
./third-party/gtest-1.7.0/fused-src/gtest/gtest.h:const char* pets[] = {"cat", "dog"};
./third-party/gtest-1.7.0/fused-src/gtest/gtest.h:const size_t kProtobufOneLinerMaxLength = 50;
./third-party/gtest-1.7.0/fused-src/gtest/gtest.h:const int kMaxStackTraceDepth = 100;
./third-party/gtest-1.7.0/fused-src/gtest/gtest.h:const T* WithParamInterface<T>::parameter_ = NULL;
./util/coding.h:const unsigned int kMaxVarint64Length = 10;
./util/filename.h:const size_t kFormatFileNumberBufSize = 38;
./util/testutil.h:const SliceTransform* RandomSliceTransform(Random* rnd, int pre_defined = -1);
./util/trace_replay.h:const std::string kTraceMagic = "feedcafedeadbeef";
./util/trace_replay.h:const unsigned int kTraceTimestampSize = 8;
./util/trace_replay.h:const unsigned int kTraceTypeSize = 1;
./util/trace_replay.h:const unsigned int kTracePayloadLengthSize = 4;
./util/trace_replay.h:const unsigned int kTraceMetadataSize =
./utilities/cassandra/serialize.h:const int64_t kCharMask = 0xFFLL;
./utilities/cassandra/serialize.h:const int32_t kBitsPerByte = 8;
```

And these 3 lines are related to this commit:

```
./include/rocksdb/statistics.h:const std::vector<std::pair<Tickers, std::string>> TickersNameMap = {
./include/rocksdb/statistics.h:const std::vector<std::pair<Histograms, std::string>> HistogramsNameMap = {
./util/trace_replay.h:const std::string kTraceMagic = "feedcafedeadbeef";
```

Any comments would be appreciated.
Thanks.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4691

Differential Revision: D13208049

Pulled By: ajkr

fbshipit-source-id: e5ee55fdaec5447fc5798c6721e2821e7cdc0d5b

Summary:
Make CompactionOptionsFIFO's ttl and allow_compaction options to be available in RocksJava.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4609

Differential Revision: D12849503

Pulled By: sagar0

fbshipit-source-id: 47baa97918d252370f234c36c1af15ff2dad7658

Summary:
Previously, every range tombstone iterator was seeked on every
ShouldDelete call, which quickly degraded performance for long range
scans. This PR improves performance by tracking iterator positions and
only advancing iterators when necessary.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4677

Differential Revision: D13205373

Pulled By: abhimadan

fbshipit-source-id: 80c199dace1e19362a4c61c686bf01913eae87cb

Summary:
… (#4656)"

This reverts commit b76398a8.

Will add test coverage for iterate_upper_bound before re-commit b76398
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4705

Differential Revision: D13148592

Pulled By: miasantreble

fbshipit-source-id: 4d1ce0bfd9f7a5359a7688bd780eb06a66f45b1f

Summary:
as titled
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4711

Differential Revision: D13166391

Pulled By: ajkr

fbshipit-source-id: 3a3e537cebe2ba97a7ae6fcc3282db2ea755158e

Summary:
We haven't been populating `NO_FILE_CLOSES` since v1.5.8 even though it was never marked as deprecated. Start populating it again. Conveniently `DeleteTableReader` has an unused `void*` argument that we can use...

Blame: 63f216ee

Closes #4700.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4703

Differential Revision: D13146769

Pulled By: ajkr

fbshipit-source-id: ad8d6fb0493e701f60a165a3bca1787d255be008

Summary:
…ons (#4676)"

This reverts commit b32d087d.

`MemoryAllocator` needs to be with `Cache`, since cache entry can
outlive DB and block based table. The cache needs to hold reference to
memory allocator when deleting cache entry.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4697

Differential Revision: D13133490

Pulled By: yiwu-arbug

fbshipit-source-id: 8ef7e8a51263bfd929f892fd062665ff4ce9ce5a

Summary:
The old RangeDelAggregator did expensive pre-processing work
to create a collapsed, binary-searchable representation of range
tombstones. With FragmentedRangeTombstoneIterator, much of this work is
now unnecessary. RangeDelAggregatorV2 takes advantage of this by seeking
in each iterator to find a covering tombstone in ShouldDelete, while
doing minimal work in AddTombstones. The old RangeDelAggregator is still
used during flush/compaction for now, though RangeDelAggregatorV2 will
support those uses in a future PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4649

Differential Revision: D13146964

Pulled By: abhimadan

fbshipit-source-id: be29a4c020fc440500c137216fcc1cf529571eb3

Summary:
Since a range tombstone seen at one level will cover all keys
in the range at lower levels, there was a short-circuiting check in Get
that reported a key was not found at most one file after the range
tombstone was discovered. However, this was incorrect for merge
operands, since a deletion might only cover some merge operands,
which implies that the key should be found. This PR fixes this logic in
the Version portion of Get, and removes the logic from the MemTable
portion of Get, since the perforamnce benefit provided there is minimal.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4698

Differential Revision: D13142484

Pulled By: abhimadan

fbshipit-source-id: cbd74537c806032f2bfa564724d01a80df7c8f10

Summary:
- Added back the `NO_ITERATORS` that was removed in 5945e16d.
- Marked it as deprecated since it is no longer populated, but kept for API compatibility.
- Made sure the new tickers, `NO_ITERATOR_CREATED` and `NO_ITERATOR_DELETED`, are appended at the end of the enum, in case people are relying on the int values.

The change where `NO_ITERATOR_CREATED` and `NO_ITERATOR_DELETED` were introduced is unreleased so I believe it is ok to change their ordering.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4701

Differential Revision: D13142887

Pulled By: ajkr

fbshipit-source-id: 29a336ce5b46632ce50ad42ccc4a29013f71d6d6

Summary:
Add option to support  thread-local tcache to reduce mutex contention inside Jemalloc arena.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4603

Differential Revision: D12830738

Pulled By: yiwu-arbug

fbshipit-source-id: 59bd25b165b903f23a6a8531b18d72e140d69f65

Summary:
Found a callsite for `moo_translate` in the Scuba warnings and realized we have a few calls to `define()` left in fbcode.

- I ran the `DefineCodemod` script against fbcode
- Fixed broken tests, and ensured that tests that are explicitly testing the behaviour of `define()` were not changed.

bypass-lint

Reviewed By: kmeht

Differential Revision: D12968447

fbshipit-source-id: d8fd3649a2ce9868b8938d293e1bebf1a6d2fad8

Summary:
WriteBufferManger is not invoked when allocating memory for memtable if the limit is not set even if a cache is passed. It is inconsistent from the comment syas. Fix it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4695

Differential Revision: D13112722

Pulled By: siying

fbshipit-source-id: 0b27eef63867f679cd06033ea56907c0569597f4

Summary:
This is a quick fix for the uninitialized bugs in `LiveFileMetaData` and `SstFileMetaData` that were uncovered in #4686.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4693

Differential Revision: D13113189

Pulled By: ajkr

fbshipit-source-id: 18e798d031d2a59d0b55fc010c135e0126f4042d

Summary:
This fixes an assertion.

An atomic flush can have multiple flush jobs. Some of them may fail. If any of
them fails, we need to rollback all of them.
For the flush jobs that do fail, we already call `RollbackMemTableFlush` in
`FlushJob::Run`. The tricky part is for flush jobs that have completed
successfully. We need to call `RollbackMemTableFlush` for them as well.

The newly added DBAtomicFlushTest.AtomicFlushRollbackSomeJobs will SigAbort
without the corresponding change in AtomicFlushMemTablesToOutputFiles.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4641

Differential Revision: D12943649

Pulled By: riversand963

fbshipit-source-id: c66a4a664a1e0938e938fd41edc5a70c34cdd868

Summary:
Rather than storing a `vector<RangeTombstone>`, we now store a
`vector<RangeTombstoneStack>` and a `vector<SequenceNumber>`. A
`RangeTombstoneStack` contains the start and end keys of a range tombstone
fragment, and indices into the seqnum vector to indicate which sequence
numbers the fragment is located at. The diagram below illustrates an
example:

```
tombstones_:     [a, b) [c, e) [h, k)
                   | \   /  \   /  |
                   |  \ /    \ /   |
                   v   v      v    v
tombstone_seqs_: [ 5 3 10 7 2 8 6  ]
```

This format allows binary searching the tombstone list to use less key
comparisons, which helps in cases where there are many overlapping
tombstones. Also, this format makes it easier to add DBIter-like
semantics to `FragmentedRangeTombstoneIterator` in the future.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4632

Differential Revision: D13053103

Pulled By: abhimadan

fbshipit-source-id: e8220cc712fcf5be4d602913bb23ace8ea5f8ef0

Summary:
DBTest.SanitizeNumThreads Sometimes fails. The test waited for 10ms timeout and expect all threads scheduled to be executed. This can be a source of flakiness. Make a check every 1ms and up to 10s.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4659

Differential Revision: D13074174

Pulled By: siying

fbshipit-source-id: b1d5ff87a326a4fc9eab8d1cc307bbb940dfe70c

Summary:
The default implementation of GetForUpdate that receives PinnableSlice was mistakenly dropping column_family and exclusive parameters.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4679

Differential Revision: D13062531

Pulled By: maysamyabandeh

fbshipit-source-id: 7625d0c1ba872a5d894b58ced42147d6c8556a6f

Summary:
The new flag makes it possible to constrain iterator traversal
by the upper/lower bound the iterator is expected to pass. This allows
seekrandom results to be more easily comparable between DBs with and
without deletions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4660

Differential Revision: D13053111

Pulled By: abhimadan

fbshipit-source-id: 33e250f2e2d210b54c7726399da30a33f723c33c

Summary:
When iterator becomes invalid, there are two possibilities.
First, all data in the column family have been scanned and there is nothing
more to scan.
Second, an underlying error has occurred, causing `status()` to be !ok.
Therefore, we need to check for both cases when `!iter->Valid()`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4648

Differential Revision: D12959601

Pulled By: riversand963

fbshipit-source-id: 49c9382c9ea9e78f2e2b6f3708f0670b822ca8dd

Summary:
adamretter

As you already mentioned at #1247 .
Pull Request resolved: https://github.com/facebook/rocksdb/pull/2303

Differential Revision: D10209001

Pulled By: sagar0

fbshipit-source-id: bcbce004112c2edeaff116968d79c6f90aab4b6c

Summary:
`GenSubcompactionBoundaries` calls `VersionSet::ApproximateSize` which gets BlockBasedTableReader for every file and seeks in its index block to find `key`'s offset. If the table or index block aren't in memory already, this involves I/O. This can be improved by releasing DB mutex when calling ApproximateSize.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4630

Differential Revision: D13052653

Pulled By: miasantreble

fbshipit-source-id: cae31d46d10d0860fa8a26b8d5154b2d17d1685f

Remove two variables from BlockContents class and don't use class Block for compressed block (#4650)

Summary:
We carry compression type and "cachable" variables for every block in the block cache, while they take well-known values. 8-byte is wasted for each block (2-byte for useful information but it takes 8 bytes because of padding). With this change, these two variables are removed.

The cachable information is only useful in the process of reading the block. We use other information to infer from it. For compressed blocks, the compression type is a part of the block content itself so we can get it from there.

Some code is slightly refactored so that the cachable information can flow better.

Another change is to only use class BlockContents for compressed block, and narrow the class Block to only be used for uncompressed blocks, including blocks in compressed block cache. This can make the Block class less confusing. It also saves tens of bytes for each block in compressed block cache.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4650

Differential Revision: D12969070

Pulled By: siying

fbshipit-source-id: 548b62724e9eb66993026429fd9c7c3acd1f95ed

Summary:
Currently transaction iterator does not apply `ReadOptions.iterate_upper_bound` when iterating. This PR attempts to fix the problem by having `BaseDeltaIterator` enforcing the upper bound check when iterator state is changed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4656

Differential Revision: D13039257

Pulled By: miasantreble

fbshipit-source-id: 909eb9f6b4597a4d80418fb139f32ec82c6ec1d1

Summary:
It called the autovector::push_back simply in autovector::emplace_back.
This was not efficient, and then optimazed this function through the
perfect forwarding.

This was the src and result of the benchmark(using the google'benchmark library, the type of elem in
autovector was std::string, and call emplace_back with the "char *" type):

https://gist.github.com/monadbobo/93448b89a42737b08cbada81de75c5cd

PS: The benchmark's result of  previous PR was not accurate, and so I update the test case and result.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4606

Differential Revision: D13046813

Pulled By: sagar0

fbshipit-source-id: 19cde1bcadafe899aa454b703acb35737a1cc02d